Java tutorial
/* * Copyright 2002-2008 the original author or authors. * * Licensed 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 cn.remex.core.util; import java.util.*; /** * ?? * Miscellaneous {@link String} utility methods. * * <p>Mainly for internal use within the framework; consider * <a href="http://jakarta.apache.org/commons/lang/">Jakarta's Commons Lang</a> * for a more comprehensive suite of String utilities. * * <p>This class delivers some simple functionality that should really * be provided by the core Java <code>String</code> and {@link StringBuffer} * classes, such as the ability to {@link #replace} all occurrences of a given * substring in a target string. It also provides easy-to-use methods to convert * between delimited strings, such as CSV strings, and collections and arrays. * * @author Rod Johnson * @author Juergen Hoeller * @author Keith Donald * @author Rob Harrop * @author Rick Evans * @since 16 April 2001 * @see org.apache.commons.lang.StringUtils */ public abstract class StringUtils { private static final String CURRENT_PATH = "."; private static final char EXTENSION_SEPARATOR = '.'; private static final String FOLDER_SEPARATOR = "/"; private static final String TOP_PATH = ".."; private static final String WINDOWS_FOLDER_SEPARATOR = "\\"; //--------------------------------------------------------------------- // General convenience methods for working with Strings //--------------------------------------------------------------------- /** * ????string * 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>) ??null */ public static String[] addStringToArray(final String[] array, final String str) { if (ObjectUtils.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; } /** * * 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(final String path, final 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; } } /** * ??string"," * 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 string */ public static String arrayToCommaDelimitedString(final Object[] arr) { return arrayToDelimitedString(arr, ","); } /** * ??string? * 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(final Object[] arr, final String delim) { if (ObjectUtils.isEmpty(arr)) { return ""; } StringBuffer sb = new StringBuffer(); for (int i = 0; i < arr.length; i++) { if (i > 0) { sb.append(delim); } sb.append(arr[i]); } return sb.toString(); } /** * 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(final String str) { return changeFirstCharacterCase(str, true); } /** * * 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(final 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); } /** * ???"," * 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(final Collection<String> coll) { return collectionToDelimitedString(coll, ","); } /** * ???? * 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 ??string */ public static String collectionToDelimitedString(final Collection<String> coll, final String delim) { return collectionToDelimitedString(coll, delim, "", ""); } /** * ???string,?? * 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 ??string */ public static String collectionToDelimitedString(final Collection<String> coll, final String delim, final String prefix, final String suffix) { if (CollectionUtils.isEmpty(coll)) { return ""; } StringBuffer sb = new StringBuffer(); Iterator<String> it = coll.iterator(); while (it.hasNext()) { sb.append(prefix).append(it.next()).append(suffix); if (it.hasNext()) { sb.append(delim); } } return sb.toString(); } /** * string??set??? * Convenience method to convert a CSV string list to a set. * Note that this will suppress duplicates. * @param str the input String ??string * @return a Set of String entries in the list ? */ public static Set<String> commaDelimitedListToSet(final String str) { Set<String> set = new TreeSet<String>(); String[] tokens = commaDelimitedListToStringArray(str); for (String token : tokens) { set.add(token); } return set; } /** * list??string * Convert a CSV list into an array of Strings. * @param str the input String ??string * @return an array of Strings, or the empty array in case of empty input ? */ public static String[] commaDelimitedListToStringArray(final String str) { return delimitedListToStringArray(str, ","); } /** * ???? * 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(final String[] array1, final String[] array2) { if (ObjectUtils.isEmpty(array1)) { return array2; } if (ObjectUtils.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; } /** * ????? * 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(final 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(final String str) { return containsWhitespace((CharSequence) str); } /** * ? * Count the occurrences of the substring in string s. * @param str string to search in. Return 0 if this is null. ? 0 * @param sub string to search for. Return 0 if this is null. 0 */ public static int countOccurrencesOf(final String str, final String sub) { if (str == null || sub == null || str.length() == 0 || sub.length() == 0) { return 0; } int count = 0, pos = 0, idx = 0; while ((idx = str.indexOf(sub, pos)) != -1) { ++count; pos = idx + sub.length(); } return count; } /** * ? * 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(final String inString, final 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(final String inString, final String charsToDelete) { if (!hasLength(inString) || !hasLength(charsToDelete)) { return inString; } StringBuffer out = new StringBuffer(); for (int i = 0; i < inString.length(); i++) { char c = inString.charAt(i); if (charsToDelete.indexOf(c) == -1) { out.append(c); } } return out.toString(); } /** * * 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(final String str, final 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(final String str, final String delimiter, final 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 = 0; 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); } //--------------------------------------------------------------------- // Convenience methods for working with formatted Strings //--------------------------------------------------------------------- /** * ??? * 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(final String str, final 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); } /** * ??? * 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 ??null */ public static String getFilename(final 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 ??null */ public static String getFilenameExtension(final String path) { if (path == null) { return null; } int sepIndex = path.lastIndexOf(EXTENSION_SEPARATOR); return sepIndex != -1 ? path.substring(sepIndex + 1) : null; } /** * ??null?0??true * 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 ??0 true * @see #hasText(String) */ public static boolean hasLength(final CharSequence str) { return str != null && str.length() > 0; } /** * ?null?0??true * 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 ?true * @see #hasLength(CharSequence) */ public static boolean hasLength(final String str) { return hasLength((CharSequence) str); } /** * ??:?string?null0???true * 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(final 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; } /** * ?:?string?null0???true * 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(final String str) { return hasText((CharSequence) str); } /** * ????? * 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 occurence). * @param array1 the first array (can be <code>null</code>) 1 * @param array2 the second array (can be <code>null</code>) 2 * @return the new array (<code>null</code> if both given arrays were <code>null</code>)?? */ public static String[] mergeStringArrays(final String[] array1, final String[] array2) { if (ObjectUtils.isEmpty(array1)) { return array2; } if (ObjectUtils.isEmpty(array2)) { return array1; } List<String> result = new ArrayList<String>(); result.addAll(Arrays.asList(array1)); for (String element : array2) { String str = element; if (!result.contains(str)) { result.add(str); } } return toStringArray(result); } /** * * Parse the given <code>localeString</code> 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(final String localeString) { String[] parts = tokenizeToStringArray(localeString, "_ ", false, false); String language = parts.length > 0 ? parts[0] : ""; String country = parts.length > 1 ? parts[1] : ""; 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; } /** * ? * Compare two paths after normalization of them. * @param path1 first path for comparison 1 * @param path2 second path for comparison 2 * @return whether the two paths are equivalent after normalization */ public static boolean pathEquals(final String path1, final String path2) { return cleanPath(path1).equals(cleanPath(path2)); } /** * ?? * 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> ?? null */ public static String quote(final 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(final Object obj) { return obj instanceof String ? quote((String) obj) : obj; } /** * ??string?? * 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(final String[] array) { if (ObjectUtils.isEmpty(array)) { return array; } Set<String> set = new TreeSet<String>(); for (String element : array) { set.add(element); } return toStringArray(set); } /** * ????? * 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(final String inString, final String oldPattern, final String newPattern) { if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null) { return inString; } StringBuffer sbuf = new StringBuffer(); // output StringBuffer we'll build up int pos = 0; // our position in the old string int index = inString.indexOf(oldPattern); // the param of an occurrence we've found, or -1 int patLen = oldPattern.length(); while (index >= 0) { sbuf.append(inString.substring(pos, index)); sbuf.append(newPattern); pos = index + patLen; index = inString.indexOf(oldPattern, pos); } sbuf.append(inString.substring(pos)); // remember to append any characters to the right of a match return sbuf.toString(); } /** * ?? * 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(final String[] array) { if (ObjectUtils.isEmpty(array)) { return new String[0]; } Arrays.sort(array); return array; } //--------------------------------------------------------------------- // Convenience methods for working with String arrays //--------------------------------------------------------------------- /** * ?? * 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 ,???? (???);null * a two element array with param 0 being before the delimiter, and * param 1 being after the delimiter (neither element includes the delimite * or <code>null</code> if the delimiter wasn't found in the given input String */ public static String[] split(final String toSplit, final 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 null */ public static Properties splitArrayElementsIntoProperties(final String[] array, final 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(final String[] array, final String delimiter, final String charsToDelete) { if (ObjectUtils.isEmpty(array)) { return null; } Properties result = new Properties(); for (String element2 : array) { String element = element2; if (charsToDelete != null) { element = deleteAny(element2, charsToDelete); } String[] splittedElement = split(element, delimiter); if (splittedElement == null) { continue; } result.setProperty(splittedElement[0].trim(), splittedElement[1].trim()); } return result; } /** * ????,? * 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(final String str, final 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); } /** * ???? * 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 ??null */ public static String stripFilenameExtension(final String path) { if (path == null) { return null; } int sepIndex = path.lastIndexOf(EXTENSION_SEPARATOR); return sepIndex != -1 ? path.substring(0, sepIndex) : path; } /** * ??????? * Test whether the given string matches the given substring * at the given param. * @param str the original string (or StringBuffer) ? * @param index the param in the original string to start matching against ? * @param substring the substring to match at the given param ?? */ public static boolean substringMatch(final CharSequence str, final int index, final 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; } /** * * 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(final String str, final 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(final String str, final String delimiters, final boolean trimTokens, final 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); } /** * HTTP RFC 3306?? * 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 RFC 3306?? */ public static String toLanguageTag(final Locale locale) { return locale.getLanguage() + (hasText(locale.getCountry()) ? "-" + locale.getCountry() : ""); } /** * ???????string * 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>) nullnull */ public static String[] toStringArray(final 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>) nullnull */ public static String[] toStringArray(final Enumeration<?> enumeration) { if (enumeration == null) { return null; } List<?> list = Collections.list(enumeration); return list.toArray(new String[list.size()]); } /** * * 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(final String str) { if (!hasLength(str)) { return str; } StringBuffer buf = new StringBuffer(str); int index = 0; while (buf.length() > index) { if (Character.isWhitespace(buf.charAt(index))) { buf.deleteCharAt(index); } else { index++; } } return buf.toString(); } /** * ?<code>String.trim()</code> * 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(final String[] array) { if (ObjectUtils.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; } /** * * 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(final String str, final char leadingCharacter) { if (!hasLength(str)) { return str; } StringBuffer buf = new StringBuffer(str); while (buf.length() > 0 && buf.charAt(0) == leadingCharacter) { buf.deleteCharAt(0); } return buf.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(final String str) { if (!hasLength(str)) { return str; } StringBuffer buf = new StringBuffer(str); while (buf.length() > 0 && Character.isWhitespace(buf.charAt(0))) { buf.deleteCharAt(0); } return buf.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(final String str, final char trailingCharacter) { if (!hasLength(str)) { return str; } StringBuffer buf = new StringBuffer(str); while (buf.length() > 0 && buf.charAt(buf.length() - 1) == trailingCharacter) { buf.deleteCharAt(buf.length() - 1); } return buf.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(final String str) { if (!hasLength(str)) { return str; } StringBuffer buf = new StringBuffer(str); while (buf.length() > 0 && Character.isWhitespace(buf.charAt(buf.length() - 1))) { buf.deleteCharAt(buf.length() - 1); } return buf.toString(); } /** * * 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(final String str) { if (!hasLength(str)) { return str; } StringBuffer buf = new StringBuffer(str); while (buf.length() > 0 && Character.isWhitespace(buf.charAt(0))) { buf.deleteCharAt(0); } while (buf.length() > 0 && Character.isWhitespace(buf.charAt(buf.length() - 1))) { buf.deleteCharAt(buf.length() - 1); } return buf.toString(); } /** * TODO * ?string?????? * 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> ?string?null * @return the uncapitalized String, <code>null</code> if null stringnullnull */ public static String uncapitalize(final String str) { return changeFirstCharacterCase(str, false); } /** * 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(final 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(final String qualifiedName, final char separator) { return qualifiedName.substring(qualifiedName.lastIndexOf(separator) + 1); } private static String changeFirstCharacterCase(final String str, final boolean capitalize) { if (str == null || str.length() == 0) { return str; } StringBuffer buf = new StringBuffer(str.length()); if (capitalize) { buf.append(Character.toUpperCase(str.charAt(0))); } else { buf.append(Character.toLowerCase(str.charAt(0))); } buf.append(str.substring(1)); return buf.toString(); } }