Java tutorial
/* * 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 <= 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 <= 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 <= 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 <= 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 <= 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 <= 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 <= 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; } }