com.mawujun.utils.string.StringUtils.java Source code

Java tutorial

Introduction

Here is the source code for com.mawujun.utils.string.StringUtils.java

Source

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.mawujun.utils.string;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Properties;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.lang3.ArrayUtils;

import com.mawujun.utils.CollectionUtils;
import com.mawujun.utils.ObjectUtils;

public class StringUtils extends org.apache.commons.lang3.StringUtils {
    private static final String FOLDER_SEPARATOR = "/";

    private static final String WINDOWS_FOLDER_SEPARATOR = "\\";

    private static final String TOP_PATH = "..";

    private static final String CURRENT_PATH = ".";

    private static final char EXTENSION_SEPARATOR = '.';

    public static final char UNDERLINE = '_';

    /**
     * ?
     * @author mawujun email:160649888@163.com qq:16064988
     * @param param
     * @return
     */
    public static String camelToUnderline(String param) {
        if (param == null || "".equals(param.trim())) {
            return "";
        }
        int len = param.length();
        StringBuilder sb = new StringBuilder(len);
        for (int i = 0; i < len; i++) {
            char c = param.charAt(i);
            if (Character.isUpperCase(c)) {
                sb.append(UNDERLINE);
                sb.append(Character.toLowerCase(c));
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }

    /**
     *  ?
     * @author mawujun email:160649888@163.com qq:16064988
     * @param param
     * @return
     */
    public static String underlineToCamel(String param) {
        if (param == null || "".equals(param.trim())) {
            return "";
        }
        int len = param.length();
        StringBuilder sb = new StringBuilder(len);
        for (int i = 0; i < len; i++) {
            char c = param.charAt(i);
            if (c == UNDERLINE) {
                if (++i < len) {
                    sb.append(Character.toUpperCase(param.charAt(i)));
                }
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }

    /**
     *  ?
     * @author mawujun email:160649888@163.com qq:16064988
     * @param param
     * @return
     */
    public static String underlineToCamel2(String param) {
        if (param == null || "".equals(param.trim())) {
            return "";
        }
        StringBuilder sb = new StringBuilder(param);
        Matcher mc = Pattern.compile("_").matcher(param);
        int i = 0;
        while (mc.find()) {
            int position = mc.end() - (i++);
            // String.valueOf(Character.toUpperCase(sb.charAt(position)));
            sb.replace(position - 1, position + 1, sb.substring(position, position + 1).toUpperCase());
        }
        return sb.toString();
    }

    // ---------------------------------------------------------------------
    // General convenience methods for working with Strings
    // ---------------------------------------------------------------------

    /**
     * Check that the given CharSequence is neither <code>null</code> nor of
     * length 0. Note: Will return <code>true</code> for a CharSequence that
     * purely consists of whitespace.
     * <p>
     * 
     * <pre>
     * StringUtils.hasLength(null) = false
     * StringUtils.hasLength("") = false
     * StringUtils.hasLength(" ") = true
     * StringUtils.hasLength("Hello") = true
     * </pre>
     * 
     * @param str
     *            the CharSequence to check (may be <code>null</code>)
     * @return <code>true</code> if the CharSequence is not null and has length
     * @see #hasText(String)
     */
    public static boolean hasLength(CharSequence str) {
        return (str != null && str.length() > 0);
    }

    /**
     * Check that the given String is neither <code>null</code> nor of length 0.
     * Note: Will return <code>true</code> for a String that purely consists of
     * whitespace.
     * 
     * @param str
     *            the String to check (may be <code>null</code>)
     * @return <code>true</code> if the String is not null and has length
     * @see #hasLength(CharSequence)
     */
    public static boolean hasLength(String str) {
        return hasLength((CharSequence) str);
    }

    /**
     * Check whether the given CharSequence has actual text. More specifically,
     * returns <code>true</code> if the string not <code>null</code>, its length
     * is greater than 0, and it contains at least one non-whitespace character.
     * <p>
     * 
     * <pre>
     * StringUtils.hasText(null) = false
     * StringUtils.hasText("") = false
     * StringUtils.hasText(" ") = false
     * StringUtils.hasText("12345") = true
     * StringUtils.hasText(" 12345 ") = true
     * </pre>
     * 
     * @param str
     *            the CharSequence to check (may be <code>null</code>)
     * @return <code>true</code> if the CharSequence is not <code>null</code>,
     *         its length is greater than 0, and it does not contain whitespace
     *         only
     * @see java.lang.Character#isWhitespace
     */
    public static boolean hasText(CharSequence str) {
        if (!hasLength(str)) {
            return false;
        }
        int strLen = str.length();
        for (int i = 0; i < strLen; i++) {
            if (!Character.isWhitespace(str.charAt(i))) {
                return true;
            }
        }
        return false;
    }

    /**
     * Check whether the given String has actual text. More specifically,
     * returns <code>true</code> if the string not <code>null</code>, its length
     * is greater than 0, and it contains at least one non-whitespace character.
     * 
     * @param str
     *            the String to check (may be <code>null</code>)
     * @return <code>true</code> if the String is not <code>null</code>, its
     *         length is greater than 0, and it does not contain whitespace only
     * @see #hasText(CharSequence)
     */
    public static boolean hasText(String str) {
        return hasText((CharSequence) str);
    }

    /**
     * Check whether the given CharSequence contains any whitespace characters.
     * 
     * @param str
     *            the CharSequence to check (may be <code>null</code>)
     * @return <code>true</code> if the CharSequence is not empty and contains
     *         at least 1 whitespace character
     * @see java.lang.Character#isWhitespace
     */
    public static boolean containsWhitespace(CharSequence str) {
        if (!hasLength(str)) {
            return false;
        }
        int strLen = str.length();
        for (int i = 0; i < strLen; i++) {
            if (Character.isWhitespace(str.charAt(i))) {
                return true;
            }
        }
        return false;
    }

    /**
     * Check whether the given String contains any whitespace characters.
     * 
     * @param str
     *            the String to check (may be <code>null</code>)
     * @return <code>true</code> if the String is not empty and contains at
     *         least 1 whitespace character
     * @see #containsWhitespace(CharSequence)
     */
    public static boolean containsWhitespace(String str) {
        return containsWhitespace((CharSequence) str);
    }

    /**
     * Trim leading and trailing whitespace from the given String.
     * 
     * @param str
     *            the String to check
     * @return the trimmed String
     * @see java.lang.Character#isWhitespace
     */
    public static String trimWhitespace(String str) {
        if (!hasLength(str)) {
            return str;
        }
        StringBuilder sb = new StringBuilder(str);
        while (sb.length() > 0 && Character.isWhitespace(sb.charAt(0))) {
            sb.deleteCharAt(0);
        }
        while (sb.length() > 0 && Character.isWhitespace(sb.charAt(sb.length() - 1))) {
            sb.deleteCharAt(sb.length() - 1);
        }
        return sb.toString();
    }

    /**
     * Trim <i>all</i> whitespace from the given String: leading, trailing, and
     * inbetween characters.
     * 
     * @param str
     *            the String to check
     * @return the trimmed String
     * @see java.lang.Character#isWhitespace
     */
    public static String trimAllWhitespace(String str) {
        if (!hasLength(str)) {
            return str;
        }
        StringBuilder sb = new StringBuilder(str);
        int index = 0;
        while (sb.length() > index) {
            if (Character.isWhitespace(sb.charAt(index))) {
                sb.deleteCharAt(index);
            } else {
                index++;
            }
        }
        return sb.toString();
    }

    /**
     * Trim leading whitespace from the given String.
     * 
     * @param str
     *            the String to check
     * @return the trimmed String
     * @see java.lang.Character#isWhitespace
     */
    public static String trimLeadingWhitespace(String str) {
        if (!hasLength(str)) {
            return str;
        }
        StringBuilder sb = new StringBuilder(str);
        while (sb.length() > 0 && Character.isWhitespace(sb.charAt(0))) {
            sb.deleteCharAt(0);
        }
        return sb.toString();
    }

    /**
     * Trim trailing whitespace from the given String.
     * 
     * @param str
     *            the String to check
     * @return the trimmed String
     * @see java.lang.Character#isWhitespace
     */
    public static String trimTrailingWhitespace(String str) {
        if (!hasLength(str)) {
            return str;
        }
        StringBuilder sb = new StringBuilder(str);
        while (sb.length() > 0 && Character.isWhitespace(sb.charAt(sb.length() - 1))) {
            sb.deleteCharAt(sb.length() - 1);
        }
        return sb.toString();
    }

    /**
     * Trim all occurences of the supplied leading character from the given
     * String.
     * 
     * @param str
     *            the String to check
     * @param leadingCharacter
     *            the leading character to be trimmed
     * @return the trimmed String
     */
    public static String trimLeadingCharacter(String str, char leadingCharacter) {
        if (!hasLength(str)) {
            return str;
        }
        StringBuilder sb = new StringBuilder(str);
        while (sb.length() > 0 && sb.charAt(0) == leadingCharacter) {
            sb.deleteCharAt(0);
        }
        return sb.toString();
    }

    /**
     * Trim all occurences of the supplied trailing character from the given
     * String.
     * 
     * @param str
     *            the String to check
     * @param trailingCharacter
     *            the trailing character to be trimmed
     * @return the trimmed String
     */
    public static String trimTrailingCharacter(String str, char trailingCharacter) {
        if (!hasLength(str)) {
            return str;
        }
        StringBuilder sb = new StringBuilder(str);
        while (sb.length() > 0 && sb.charAt(sb.length() - 1) == trailingCharacter) {
            sb.deleteCharAt(sb.length() - 1);
        }
        return sb.toString();
    }

    /**
     * Test if the given String starts with the specified prefix, ignoring
     * upper/lower case.
     * 
     * @param str
     *            the String to check
     * @param prefix
     *            the prefix to look for
     * @see java.lang.String#startsWith
     */
    public static boolean startsWithIgnoreCase(String str, String prefix) {
        if (str == null || prefix == null) {
            return false;
        }
        if (str.startsWith(prefix)) {
            return true;
        }
        if (str.length() < prefix.length()) {
            return false;
        }
        String lcStr = str.substring(0, prefix.length()).toLowerCase();
        String lcPrefix = prefix.toLowerCase();
        return lcStr.equals(lcPrefix);
    }

    /**
     * Test if the given String ends with the specified suffix, ignoring
     * upper/lower case.
     * 
     * @param str
     *            the String to check
     * @param suffix
     *            the suffix to look for
     * @see java.lang.String#endsWith
     */
    public static boolean endsWithIgnoreCase(String str, String suffix) {
        if (str == null || suffix == null) {
            return false;
        }
        if (str.endsWith(suffix)) {
            return true;
        }
        if (str.length() < suffix.length()) {
            return false;
        }

        String lcStr = str.substring(str.length() - suffix.length()).toLowerCase();
        String lcSuffix = suffix.toLowerCase();
        return lcStr.equals(lcSuffix);
    }

    /**
     * Test whether the given string matches the given substring at the given
     * index.
     * 
     * @param str
     *            the original string (or StringBuilder)
     * @param index
     *            the index in the original string to start matching against
     * @param substring
     *            the substring to match at the given index
     */
    public static boolean substringMatch(CharSequence str, int index, CharSequence substring) {
        for (int j = 0; j < substring.length(); j++) {
            int i = index + j;
            if (i >= str.length() || str.charAt(i) != substring.charAt(j)) {
                return false;
            }
        }
        return true;
    }

    /**
     * Count the occurrences of the substring in string s.
     * 
     * @param str
     *            string to search in. Return 0 if this is null.
     * @param sub
     *            string to search for. Return 0 if this is null.
     */
    public static int countOccurrencesOf(String str, String sub) {
        if (str == null || sub == null || str.length() == 0 || sub.length() == 0) {
            return 0;
        }
        int count = 0;
        int pos = 0;
        int idx;
        while ((idx = str.indexOf(sub, pos)) != -1) {
            ++count;
            pos = idx + sub.length();
        }
        return count;
    }

    /**
     * Replace all occurences of a substring within a string with another
     * string.
     * 
     * @param inString
     *            String to examine
     * @param oldPattern
     *            String to replace
     * @param newPattern
     *            String to insert
     * @return a String with the replacements
     */
    public static String replace(String inString, String oldPattern, String newPattern) {
        if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null) {
            return inString;
        }
        StringBuilder sb = new StringBuilder();
        int pos = 0; // our position in the old string
        int index = inString.indexOf(oldPattern);
        // the index of an occurrence we've found, or -1
        int patLen = oldPattern.length();
        while (index >= 0) {
            sb.append(inString.substring(pos, index));
            sb.append(newPattern);
            pos = index + patLen;
            index = inString.indexOf(oldPattern, pos);
        }
        sb.append(inString.substring(pos));
        // remember to append any characters to the right of a match
        return sb.toString();
    }

    /**
     * Delete all occurrences of the given substring.
     * 
     * @param inString
     *            the original String
     * @param pattern
     *            the pattern to delete all occurrences of
     * @return the resulting String
     */
    public static String delete(String inString, String pattern) {
        return replace(inString, pattern, "");
    }

    /**
     * Delete any character in a given String.
     * 
     * @param inString
     *            the original String
     * @param charsToDelete
     *            a set of characters to delete. E.g. "az\n" will delete 'a's,
     *            'z's and new lines.
     * @return the resulting String
     */
    public static String deleteAny(String inString, String charsToDelete) {
        if (!hasLength(inString) || !hasLength(charsToDelete)) {
            return inString;
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < inString.length(); i++) {
            char c = inString.charAt(i);
            if (charsToDelete.indexOf(c) == -1) {
                sb.append(c);
            }
        }
        return sb.toString();
    }

    // ---------------------------------------------------------------------
    // Convenience methods for working with formatted Strings
    // ---------------------------------------------------------------------

    /**
     * Quote the given String with single quotes.
     * 
     * @param str
     *            the input String (e.g. "myString")
     * @return the quoted String (e.g. "'myString'"), or
     *         <code>null<code> if the input was <code>null</code>
     */
    public static String quote(String str) {
        return (str != null ? "'" + str + "'" : null);
    }

    /**
     * Turn the given Object into a String with single quotes if it is a String;
     * keeping the Object as-is else.
     * 
     * @param obj
     *            the input Object (e.g. "myString")
     * @return the quoted String (e.g. "'myString'"), or the input object as-is
     *         if not a String
     */
    public static Object quoteIfString(Object obj) {
        return (obj instanceof String ? quote((String) obj) : obj);
    }

    /**
     * Unqualify a string qualified by a '.' dot character. For example,
     * "this.name.is.qualified", returns "qualified".
     * 
     * @param qualifiedName
     *            the qualified name
     */
    public static String unqualify(String qualifiedName) {
        return unqualify(qualifiedName, '.');
    }

    /**
     * Unqualify a string qualified by a separator character. For example,
     * "this:name:is:qualified" returns "qualified" if using a ':' separator.
     * 
     * @param qualifiedName
     *            the qualified name
     * @param separator
     *            the separator
     */
    public static String unqualify(String qualifiedName, char separator) {
        return qualifiedName.substring(qualifiedName.lastIndexOf(separator) + 1);
    }

    /**
     * Capitalize a <code>String</code>, changing the first letter to upper case
     * as per {@link Character#toUpperCase(char)}. No other letters are changed.
     * 
     * @param str
     *            the String to capitalize, may be <code>null</code>
     * @return the capitalized String, <code>null</code> if null
     */
    public static String capitalize(String str) {
        return changeFirstCharacterCase(str, true);
    }

    /**
     * Uncapitalize a <code>String</code>, changing the first letter to lower
     * case as per {@link Character#toLowerCase(char)}. No other letters are
     * changed.
     * 
     * @param str
     *            the String to uncapitalize, may be <code>null</code>
     * @return the uncapitalized String, <code>null</code> if null
     */
    public static String uncapitalize(String str) {
        return changeFirstCharacterCase(str, false);
    }

    private static String changeFirstCharacterCase(String str, boolean capitalize) {
        if (str == null || str.length() == 0) {
            return str;
        }
        StringBuilder sb = new StringBuilder(str.length());
        if (capitalize) {
            sb.append(Character.toUpperCase(str.charAt(0)));
        } else {
            sb.append(Character.toLowerCase(str.charAt(0)));
        }
        sb.append(str.substring(1));
        return sb.toString();
    }

    /**
     * Extract the filename from the given path, e.g. "mypath/myfile.txt" ->
     * "myfile.txt".
     * 
     * @param path
     *            the file path (may be <code>null</code>)
     * @return the extracted filename, or <code>null</code> if none
     */
    public static String getFilename(String path) {
        if (path == null) {
            return null;
        }
        int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
        return (separatorIndex != -1 ? path.substring(separatorIndex + 1) : path);
    }

    /**
     * Extract the filename extension from the given path, e.g.
     * "mypath/myfile.txt" -> "txt".
     * 
     * @param path
     *            the file path (may be <code>null</code>)
     * @return the extracted filename extension, or <code>null</code> if none
     */
    public static String getFilenameExtension(String path) {
        if (path == null) {
            return null;
        }
        int extIndex = path.lastIndexOf(EXTENSION_SEPARATOR);
        if (extIndex == -1) {
            return null;
        }
        int folderIndex = path.lastIndexOf(FOLDER_SEPARATOR);
        if (folderIndex > extIndex) {
            return null;
        }
        return path.substring(extIndex + 1);
    }

    /**
     * Strip the filename extension from the given path, e.g.
     * "mypath/myfile.txt" -> "mypath/myfile".
     * 
     * @param path
     *            the file path (may be <code>null</code>)
     * @return the path with stripped filename extension, or <code>null</code>
     *         if none
     */
    public static String stripFilenameExtension(String path) {
        if (path == null) {
            return null;
        }
        int extIndex = path.lastIndexOf(EXTENSION_SEPARATOR);
        if (extIndex == -1) {
            return path;
        }
        int folderIndex = path.lastIndexOf(FOLDER_SEPARATOR);
        if (folderIndex > extIndex) {
            return path;
        }
        return path.substring(0, extIndex);
    }

    /**
     * Apply the given relative path to the given path, assuming standard Java
     * folder separation (i.e. "/" separators).
     * 
     * @param path
     *            the path to start from (usually a full file path)
     * @param relativePath
     *            the relative path to apply (relative to the full file path
     *            above)
     * @return the full file path that results from applying the relative path
     */
    public static String applyRelativePath(String path, String relativePath) {
        int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
        if (separatorIndex != -1) {
            String newPath = path.substring(0, separatorIndex);
            if (!relativePath.startsWith(FOLDER_SEPARATOR)) {
                newPath += FOLDER_SEPARATOR;
            }
            return newPath + relativePath;
        } else {
            return relativePath;
        }
    }

    /**
     * Normalize the path by suppressing sequences like "path/.." and inner
     * simple dots.
     * <p>
     * The result is convenient for path comparison. For other uses, notice that
     * Windows separators ("\") are replaced by simple slashes.
     * 
     * @param path
     *            the original path
     * @return the normalized path
     */
    public static String cleanPath(String path) {
        if (path == null) {
            return null;
        }
        String pathToUse = replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);

        // Strip prefix from path to analyze, to not treat it as part of the
        // first path element. This is necessary to correctly parse paths like
        // "file:core/../core/io/Resource.class", where the ".." should just
        // strip the first "core" directory while keeping the "file:" prefix.
        int prefixIndex = pathToUse.indexOf(":");
        String prefix = "";
        if (prefixIndex != -1) {
            prefix = pathToUse.substring(0, prefixIndex + 1);
            pathToUse = pathToUse.substring(prefixIndex + 1);
        }
        if (pathToUse.startsWith(FOLDER_SEPARATOR)) {
            prefix = prefix + FOLDER_SEPARATOR;
            pathToUse = pathToUse.substring(1);
        }

        String[] pathArray = delimitedListToStringArray(pathToUse, FOLDER_SEPARATOR);
        List<String> pathElements = new LinkedList<String>();
        int tops = 0;

        for (int i = pathArray.length - 1; i >= 0; i--) {
            String element = pathArray[i];
            if (CURRENT_PATH.equals(element)) {
                // Points to current directory - drop it.
            } else if (TOP_PATH.equals(element)) {
                // Registering top path found.
                tops++;
            } else {
                if (tops > 0) {
                    // Merging path element with element corresponding to top
                    // path.
                    tops--;
                } else {
                    // Normal path element found.
                    pathElements.add(0, element);
                }
            }
        }

        // Remaining top paths need to be retained.
        for (int i = 0; i < tops; i++) {
            pathElements.add(0, TOP_PATH);
        }

        return prefix + collectionToDelimitedString(pathElements, FOLDER_SEPARATOR);
    }

    /**
     * Compare two paths after normalization of them.
     * 
     * @param path1
     *            first path for comparison
     * @param path2
     *            second path for comparison
     * @return whether the two paths are equivalent after normalization
     */
    public static boolean pathEquals(String path1, String path2) {
        return cleanPath(path1).equals(cleanPath(path2));
    }

    /**
     * Parse the given <code>localeString</code> value into a {@link Locale}.
     * <p>
     * This is the inverse operation of {@link Locale#toString Locale's
     * toString}.
     * 
     * @param localeString
     *            the locale string, following <code>Locale's</code>
     *            <code>toString()</code> format ("en", "en_UK", etc); also
     *            accepts spaces as separators, as an alternative to underscores
     * @return a corresponding <code>Locale</code> instance
     */
    public static Locale parseLocaleString(String localeString) {
        String[] parts = tokenizeToStringArray(localeString, "_ ", false, false);
        String language = (parts.length > 0 ? parts[0] : "");
        String country = (parts.length > 1 ? parts[1] : "");
        validateLocalePart(language);
        validateLocalePart(country);
        String variant = "";
        if (parts.length >= 2) {
            // There is definitely a variant, and it is everything after the
            // country
            // code sans the separator between the country code and the variant.
            int endIndexOfCountryCode = localeString.indexOf(country) + country.length();
            // Strip off any leading '_' and whitespace, what's left is the
            // variant.
            variant = trimLeadingWhitespace(localeString.substring(endIndexOfCountryCode));
            if (variant.startsWith("_")) {
                variant = trimLeadingCharacter(variant, '_');
            }
        }
        return (language.length() > 0 ? new Locale(language, country, variant) : null);
    }

    private static void validateLocalePart(String localePart) {
        for (int i = 0; i < localePart.length(); i++) {
            char ch = localePart.charAt(i);
            if (ch != '_' && ch != ' ' && !Character.isLetterOrDigit(ch)) {
                throw new IllegalArgumentException(
                        "Locale part \"" + localePart + "\" contains invalid characters");
            }
        }
    }

    /**
     * Determine the RFC 3066 compliant language tag, as used for the HTTP
     * "Accept-Language" header.
     * 
     * @param locale
     *            the Locale to transform to a language tag
     * @return the RFC 3066 compliant language tag as String
     */
    public static String toLanguageTag(Locale locale) {
        return locale.getLanguage() + (hasText(locale.getCountry()) ? "-" + locale.getCountry() : "");
    }

    // ---------------------------------------------------------------------
    // Convenience methods for working with String arrays
    // ---------------------------------------------------------------------

    /**
     * Append the given String to the given String array, returning a new array
     * consisting of the input array contents plus the given String.
     * 
     * @param array
     *            the array to append to (can be <code>null</code>)
     * @param str
     *            the String to append
     * @return the new array (never <code>null</code>)
     */
    public static String[] addStringToArray(String[] array, String str) {
        if (ArrayUtils.isEmpty(array)) {
            return new String[] { str };
        }
        String[] newArr = new String[array.length + 1];
        System.arraycopy(array, 0, newArr, 0, array.length);
        newArr[array.length] = str;
        return newArr;
    }

    /**
     * Concatenate the given String arrays into one, with overlapping array
     * elements included twice.
     * <p>
     * The order of elements in the original arrays is preserved.
     * 
     * @param array1
     *            the first array (can be <code>null</code>)
     * @param array2
     *            the second array (can be <code>null</code>)
     * @return the new array (<code>null</code> if both given arrays were
     *         <code>null</code>)
     */
    public static String[] concatenateStringArrays(String[] array1, String[] array2) {
        if (ArrayUtils.isEmpty(array1)) {
            return array2;
        }
        if (ArrayUtils.isEmpty(array2)) {
            return array1;
        }
        String[] newArr = new String[array1.length + array2.length];
        System.arraycopy(array1, 0, newArr, 0, array1.length);
        System.arraycopy(array2, 0, newArr, array1.length, array2.length);
        return newArr;
    }

    /**
     * Merge the given String arrays into one, with overlapping array elements
     * only included once.
     * <p>
     * The order of elements in the original arrays is preserved (with the
     * exception of overlapping elements, which are only included on their first
     * occurrence).
     * 
     * @param array1
     *            the first array (can be <code>null</code>)
     * @param array2
     *            the second array (can be <code>null</code>)
     * @return the new array (<code>null</code> if both given arrays were
     *         <code>null</code>)
     */
    public static String[] mergeStringArrays(String[] array1, String[] array2) {
        if (ArrayUtils.isEmpty(array1)) {
            return array2;
        }
        if (ArrayUtils.isEmpty(array2)) {
            return array1;
        }
        List<String> result = new ArrayList<String>();
        result.addAll(Arrays.asList(array1));
        for (String str : array2) {
            if (!result.contains(str)) {
                result.add(str);
            }
        }
        return toStringArray(result);
    }

    /**
     * Turn given source String array into sorted array.
     * 
     * @param array
     *            the source array
     * @return the sorted array (never <code>null</code>)
     */
    public static String[] sortStringArray(String[] array) {
        if (ArrayUtils.isEmpty(array)) {
            return new String[0];
        }
        Arrays.sort(array);
        return array;
    }

    /**
     * Copy the given Collection into a String array. The Collection must
     * contain String elements only.
     * 
     * @param collection
     *            the Collection to copy
     * @return the String array (<code>null</code> if the passed-in Collection
     *         was <code>null</code>)
     */
    public static String[] toStringArray(Collection<String> collection) {
        if (collection == null) {
            return null;
        }
        return collection.toArray(new String[collection.size()]);
    }

    /**
     * Copy the given Enumeration into a String array. The Enumeration must
     * contain String elements only.
     * 
     * @param enumeration
     *            the Enumeration to copy
     * @return the String array (<code>null</code> if the passed-in Enumeration
     *         was <code>null</code>)
     */
    public static String[] toStringArray(Enumeration<String> enumeration) {
        if (enumeration == null) {
            return null;
        }
        List<String> list = Collections.list(enumeration);
        return list.toArray(new String[list.size()]);
    }

    /**
     * Trim the elements of the given String array, calling
     * <code>String.trim()</code> on each of them.
     * 
     * @param array
     *            the original String array
     * @return the resulting array (of the same size) with trimmed elements
     */
    public static String[] trimArrayElements(String[] array) {
        if (ArrayUtils.isEmpty(array)) {
            return new String[0];
        }
        String[] result = new String[array.length];
        for (int i = 0; i < array.length; i++) {
            String element = array[i];
            result[i] = (element != null ? element.trim() : null);
        }
        return result;
    }

    /**
     * Remove duplicate Strings from the given array. Also sorts the array, as
     * it uses a TreeSet.
     * 
     * @param array
     *            the String array
     * @return an array without duplicates, in natural sort order
     */
    public static String[] removeDuplicateStrings(String[] array) {
        if (ArrayUtils.isEmpty(array)) {
            return array;
        }
        Set<String> set = new TreeSet<String>();
        for (String element : array) {
            set.add(element);
        }
        return toStringArray(set);
    }

    /**
     * Split a String at the first occurrence of the delimiter. Does not include
     * the delimiter in the result.
     * 
     * @param toSplit
     *            the string to split
     * @param delimiter
     *            to split the string up with
     * @return a two element array with index 0 being before the delimiter, and
     *         index 1 being after the delimiter (neither element includes the
     *         delimiter); or <code>null</code> if the delimiter wasn't found in
     *         the given input String
     */
    public static String[] split(String toSplit, String delimiter) {
        if (!hasLength(toSplit) || !hasLength(delimiter)) {
            return null;
        }
        int offset = toSplit.indexOf(delimiter);
        if (offset < 0) {
            return null;
        }
        String beforeDelimiter = toSplit.substring(0, offset);
        String afterDelimiter = toSplit.substring(offset + delimiter.length());
        return new String[] { beforeDelimiter, afterDelimiter };
    }

    /**
     * Take an array Strings and split each element based on the given
     * delimiter. A <code>Properties</code> instance is then generated, with the
     * left of the delimiter providing the key, and the right of the delimiter
     * providing the value.
     * <p>
     * Will trim both the key and value before adding them to the
     * <code>Properties</code> instance.
     * 
     * @param array
     *            the array to process
     * @param delimiter
     *            to split each element using (typically the equals symbol)
     * @return a <code>Properties</code> instance representing the array
     *         contents, or <code>null</code> if the array to process was null
     *         or empty
     */
    public static Properties splitArrayElementsIntoProperties(String[] array, String delimiter) {
        return splitArrayElementsIntoProperties(array, delimiter, null);
    }

    /**
     * Take an array Strings and split each element based on the given
     * delimiter. A <code>Properties</code> instance is then generated, with the
     * left of the delimiter providing the key, and the right of the delimiter
     * providing the value.
     * <p>
     * Will trim both the key and value before adding them to the
     * <code>Properties</code> instance.
     * 
     * @param array
     *            the array to process
     * @param delimiter
     *            to split each element using (typically the equals symbol)
     * @param charsToDelete
     *            one or more characters to remove from each element prior to
     *            attempting the split operation (typically the quotation mark
     *            symbol), or <code>null</code> if no removal should occur
     * @return a <code>Properties</code> instance representing the array
     *         contents, or <code>null</code> if the array to process was
     *         <code>null</code> or empty
     */
    public static Properties splitArrayElementsIntoProperties(String[] array, String delimiter,
            String charsToDelete) {

        if (ArrayUtils.isEmpty(array)) {
            return null;
        }
        Properties result = new Properties();
        for (String element : array) {
            if (charsToDelete != null) {
                element = deleteAny(element, charsToDelete);
            }
            String[] splittedElement = split(element, delimiter);
            if (splittedElement == null) {
                continue;
            }
            result.setProperty(splittedElement[0].trim(), splittedElement[1].trim());
        }
        return result;
    }

    /**
     * Tokenize the given String into a String array via a StringTokenizer.
     * Trims tokens and omits empty tokens.
     * <p>
     * The given delimiters string is supposed to consist of any number of
     * delimiter characters. Each of those characters can be used to separate
     * tokens. A delimiter is always a single character; for multi-character
     * delimiters, consider using <code>delimitedListToStringArray</code>
     * 
     * @param str
     *            the String to tokenize
     * @param delimiters
     *            the delimiter characters, assembled as String (each of those
     *            characters is individually considered as delimiter).
     * @return an array of the tokens
     * @see java.util.StringTokenizer
     * @see java.lang.String#trim()
     * @see #delimitedListToStringArray
     */
    public static String[] tokenizeToStringArray(String str, String delimiters) {
        return tokenizeToStringArray(str, delimiters, true, true);
    }

    /**
     * Tokenize the given String into a String array via a StringTokenizer.
     * <p>
     * The given delimiters string is supposed to consist of any number of
     * delimiter characters. Each of those characters can be used to separate
     * tokens. A delimiter is always a single character; for multi-character
     * delimiters, consider using <code>delimitedListToStringArray</code>
     * 
     * @param str
     *            the String to tokenize
     * @param delimiters
     *            the delimiter characters, assembled as String (each of those
     *            characters is individually considered as delimiter)
     * @param trimTokens
     *            trim the tokens via String's <code>trim</code>
     * @param ignoreEmptyTokens
     *            omit empty tokens from the result array (only applies to
     *            tokens that are empty after trimming; StringTokenizer will not
     *            consider subsequent delimiters as token in the first place).
     * @return an array of the tokens (<code>null</code> if the input String was
     *         <code>null</code>)
     * @see java.util.StringTokenizer
     * @see java.lang.String#trim()
     * @see #delimitedListToStringArray
     */
    public static String[] tokenizeToStringArray(String str, String delimiters, boolean trimTokens,
            boolean ignoreEmptyTokens) {

        if (str == null) {
            return null;
        }
        StringTokenizer st = new StringTokenizer(str, delimiters);
        List<String> tokens = new ArrayList<String>();
        while (st.hasMoreTokens()) {
            String token = st.nextToken();
            if (trimTokens) {
                token = token.trim();
            }
            if (!ignoreEmptyTokens || token.length() > 0) {
                tokens.add(token);
            }
        }
        return toStringArray(tokens);
    }

    /**
     * Take a String which is a delimited list and convert it to a String array.
     * <p>
     * A single delimiter can consists of more than one character: It will still
     * be considered as single delimiter string, rather than as bunch of
     * potential delimiter characters - in contrast to
     * <code>tokenizeToStringArray</code>.
     * 
     * @param str
     *            the input String
     * @param delimiter
     *            the delimiter between elements (this is a single delimiter,
     *            rather than a bunch individual delimiter characters)
     * @return an array of the tokens in the list
     * @see #tokenizeToStringArray
     */
    public static String[] delimitedListToStringArray(String str, String delimiter) {
        return delimitedListToStringArray(str, delimiter, null);
    }

    /**
     * Take a String which is a delimited list and convert it to a String array.
     * <p>
     * A single delimiter can consists of more than one character: It will still
     * be considered as single delimiter string, rather than as bunch of
     * potential delimiter characters - in contrast to
     * <code>tokenizeToStringArray</code>.
     * 
     * @param str
     *            the input String
     * @param delimiter
     *            the delimiter between elements (this is a single delimiter,
     *            rather than a bunch individual delimiter characters)
     * @param charsToDelete
     *            a set of characters to delete. Useful for deleting unwanted
     *            line breaks: e.g. "\r\n\f" will delete all new lines and line
     *            feeds in a String.
     * @return an array of the tokens in the list
     * @see #tokenizeToStringArray
     */
    public static String[] delimitedListToStringArray(String str, String delimiter, String charsToDelete) {
        if (str == null) {
            return new String[0];
        }
        if (delimiter == null) {
            return new String[] { str };
        }
        List<String> result = new ArrayList<String>();
        if ("".equals(delimiter)) {
            for (int i = 0; i < str.length(); i++) {
                result.add(deleteAny(str.substring(i, i + 1), charsToDelete));
            }
        } else {
            int pos = 0;
            int delPos;
            while ((delPos = str.indexOf(delimiter, pos)) != -1) {
                result.add(deleteAny(str.substring(pos, delPos), charsToDelete));
                pos = delPos + delimiter.length();
            }
            if (str.length() > 0 && pos <= str.length()) {
                // Add rest of String, but not in case of empty input.
                result.add(deleteAny(str.substring(pos), charsToDelete));
            }
        }
        return toStringArray(result);
    }

    /**
     * Convert a CSV list into an array of Strings.
     * 
     * @param str
     *            the input String
     * @return an array of Strings, or the empty array in case of empty input
     */
    public static String[] commaDelimitedListToStringArray(String str) {
        return delimitedListToStringArray(str, ",");
    }

    /**
     * Convenience method to convert a CSV string list to a set. Note that this
     * will suppress duplicates.
     * 
     * @param str
     *            the input String
     * @return a Set of String entries in the list
     */
    public static Set<String> commaDelimitedListToSet(String str) {
        Set<String> set = new TreeSet<String>();
        String[] tokens = commaDelimitedListToStringArray(str);
        for (String token : tokens) {
            set.add(token);
        }
        return set;
    }

    /**
     * Convenience method to return a Collection as a delimited (e.g. CSV)
     * String. E.g. useful for <code>toString()</code> implementations.
     * 
     * @param coll
     *            the Collection to display
     * @param delim
     *            the delimiter to use (probably a ",")
     * @param prefix
     *            the String to start each element with
     * @param suffix
     *            the String to end each element with
     * @return the delimited String
     */
    public static String collectionToDelimitedString(Collection<?> coll, String delim, String prefix,
            String suffix) {
        if (CollectionUtils.isEmpty(coll)) {
            return "";
        }
        StringBuilder sb = new StringBuilder();
        Iterator<?> it = coll.iterator();
        while (it.hasNext()) {
            sb.append(prefix).append(it.next()).append(suffix);
            if (it.hasNext()) {
                sb.append(delim);
            }
        }
        return sb.toString();
    }

    /**
     * Convenience method to return a Collection as a delimited (e.g. CSV)
     * String. E.g. useful for <code>toString()</code> implementations.
     * 
     * @param coll
     *            the Collection to display
     * @param delim
     *            the delimiter to use (probably a ",")
     * @return the delimited String
     */
    public static String collectionToDelimitedString(Collection<?> coll, String delim) {
        return collectionToDelimitedString(coll, delim, "", "");
    }

    /**
     * Convenience method to return a Collection as a CSV String. E.g. useful
     * for <code>toString()</code> implementations.
     * 
     * @param coll
     *            the Collection to display
     * @return the delimited String
     */
    public static String collectionToCommaDelimitedString(Collection<?> coll) {
        return collectionToDelimitedString(coll, ",");
    }

    /**
     * Convenience method to return a String array as a delimited (e.g. CSV)
     * String. E.g. useful for <code>toString()</code> implementations.
     * 
     * @param arr
     *            the array to display
     * @param delim
     *            the delimiter to use (probably a ",")
     * @return the delimited String
     */
    public static String arrayToDelimitedString(Object[] arr, String delim) {
        if (ArrayUtils.isEmpty(arr)) {
            return "";
        }
        if (arr.length == 1) {
            return ObjectUtils.nullSafeToString(arr[0]);
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < arr.length; i++) {
            if (i > 0) {
                sb.append(delim);
            }
            sb.append(arr[i]);
        }
        return sb.toString();
    }

    /**
     * Convenience method to return a String array as a CSV String. E.g. useful
     * for <code>toString()</code> implementations.
     * 
     * @param arr
     *            the array to display
     * @return the delimited String
     */
    public static String arrayToCommaDelimitedString(Object[] arr) {
        return arrayToDelimitedString(arr, ",");
    }

    /**
     * ??
     * 
     * @author mawujun email:16064988@163.com qq:16064988
     * @param input
     * @return
     */
    public static boolean isNumber(String input) {
        Matcher mer = Pattern.compile("^[0-9]+$").matcher(input);
        return mer.find();
    }

    /**
     * <p>
     * Joins the elements of the provided {@code Iterable} into a single String
     * containing the provided elements.
     * </p>
     * 
     * <p>
     * No delimiter is added before or after the list. A {@code null} separator
     * is the same as an empty String ("").
     * </p>
     * 
     * <p>
     * See the examples here: {@link #join(Object[],String)}.
     * </p>
     * 
     * @param iterable
     *            the {@code Iterable} providing the values to join together,
     *            may be null
     * @param separator
     *            the separator character to use, null treated as ""
     * @return the joined String, {@code null} if null iterator input
     * @since 2.3
     */
    public static String join(Iterable<?> iterable, String separator) {
        if (iterable == null) {
            return null;
        }
        return join(iterable.iterator(), separator);
    }

    /**
     * <p>
     * Joins the elements of the provided {@code Iterable} into a single String
     * containing the provided elements.
     * </p>
     * 
     * <p>
     * No delimiter is added before or after the list. Null objects or empty
     * strings within the iteration are represented by empty strings.
     * </p>
     * 
     * <p>
     * See the examples here: {@link #join(Object[],char)}.
     * </p>
     * 
     * @param iterable
     *            the {@code Iterable} providing the values to join together,
     *            may be null
     * @param separator
     *            the separator character to use
     * @return the joined String, {@code null} if null iterator input
     * @since 2.3
     */
    public static String join(Iterable<?> iterable, char separator) {
        if (iterable == null) {
            return null;
        }
        return join(iterable.iterator(), separator);
    }

    /**
     * <p>
     * Joins the elements of the provided {@code Iterator} into a single String
     * containing the provided elements.
     * </p>
     * 
     * <p>
     * No delimiter is added before or after the list. A {@code null} separator
     * is the same as an empty String ("").
     * </p>
     * 
     * <p>
     * See the examples here: {@link #join(Object[],String)}.
     * </p>
     * 
     * @param iterator
     *            the {@code Iterator} of values to join together, may be null
     * @param separator
     *            the separator character to use, null treated as ""
     * @return the joined String, {@code null} if null iterator input
     */
    public static String join(Iterator<?> iterator, String separator) {

        // handle null, zero and one elements before building a buffer
        if (iterator == null) {
            return null;
        }
        if (!iterator.hasNext()) {
            return EMPTY;
        }
        Object first = iterator.next();
        if (!iterator.hasNext()) {
            return ObjectUtils.toString(first);
        }

        // two or more elements
        StringBuilder buf = new StringBuilder(256); // Java default is 16,
        // probably too small
        if (first != null) {
            buf.append(first);
        }

        while (iterator.hasNext()) {
            if (separator != null) {
                buf.append(separator);
            }
            Object obj = iterator.next();
            if (obj != null) {
                buf.append(obj);
            }
        }
        return buf.toString();
    }

    // Trim
    // -----------------------------------------------------------------------
    /**
     * <p>
     * Removes control characters (char &lt;= 32) from both ends of this String,
     * handling {@code null} by returning {@code null}.
     * </p>
     * 
     * <p>
     * The String is trimmed using {@link String#trim()}. Trim removes start and
     * end characters &lt;= 32. To strip whitespace use {@link #strip(String)}.
     * </p>
     * 
     * <p>
     * To trim your choice of characters, use the {@link #strip(String, String)}
     * methods.
     * </p>
     * 
     * <pre>
     * StringUtils.trim(null)          = null
     * StringUtils.trim("")            = ""
     * StringUtils.trim("     ")       = ""
     * StringUtils.trim("abc")         = "abc"
     * StringUtils.trim("    abc    ") = "abc"
     * </pre>
     * 
     * @param str
     *            the String to be trimmed, may be null
     * @return the trimmed string, {@code null} if null String input
     */
    public static String trim(String str) {
        return str == null ? null : str.trim();
    }

    /**
     * <p>
     * Removes control characters (char &lt;= 32) from both ends of this String
     * returning {@code null} if the String is empty ("") after the trim or if
     * it is {@code null}.
     * 
     * <p>
     * The String is trimmed using {@link String#trim()}. Trim removes start and
     * end characters &lt;= 32. To strip whitespace use
     * {@link #stripToNull(String)}.
     * </p>
     * 
     * <pre>
     * StringUtils.trimToNull(null)          = null
     * StringUtils.trimToNull("")            = null
     * StringUtils.trimToNull("     ")       = null
     * StringUtils.trimToNull("abc")         = "abc"
     * StringUtils.trimToNull("    abc    ") = "abc"
     * </pre>
     * 
     * @param str
     *            the String to be trimmed, may be null
     * @return the trimmed String, {@code null} if only chars &lt;= 32, empty or
     *         null String input
     * @since 2.0
     */
    public static String trimToNull(String str) {
        String ts = trim(str);
        return isEmpty(ts) ? null : ts;
    }

    /**
     * <p>
     * Removes control characters (char &lt;= 32) from both ends of this String
     * returning an empty String ("") if the String is empty ("") after the trim
     * or if it is {@code null}.
     * 
     * <p>
     * The String is trimmed using {@link String#trim()}. Trim removes start and
     * end characters &lt;= 32. To strip whitespace use
     * {@link #stripToEmpty(String)}.
     * </p>
     * 
     * <pre>
     * StringUtils.trimToEmpty(null)          = ""
     * StringUtils.trimToEmpty("")            = ""
     * StringUtils.trimToEmpty("     ")       = ""
     * StringUtils.trimToEmpty("abc")         = "abc"
     * StringUtils.trimToEmpty("    abc    ") = "abc"
     * </pre>
     * 
     * @param str
     *            the String to be trimmed, may be null
     * @return the trimmed String, or an empty String if {@code null} input
     * @since 2.0
     */
    public static String trimToEmpty(String str) {
        return str == null ? EMPTY : str.trim();
    }

    // Stripping
    // -----------------------------------------------------------------------
    /**
     * <p>
     * Strips whitespace from the start and end of a String.
     * </p>
     * 
     * <p>
     * This is similar to {@link #trim(String)} but removes whitespace.
     * Whitespace is defined by {@link Character#isWhitespace(char)}.
     * </p>
     * 
     * <p>
     * A {@code null} input String returns {@code null}.
     * </p>
     * 
     * <pre>
     * StringUtils.strip(null)     = null
     * StringUtils.strip("")       = ""
     * StringUtils.strip("   ")    = ""
     * StringUtils.strip("abc")    = "abc"
     * StringUtils.strip("  abc")  = "abc"
     * StringUtils.strip("abc  ")  = "abc"
     * StringUtils.strip(" abc ")  = "abc"
     * StringUtils.strip(" ab c ") = "ab c"
     * </pre>
     * 
     * @param str
     *            the String to remove whitespace from, may be null
     * @return the stripped String, {@code null} if null String input
     */
    public static String strip(String str) {
        return strip(str, null);
    }

    /**
     * <p>
     * Strips whitespace from the start and end of a String returning
     * {@code null} if the String is empty ("") after the strip.
     * </p>
     * 
     * <p>
     * This is similar to {@link #trimToNull(String)} but removes whitespace.
     * Whitespace is defined by {@link Character#isWhitespace(char)}.
     * </p>
     * 
     * <pre>
     * StringUtils.stripToNull(null)     = null
     * StringUtils.stripToNull("")       = null
     * StringUtils.stripToNull("   ")    = null
     * StringUtils.stripToNull("abc")    = "abc"
     * StringUtils.stripToNull("  abc")  = "abc"
     * StringUtils.stripToNull("abc  ")  = "abc"
     * StringUtils.stripToNull(" abc ")  = "abc"
     * StringUtils.stripToNull(" ab c ") = "ab c"
     * </pre>
     * 
     * @param str
     *            the String to be stripped, may be null
     * @return the stripped String, {@code null} if whitespace, empty or null
     *         String input
     * @since 2.0
     */
    public static String stripToNull(String str) {
        if (str == null) {
            return null;
        }
        str = strip(str, null);
        return str.length() == 0 ? null : str;
    }

    /**
     * <p>
     * Strips whitespace from the start and end of a String returning an empty
     * String if {@code null} input.
     * </p>
     * 
     * <p>
     * This is similar to {@link #trimToEmpty(String)} but removes whitespace.
     * Whitespace is defined by {@link Character#isWhitespace(char)}.
     * </p>
     * 
     * <pre>
     * StringUtils.stripToEmpty(null)     = ""
     * StringUtils.stripToEmpty("")       = ""
     * StringUtils.stripToEmpty("   ")    = ""
     * StringUtils.stripToEmpty("abc")    = "abc"
     * StringUtils.stripToEmpty("  abc")  = "abc"
     * StringUtils.stripToEmpty("abc  ")  = "abc"
     * StringUtils.stripToEmpty(" abc ")  = "abc"
     * StringUtils.stripToEmpty(" ab c ") = "ab c"
     * </pre>
     * 
     * @param str
     *            the String to be stripped, may be null
     * @return the trimmed String, or an empty String if {@code null} input
     * @since 2.0
     */
    public static String stripToEmpty(String str) {
        return str == null ? EMPTY : strip(str, null);
    }

    /**
     * <p>
     * Strips any of a set of characters from the start and end of a String.
     * This is similar to {@link String#trim()} but allows the characters to be
     * stripped to be controlled.
     * </p>
     * 
     * <p>
     * A {@code null} input String returns {@code null}. An empty string ("")
     * input returns the empty string.
     * </p>
     * 
     * <p>
     * If the stripChars String is {@code null}, whitespace is stripped as
     * defined by {@link Character#isWhitespace(char)}. Alternatively use
     * {@link #strip(String)}.
     * </p>
     * 
     * <pre>
     * StringUtils.strip(null, *)          = null
     * StringUtils.strip("", *)            = ""
     * StringUtils.strip("abc", null)      = "abc"
     * StringUtils.strip("  abc", null)    = "abc"
     * StringUtils.strip("abc  ", null)    = "abc"
     * StringUtils.strip(" abc ", null)    = "abc"
     * StringUtils.strip("  abcyx", "xyz") = "  abc"
     * </pre>
     * 
     * @param str
     *            the String to remove characters from, may be null
     * @param stripChars
     *            the characters to remove, null treated as whitespace
     * @return the stripped String, {@code null} if null String input
     */
    public static String strip(String str, String stripChars) {
        if (isEmpty(str)) {
            return str;
        }
        str = stripStart(str, stripChars);
        return stripEnd(str, stripChars);
    }

    /**
     * <p>
     * Strips any of a set of characters from the start of a String.
     * </p>
     * 
     * <p>
     * A {@code null} input String returns {@code null}. An empty string ("")
     * input returns the empty string.
     * </p>
     * 
     * <p>
     * If the stripChars String is {@code null}, whitespace is stripped as
     * defined by {@link Character#isWhitespace(char)}.
     * </p>
     * 
     * <pre>
     * StringUtils.stripStart(null, *)          = null
     * StringUtils.stripStart("", *)            = ""
     * StringUtils.stripStart("abc", "")        = "abc"
     * StringUtils.stripStart("abc", null)      = "abc"
     * StringUtils.stripStart("  abc", null)    = "abc"
     * StringUtils.stripStart("abc  ", null)    = "abc  "
     * StringUtils.stripStart(" abc ", null)    = "abc "
     * StringUtils.stripStart("yxabc  ", "xyz") = "abc  "
     * </pre>
     * 
     * @param str
     *            the String to remove characters from, may be null
     * @param stripChars
     *            the characters to remove, null treated as whitespace
     * @return the stripped String, {@code null} if null String input
     */
    public static String stripStart(String str, String stripChars) {
        int strLen;
        if (str == null || (strLen = str.length()) == 0) {
            return str;
        }
        int start = 0;
        if (stripChars == null) {
            while (start != strLen && Character.isWhitespace(str.charAt(start))) {
                start++;
            }
        } else if (stripChars.length() == 0) {
            return str;
        } else {
            while (start != strLen && stripChars.indexOf(str.charAt(start)) != INDEX_NOT_FOUND) {
                start++;
            }
        }
        return str.substring(start);
    }

    /**
     * <p>
     * Strips any of a set of characters from the end of a String.
     * </p>
     * 
     * <p>
     * A {@code null} input String returns {@code null}. An empty string ("")
     * input returns the empty string.
     * </p>
     * 
     * <p>
     * If the stripChars String is {@code null}, whitespace is stripped as
     * defined by {@link Character#isWhitespace(char)}.
     * </p>
     * 
     * <pre>
     * StringUtils.stripEnd(null, *)          = null
     * StringUtils.stripEnd("", *)            = ""
     * StringUtils.stripEnd("abc", "")        = "abc"
     * StringUtils.stripEnd("abc", null)      = "abc"
     * StringUtils.stripEnd("  abc", null)    = "  abc"
     * StringUtils.stripEnd("abc  ", null)    = "abc"
     * StringUtils.stripEnd(" abc ", null)    = " abc"
     * StringUtils.stripEnd("  abcyx", "xyz") = "  abc"
     * StringUtils.stripEnd("120.00", ".0")   = "12"
     * </pre>
     * 
     * @param str
     *            the String to remove characters from, may be null
     * @param stripChars
     *            the set of characters to remove, null treated as whitespace
     * @return the stripped String, {@code null} if null String input
     */
    public static String stripEnd(String str, String stripChars) {
        int end;
        if (str == null || (end = str.length()) == 0) {
            return str;
        }

        if (stripChars == null) {
            while (end != 0 && Character.isWhitespace(str.charAt(end - 1))) {
                end--;
            }
        } else if (stripChars.length() == 0) {
            return str;
        } else {
            while (end != 0 && stripChars.indexOf(str.charAt(end - 1)) != INDEX_NOT_FOUND) {
                end--;
            }
        }
        return str.substring(0, end);
    }

    // StripAll
    // -----------------------------------------------------------------------
    /**
     * <p>
     * Strips whitespace from the start and end of every String in an array.
     * Whitespace is defined by {@link Character#isWhitespace(char)}.
     * </p>
     * 
     * <p>
     * A new array is returned each time, except for length zero. A {@code null}
     * array will return {@code null}. An empty array will return itself. A
     * {@code null} array entry will be ignored.
     * </p>
     * 
     * <pre>
     * StringUtils.stripAll(null)             = null
     * StringUtils.stripAll([])               = []
     * StringUtils.stripAll(["abc", "  abc"]) = ["abc", "abc"]
     * StringUtils.stripAll(["abc  ", null])  = ["abc", null]
     * </pre>
     * 
     * @param strs
     *            the array to remove whitespace from, may be null
     * @return the stripped Strings, {@code null} if null array input
     */
    public static String[] stripAll(String... strs) {
        return stripAll(strs, null);
    }

    /**
     * <p>
     * Strips any of a set of characters from the start and end of every String
     * in an array.
     * </p>
     * Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
     * 
     * <p>
     * A new array is returned each time, except for length zero. A {@code null}
     * array will return {@code null}. An empty array will return itself. A
     * {@code null} array entry will be ignored. A {@code null} stripChars will
     * strip whitespace as defined by {@link Character#isWhitespace(char)}.
     * </p>
     * 
     * <pre>
     * StringUtils.stripAll(null, *)                = null
     * StringUtils.stripAll([], *)                  = []
     * StringUtils.stripAll(["abc", "  abc"], null) = ["abc", "abc"]
     * StringUtils.stripAll(["abc  ", null], null)  = ["abc", null]
     * StringUtils.stripAll(["abc  ", null], "yz")  = ["abc  ", null]
     * StringUtils.stripAll(["yabcz", null], "yz")  = ["abc", null]
     * </pre>
     * 
     * @param strs
     *            the array to remove characters from, may be null
     * @param stripChars
     *            the characters to remove, null treated as whitespace
     * @return the stripped Strings, {@code null} if null array input
     */
    public static String[] stripAll(String[] strs, String stripChars) {
        int strsLen;
        if (strs == null || (strsLen = strs.length) == 0) {
            return strs;
        }
        String[] newArr = new String[strsLen];
        for (int i = 0; i < strsLen; i++) {
            newArr[i] = strip(strs[i], stripChars);
        }
        return newArr;
    }

}