Spring的StringUtils工具类

StringUtils.hasLength(null) = false;   StringUtils.hasLength("") = false;   StringUtils.hasLength(" ") = true;   StringUtils.hasLength("Hello") = true;      StringUtils.hasText(null) = false;   StringUtils.hasText("") = false;   StringUtils.hasText(" ") = false;   StringUtils.hasText("12345") = true;   StringUtils.hasText(" 12345 ") = true;     //是否包含空白字符   StringUtils.containsWhitespace(null)=false;   StringUtils.containsWhitespace("")=false;   StringUtils.containsWhitespace("a")=false;   StringUtils.containsWhitespace("abc")=false;   StringUtils.containsWhitespace("abc")=false;   StringUtils.containsWhitespace(" ")=true;   StringUtils.containsWhitespace(" a")=true;   StringUtils.containsWhitespace("abc ")=true;   StringUtils.containsWhitespace("a b")=true   StringUtils.containsWhitespace("a  b")     StringUtils.trimWhitespace(null)=null;   StringUtils.trimWhitespace("")="";   StringUtils.trimWhitespace(" ")="";   StringUtils.trimWhitespace("/t")="";   StringUtils.trimWhitespace(" a")="a";   StringUtils.trimWhitespace("a ")="a";   StringUtils.trimWhitespace(" a ")="a";   StringUtils.trimWhitespace(" a b ")="a b";     StringUtils.trimLeadingWhitespace(null)=null;   StringUtils.trimLeadingWhitespace("")="";   StringUtils.trimLeadingWhitespace(" ")="";   StringUtils.trimLeadingWhitespace("/t")="";   StringUtils.trimLeadingWhitespace(" a")="a";   StringUtils.trimLeadingWhitespace("a ")="a ";   StringUtils.trimLeadingWhitespace(" a ")="a ";   StringUtils.trimLeadingWhitespace(" a b ")="a b "   StringUtils.trimLeadingWhitespace(" a b  c ")="a b  c "     StringUtils.trimTrailingWhitespace(null)=null;   StringUtils.trimTrailingWhitespace(" ")="";   StringUtils.trimTrailingWhitespace("/t")="";   StringUtils.trimTrailingWhitespace("a ")="a";   StringUtils.trimTrailingWhitespace(" a")=" a";   StringUtils.trimTrailingWhitespace(" a ")=" a";   StringUtils.trimTrailingWhitespace(" a b ")=" a b";   StringUtils.trimTrailingWhitespace(" a b  c ")=" a b  c";       StringUtils.trimAllWhitespace("")="";   StringUtils.trimAllWhitespace(" ")="";   StringUtils.trimAllWhitespace("/t")="";   StringUtils.trimAllWhitespace(" a")="a";   StringUtils.trimAllWhitespace("a ")="a";   StringUtils.trimAllWhitespace(" a ")="a";   StringUtils.trimAllWhitespace(" a b ")="ab";   StringUtils.trimAllWhitespace(" a b  c "="abc";   // 统计一个子字符串在字符串出现的次数   StringUtils.countOccurrencesOf(null, null) == 0;   StringUtils.countOccurrencesOf("s", null) == 0;   StringUtils.countOccurrencesOf(null, "s") == 0;   StringUtils.countOccurrencesOf("erowoiueoiur", "WERWER") == 0;   StringUtils.countOccurrencesOf("erowoiueoiur", "x")=0;   StringUtils.countOccurrencesOf("erowoiueoiur", " ") == 0;   StringUtils.countOccurrencesOf("erowoiueoiur", "") == 0;   StringUtils.countOccurrencesOf("erowoiueoiur", "e") == 2;   StringUtils.countOccurrencesOf("erowoiueoiur", "oi") == 2;   StringUtils.countOccurrencesOf("erowoiueoiur", "oiu") == 2;   StringUtils.countOccurrencesOf("erowoiueoiur", "oiur") == 1;   StringUtils.countOccurrencesOf("erowoiueoiur", "r") == 2;     //字符串替换   String inString = "a6AazAaa77abaa";   String oldPattern = "aa";   String newPattern = "foo";   // Simple replace   String s = StringUtils.replace(inString, oldPattern, newPattern);   s.equals("a6AazAfoo77abfoo")=true;     // Non match: no change   s = StringUtils.replace(inString, "qwoeiruqopwieurpoqwieur", newPattern);   s.equals(inString)=true   s = StringUtils.replace(inString, oldPattern, null);   s.equals(inString)=true     // Null old pattern: should ignore   s = StringUtils.replace(inString, null, newPattern);          s.equals(inString)=true     //删除字符串   String inString = "The quick brown fox jumped over the lazy dog";   String noThe = StringUtils.delete(inString, "the");   noThe.equals("The quick brown fox jumped over  lazy dog")=true;   String nohe = StringUtils.delete(inString, "he");   nohe.equals("T quick brown fox jumped over t lazy dog")=true;   String nosp = StringUtils.delete(inString, " ");   nosp.equals("Thequickbrownfoxjumpedoverthelazydog")=true;   String killEnd = StringUtils.delete(inString, "dog");   killEnd.equals("The quick brown fox jumped over the lazy ")=true;   String mismatch = StringUtils.delete(inString, "dxxcxcxog");    mismatch.equals(inString)=true;     //删除任何字符   //源代码如下   //char c = inString.charAt(i);   //如果不存在 c 值，则返回 -1   //if (charsToDelete.indexOf(c) == -1) {   //out.append(c);   //}     String inString = "Able was I ere I saw Elba";     String res = StringUtils.deleteAny(inString, "I");          res.equals("Able was  ere  saw Elba")=true;   res = StringUtils.deleteAny(inString, "AeEba!");   res.equals("l ws I r I sw l")=true;   String mismatch = StringUtils.deleteAny(inString, "#@$#$^");   mismatch.equals(inString)=true;     //源代码如下 return (str != null ? "'" + str + "'" : null);   assertEquals("'myString'", StringUtils.quote("myString"));   assertEquals("''", StringUtils.quote(""));   assertNull(StringUtils.quote(null));   //将第一个字符改大写   StringUtils.capitalize(Str)   //将第一个个字符改小写   StringUtils.uncapitalize(str)     //mypath/myfile.txt" -> "myfile.txt   //获取字符串文件名和扩展名   StringUtils.getFilename("myfile").equals("myfile")=true;   StringUtils.getFilename("mypath/myfile".equals("myfile")=true;   StringUtils.getFilename("mypath/myfile".equals("myfile")=true;   StringUtils.getFilename("myfile.txt").equals("myfile.txt")=true;   StringUtils.getFilename("mypath/myfile.txt").equals("myfile.txt")=true;     // 获取字符串扩展名,以.分隔   StringUtils.getFilenameExtension("myfile")=null;   StringUtils.getFilenameExtension("myPath/myfile")=null;   StringUtils.getFilenameExtension("myfile.").equals("")=true;   StringUtils.getFilenameExtension("myPath/myfile.").equals("")=true;   StringUtils.StringUtils.getFilenameExtension("myfile.txt").equals("txt")=true;   StringUtils.getFilenameExtension("mypath/myfile.txt").equals("txt")=true;     //舍去文件名扩展名   StringUtils.stripFilenameExtension(null)=true;   StringUtils.stripFilenameExtension("").equals("")=true;   StringUtils.stripFilenameExtension("myfile").equals("myfile")=true;   StringUtils.stripFilenameExtension("mypath/myfile").equals("mypath/myfile")=true;   StringUtils.stripFilenameExtension("myfile.").equals("myfile")=true;   StringUtils.stripFilenameExtension("mypath/myfile.").equals("mypath/myfile")=true;   StringUtils.stripFilenameExtension("mypath/myfile.").equals("mypath/myfile")=true;   StringUtils.stripFilenameExtension("myfile.txt").equals("myfile")=true;   StringUtils.stripFilenameExtension("mypath/myfile.txt").equals("mypath/myfile")=true