一、前言
关于apace的shiro源码包org.apache.shiro.util.StringUtils字符串工具类,进行字符串判断是否有文本hasText、对象数组转字符串toString、集合转字符串数组toStringArray、分隔内容行为字符串数组splitKeyValue等。
二、源码说明
package org.apache.shiro.util;@b@@b@import java.text.ParseException;@b@import java.util.*;@b@ @b@public class StringUtils {@b@@b@ @b@ public static final String EMPTY_STRING = "";@b@@b@ /**@b@ * Constant representing the default delimiter character (comma), equal to <code>','</code>@b@ */@b@ public static final char DEFAULT_DELIMITER_CHAR = ',';@b@@b@ /**@b@ * Constant representing the default quote character (double quote), equal to '"'</code>@b@ */@b@ public static final char DEFAULT_QUOTE_CHAR = '"';@b@@b@ /**@b@ * Check whether the given String has actual text.@b@ * More specifically, returns <code>true</code> if the string not <code>null</code>,@b@ * its length is greater than 0, and it contains at least one non-whitespace character.@b@ * <p/>@b@ * <code>StringUtils.hasText(null) == false<br/>@b@ * StringUtils.hasText("") == false<br/>@b@ * StringUtils.hasText(" ") == false<br/>@b@ * StringUtils.hasText("12345") == true<br/>@b@ * StringUtils.hasText(" 12345 ") == true</code>@b@ * <p/>@b@ * <p>Copied from the Spring Framework while retaining all license, copyright and author information.@b@ *@b@ * @param str the String to check (may be <code>null</code>)@b@ * @return <code>true</code> if the String is not <code>null</code>, its length is@b@ * greater than 0, and it does not contain whitespace only@b@ * @see java.lang.Character#isWhitespace@b@ */@b@ public static boolean hasText(String str) {@b@ if (!hasLength(str)) {@b@ return false;@b@ }@b@ int strLen = str.length();@b@ for (int i = 0; i < strLen; i++) {@b@ if (!Character.isWhitespace(str.charAt(i))) {@b@ return true;@b@ }@b@ }@b@ return false;@b@ }@b@@b@ /**@b@ * Check that the given String is neither <code>null</code> nor of length 0.@b@ * Note: Will return <code>true</code> for a String that purely consists of whitespace.@b@ * <p/>@b@ * <code>StringUtils.hasLength(null) == false<br/>@b@ * StringUtils.hasLength("") == false<br/>@b@ * StringUtils.hasLength(" ") == true<br/>@b@ * StringUtils.hasLength("Hello") == true</code>@b@ * <p/>@b@ * Copied from the Spring Framework while retaining all license, copyright and author information.@b@ *@b@ * @param str the String to check (may be <code>null</code>)@b@ * @return <code>true</code> if the String is not null and has length@b@ * @see #hasText(String)@b@ */@b@ public static boolean hasLength(String str) {@b@ return (str != null && str.length() > 0);@b@ }@b@@b@@b@ /**@b@ * Test if the given String starts with the specified prefix,@b@ * ignoring upper/lower case.@b@ * <p/>@b@ * <p>Copied from the Spring Framework while retaining all license, copyright and author information.@b@ *@b@ * @param str the String to check@b@ * @param prefix the prefix to look for@b@ * @return <code>true</code> starts with the specified prefix (ignoring case), <code>false</code> if it does not.@b@ * @see java.lang.String#startsWith@b@ */@b@ public static boolean startsWithIgnoreCase(String str, String prefix) {@b@ if (str == null || prefix == null) {@b@ return false;@b@ }@b@ if (str.startsWith(prefix)) {@b@ return true;@b@ }@b@ if (str.length() < prefix.length()) {@b@ return false;@b@ }@b@ String lcStr = str.substring(0, prefix.length()).toLowerCase();@b@ String lcPrefix = prefix.toLowerCase();@b@ return lcStr.equals(lcPrefix);@b@ }@b@@b@ /**@b@ * Returns a 'cleaned' representation of the specified argument. 'Cleaned' is defined as the following:@b@ * <p/>@b@ * <ol>@b@ * <li>If the specified <code>String</code> is <code>null</code>, return <code>null</code></li>@b@ * <li>If not <code>null</code>, {@link String#trim() trim()} it.</li>@b@ * <li>If the trimmed string is equal to the empty String (i.e. ""), return <code>null</code></li>@b@ * <li>If the trimmed string is not the empty string, return the trimmed version</li>.@b@ * </ol>@b@ * <p/>@b@ * Therefore this method always ensures that any given string has trimmed text, and if it doesn't, <code>null</code>@b@ * is returned.@b@ *@b@ * @param in the input String to clean.@b@ * @return a populated-but-trimmed String or <code>null</code> otherwise@b@ */@b@ public static String clean(String in) {@b@ String out = in;@b@@b@ if (in != null) {@b@ out = in.trim();@b@ if (out.equals(EMPTY_STRING)) {@b@ out = null;@b@ }@b@ }@b@@b@ return out;@b@ }@b@@b@ /**@b@ * Returns the specified array as a comma-delimited (',') string.@b@ *@b@ * @param array the array whose contents will be converted to a string.@b@ * @return the array's contents as a comma-delimited (',') string.@b@ * @since 1.0@b@ */@b@ public static String toString(Object[] array) {@b@ return toDelimitedString(array, ",");@b@ }@b@@b@ /**@b@ * Returns the array's contents as a string, with each element delimited by the specified@b@ * {@code delimiter} argument. Useful for {@code toString()} implementations and log messages.@b@ *@b@ * @param array the array whose contents will be converted to a string@b@ * @param delimiter the delimiter to use between each element@b@ * @return a single string, delimited by the specified {@code delimiter}.@b@ * @since 1.0@b@ */@b@ public static String toDelimitedString(Object[] array, String delimiter) {@b@ if (array == null || array.length == 0) {@b@ return EMPTY_STRING;@b@ }@b@ StringBuilder sb = new StringBuilder();@b@ for (int i = 0; i < array.length; i++) {@b@ if (i > 0) {@b@ sb.append(delimiter);@b@ }@b@ sb.append(array[i]);@b@ }@b@ return sb.toString();@b@ }@b@@b@ /**@b@ * Returns the collection's contents as a string, with each element delimited by the specified@b@ * {@code delimiter} argument. Useful for {@code toString()} implementations and log messages.@b@ *@b@ * @param c the collection whose contents will be converted to a string@b@ * @param delimiter the delimiter to use between each element@b@ * @return a single string, delimited by the specified {@code delimiter}.@b@ * @since 1.2@b@ */@b@ public static String toDelimitedString(Collection c, String delimiter) {@b@ if (c == null || c.isEmpty()) {@b@ return EMPTY_STRING;@b@ }@b@ return join(c.iterator(), delimiter);@b@ }@b@@b@ /**@b@ * Tokenize the given String into a String array via a StringTokenizer.@b@ * Trims tokens and omits empty tokens.@b@ * <p>The given delimiters string is supposed to consist of any number of@b@ * delimiter characters. Each of those characters can be used to separate@b@ * tokens. A delimiter is always a single character; for multi-character@b@ * delimiters, consider using <code>delimitedListToStringArray</code>@b@ * <p/>@b@ * <p>Copied from the Spring Framework while retaining all license, copyright and author information.@b@ *@b@ * @param str the String to tokenize@b@ * @param delimiters the delimiter characters, assembled as String@b@ * (each of those characters is inpidually considered as delimiter).@b@ * @return an array of the tokens@b@ * @see java.util.StringTokenizer@b@ * @see java.lang.String#trim()@b@ */@b@ public static String[] tokenizeToStringArray(String str, String delimiters) {@b@ return tokenizeToStringArray(str, delimiters, true, true);@b@ }@b@@b@ /**@b@ * Tokenize the given String into a String array via a StringTokenizer.@b@ * <p>The given delimiters string is supposed to consist of any number of@b@ * delimiter characters. Each of those characters can be used to separate@b@ * tokens. A delimiter is always a single character; for multi-character@b@ * delimiters, consider using <code>delimitedListToStringArray</code>@b@ * <p/>@b@ * <p>Copied from the Spring Framework while retaining all license, copyright and author information.@b@ *@b@ * @param str the String to tokenize@b@ * @param delimiters the delimiter characters, assembled as String@b@ * (each of those characters is inpidually considered as delimiter)@b@ * @param trimTokens trim the tokens via String's <code>trim</code>@b@ * @param ignoreEmptyTokens omit empty tokens from the result array@b@ * (only applies to tokens that are empty after trimming; StringTokenizer@b@ * will not consider subsequent delimiters as token in the first place).@b@ * @return an array of the tokens (<code>null</code> if the input String@b@ * was <code>null</code>)@b@ * @see java.util.StringTokenizer@b@ * @see java.lang.String#trim()@b@ */@b@ @SuppressWarnings({"unchecked"})@b@ public static String[] tokenizeToStringArray(@b@ String str, String delimiters, boolean trimTokens, boolean ignoreEmptyTokens) {@b@@b@ if (str == null) {@b@ return null;@b@ }@b@ StringTokenizer st = new StringTokenizer(str, delimiters);@b@ List tokens = new ArrayList();@b@ while (st.hasMoreTokens()) {@b@ String token = st.nextToken();@b@ if (trimTokens) {@b@ token = token.trim();@b@ }@b@ if (!ignoreEmptyTokens || token.length() > 0) {@b@ tokens.add(token);@b@ }@b@ }@b@ return toStringArray(tokens);@b@ }@b@@b@ /**@b@ * Copy the given Collection into a String array.@b@ * The Collection must contain String elements only.@b@ * <p/>@b@ * <p>Copied from the Spring Framework while retaining all license, copyright and author information.@b@ *@b@ * @param collection the Collection to copy@b@ * @return the String array (<code>null</code> if the passed-in@b@ * Collection was <code>null</code>)@b@ */@b@ @SuppressWarnings({"unchecked"})@b@ public static String[] toStringArray(Collection collection) {@b@ if (collection == null) {@b@ return null;@b@ }@b@ return (String[]) collection.toArray(new String[collection.size()]);@b@ }@b@@b@ public static String[] splitKeyValue(String aLine) throws ParseException {@b@ String line = clean(aLine);@b@ if (line == null) {@b@ return null;@b@ }@b@ String[] split = line.split(" ", 2);@b@ if (split.length != 2) {@b@ //fallback to checking for an equals sign@b@ split = line.split("=", 2);@b@ if (split.length != 2) {@b@ String msg = "Unable to determine Key/Value pair from line [" + line + "]. There is no space from " +@b@ "which the split location could be determined.";@b@ throw new ParseException(msg, 0);@b@ }@b@@b@ }@b@@b@ split[0] = clean(split[0]);@b@ split[1] = clean(split[1]);@b@ if (split[1].startsWith("=")) {@b@ //they used spaces followed by an equals followed by zero or more spaces to split the key/value pair, so@b@ //remove the equals sign to result in only the key and values in the@b@ split[1] = clean(split[1].substring(1));@b@ }@b@@b@ if (split[0] == null) {@b@ String msg = "No valid key could be found in line [" + line + "] to form a key/value pair.";@b@ throw new ParseException(msg, 0);@b@ }@b@ if (split[1] == null) {@b@ String msg = "No corresponding value could be found in line [" + line + "] for key [" + split[0] + "]";@b@ throw new ParseException(msg, 0);@b@ }@b@@b@ return split;@b@ }@b@@b@ public static String[] split(String line) {@b@ return split(line, DEFAULT_DELIMITER_CHAR);@b@ }@b@@b@ public static String[] split(String line, char delimiter) {@b@ return split(line, delimiter, DEFAULT_QUOTE_CHAR);@b@ }@b@@b@ public static String[] split(String line, char delimiter, char quoteChar) {@b@ return split(line, delimiter, quoteChar, quoteChar);@b@ }@b@@b@ public static String[] split(String line, char delimiter, char beginQuoteChar, char endQuoteChar) {@b@ return split(line, delimiter, beginQuoteChar, endQuoteChar, false, true);@b@ }@b@@b@ /**@b@ * Splits the specified delimited String into tokens, supporting quoted tokens so that quoted strings themselves@b@ * won't be tokenized.@b@ * <p/>@b@ * This method's implementation is very loosely based (with significant modifications) on@b@ * <a href="http://blogs.bytecode.com.au/glen">Glen Smith</a>'s open-source@b@ * <a href="http://opencsv.svn.sourceforge.net/viewvc/opencsv/trunk/src/au/com/bytecode/opencsv/CSVReader.java?&view=markup">CSVReader.java</a>@b@ * file.@b@ * <p/>@b@ * That file is Apache 2.0 licensed as well, making Glen's code a great starting point for us to modify to@b@ * our needs.@b@ *@b@ * @param aLine the String to parse@b@ * @param delimiter the delimiter by which the <tt>line</tt> argument is to be split@b@ * @param beginQuoteChar the character signifying the start of quoted text (so the quoted text will not be split)@b@ * @param endQuoteChar the character signifying the end of quoted text@b@ * @param retainQuotes if the quotes themselves should be retained when constructing the corresponding token@b@ * @param trimTokens if leading and trailing whitespace should be trimmed from discovered tokens.@b@ * @return the tokens discovered from parsing the given delimited <tt>line</tt>.@b@ */@b@ public static String[] split(String aLine, char delimiter, char beginQuoteChar, char endQuoteChar,@b@ boolean retainQuotes, boolean trimTokens) {@b@ String line = clean(aLine);@b@ if (line == null) {@b@ return null;@b@ }@b@@b@ List<String> tokens = new ArrayList<String>();@b@ StringBuilder sb = new StringBuilder();@b@ boolean inQuotes = false;@b@@b@ for (int i = 0; i < line.length(); i++) {@b@@b@ char c = line.charAt(i);@b@ if (c == beginQuoteChar) {@b@ // this gets complex... the quote may end a quoted block, or escape another quote.@b@ // do a 1-char lookahead:@b@ if (inQuotes // we are in quotes, therefore there can be escaped quotes in here.@b@ && line.length() > (i + 1) // there is indeed another character to check.@b@ && line.charAt(i + 1) == beginQuoteChar) { // ..and that char. is a quote also.@b@ // we have two quote chars in a row == one quote char, so consume them both and@b@ // put one on the token. we do *not* exit the quoted text.@b@ sb.append(line.charAt(i + 1));@b@ i++;@b@ } else {@b@ inQuotes = !inQuotes;@b@ if (retainQuotes) {@b@ sb.append(c);@b@ }@b@ }@b@ } else if (c == endQuoteChar) {@b@ inQuotes = !inQuotes;@b@ if (retainQuotes) {@b@ sb.append(c);@b@ }@b@ } else if (c == delimiter && !inQuotes) {@b@ String s = sb.toString();@b@ if (trimTokens) {@b@ s = s.trim();@b@ }@b@ tokens.add(s);@b@ sb = new StringBuilder(); // start work on next token@b@ } else {@b@ sb.append(c);@b@ }@b@ }@b@ String s = sb.toString();@b@ if (trimTokens) {@b@ s = s.trim();@b@ }@b@ tokens.add(s);@b@ return tokens.toArray(new String[tokens.size()]);@b@ }@b@@b@ /**@b@ * Joins the elements of the provided {@code Iterator} into@b@ * a single String containing the provided elements.</p>@b@ * <p/>@b@ * No delimiter is added before or after the list.@b@ * A {@code null} separator is the same as an empty String ("").</p>@b@ * <p/>@b@ * Copied from Commons Lang, version 3 (r1138702).</p>@b@ *@b@ * @param iterator the {@code Iterator} of values to join together, may be null@b@ * @param separator the separator character to use, null treated as ""@b@ * @return the joined String, {@code null} if null iterator input@b@ * @since 1.2@b@ */@b@ public static String join(Iterator<?> iterator, String separator) {@b@ final String empty = "";@b@@b@ // handle null, zero and one elements before building a buffer@b@ if (iterator == null) {@b@ return null;@b@ }@b@ if (!iterator.hasNext()) {@b@ return empty;@b@ }@b@ Object first = iterator.next();@b@ if (!iterator.hasNext()) {@b@ return first == null ? empty : first.toString();@b@ }@b@@b@ // two or more elements@b@ StringBuilder buf = new StringBuilder(256); // Java default is 16, probably too small@b@ if (first != null) {@b@ buf.append(first);@b@ }@b@@b@ while (iterator.hasNext()) {@b@ if (separator != null) {@b@ buf.append(separator);@b@ }@b@ Object obj = iterator.next();@b@ if (obj != null) {@b@ buf.append(obj);@b@ }@b@ }@b@ return buf.toString();@b@ }@b@@b@ /**@b@ * Splits the {@code delimited} string (delimited by the specified {@code separator} character) and returns the@b@ * delimited values as a {@code Set}.@b@ * <p/>@b@ * If either argument is {@code null}, this method returns {@code null}.@b@ *@b@ * @param delimited the string to split@b@ * @param separator the character that delineates inpidual tokens to split@b@ * @return the delimited values as a {@code Set}.@b@ * @since 1.2@b@ */@b@ public static Set<String> splitToSet(String delimited, String separator) {@b@ if (delimited == null || separator == null) {@b@ return null;@b@ }@b@ String[] split = split(delimited, separator.charAt(0));@b@ return asSet(split);@b@ }@b@@b@ /**@b@ * Returns the input argument, but ensures the first character is capitalized (if possible).@b@ * @param in the string to uppercase the first character.@b@ * @return the input argument, but with the first character capitalized (if possible).@b@ * @since 1.2@b@ */@b@ public static String uppercaseFirstChar(String in) {@b@ if (in == null || in.length() == 0) {@b@ return in;@b@ }@b@ int length = in.length();@b@ StringBuilder sb = new StringBuilder(length);@b@@b@ sb.append(Character.toUpperCase(in.charAt(0)));@b@ if (length > 1) {@b@ String remaining = in.substring(1);@b@ sb.append(remaining);@b@ }@b@ return sb.toString();@b@ }@b@@b@ //////////////////////////@b@ // From CollectionUtils //@b@ //////////////////////////@b@ // CollectionUtils cannot be removed from shiro-core until 2.0 as it has a dependency on PrincipalCollection@b@@b@@b@ private static <E> Set<E> asSet(E... elements) {@b@ if (elements == null || elements.length == 0) {@b@ return Collections.emptySet();@b@ }@b@@b@ if (elements.length == 1) {@b@ return Collections.singleton(elements[0]);@b@ }@b@@b@ LinkedHashSet<E> set = new LinkedHashSet<E>(elements.length * 4 / 3 + 1);@b@ Collections.addAll(set, elements);@b@ return set;@b@ }@b@@b@}