Maven依賴：
<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.10</version>
</dependency>
API
-
IsEmpty/IsBlank - checks if a String contains text
檢查字符串是否有內容
blank:
空白的；（文件等的）空白處，空格；
empty:
空的；空的東西String s = "This is a test statement"; String blank = " "; String empty = ""; System.out.println(StringUtils.isBlank(s)); //false System.out.println(StringUtils.isBlank(blank)); //true System.out.println(StringUtils.isBlank(empty)); //true System.out.println(StringUtils.isNotBlank(s)); //true System.out.println(StringUtils.isNotBlank(blank)); //false System.out.println(StringUtils.isNotBlank(empty)); //false System.out.println(StringUtils.isEmpty(s)); //flase System.out.println(StringUtils.isEmpty(blank)); //false System.out.println(StringUtils.isEmpty(empty)); //true System.out.println(StringUtils.isNotEmpty(s)); //true System.out.println(StringUtils.isNotEmpty(blank)); //true System.out.println(StringUtils.isNotEmpty(empty)); //false -
Trim/Strip - removes leading and trailing whitespace
刪除字符串開頭和結尾的空白符。
trim:
修剪；除去（不必要部分）
strip:
剝去（外皮）；從（某處）拿走所有東西String s = " This is a test statement "; String empty = ""; System.out.println(s.length());//28 System.out.println(StringUtils.trim(s)+"-"+s.length());//This is a test statement-28 System.out.println(StringUtils.strip(s)+"-"+s.length());//This is a test statement-28 System.out.println(StringUtils.stripToEmpty(empty)); // System.out.println(StringUtils.stripToNull(null)); //null System.out.println(StringUtils.trimToEmpty(empty)); // System.out.println(StringUtils.trimToNull(null)); //null -
Equals/Compare - compares two strings null-safe
比較兩個字符串null安全。
quals()返回boolean compare()返回相差的字符數String s = "This is a test statement"; String s1 = "This is a test statement"; String empty = ""; String n = null; System.out.println(StringUtils.equals(s,s1)); //true System.out.println(StringUtils.compare(s,s1)); //0 System.out.println(StringUtils.equals(s,empty)); //false System.out.println(StringUtils.compare(s,empty)); //24 System.out.println(StringUtils.equals(s,n)); //false System.out.println(StringUtils.compare(s,n)); //1 System.out.println(StringUtils.equals(empty,n)); //false System.out.println(StringUtils.compare(empty,n)); //1 -
startsWith - check if a String starts with a prefix null-safe
檢查字符串是否以xx前綴開始 空安全String s = "This is a test statement"; System.out.println(StringUtils.startsWith(s,"t")); //false -
endsWith - check if a String ends with a suffix null-safe
檢查字符串是否以xx後綴開始 空安全String s = "This is a test statement"; System.out.println(StringUtils.endsWith(s,"t")); //true -
IndexOf/LastIndexOf/Contains - null-safe index-of checks
null安全的索引檢查。String s = "This is a test statement"; System.out.println(StringUtils.indexOf(s,"i")); //2 System.out.println(StringUtils.lastIndexOf(s,"i")); //5 System.out.println(StringUtils.contains(s,"i")); //true -
IndexOfAny/LastIndexOfAny/IndexOfAnyBut - index-of any of a set of Strings
字符串集合索引檢查。
返回數組中的元素最早出現的下標。String s = "This is a test statement"; System.out.println(StringUtils.indexOfAny(s,"e","i")); //2 System.out.println(StringUtils.lastIndexOfAny(s,"i","e")); //21 System.out.println(StringUtils.indexOfAnyBut(s,"T")); //1 -
ContainsOnly/ContainsNone/ContainsAny - does String contains only/none/any of these characters
字符在字符串中出現一次或一次也沒有出現。String s = "This is a test statement"; System.out.println(StringUtils.containsOnly(s,"is")); //false System.out.println(StringUtils.containsNone(s,"hello")); //fasle System.out.println(StringUtils.containsAny(s,"men")); //true -
Substring/Left/Right/Mid - null-safe substring extractions
null安全 子串的提取。String s = "Thisisateststatement"; System.out.println(StringUtils.substring(s,1,6));//[1,6) hisis System.out.println(StringUtils.left(s,3)); //Thi System.out.println(StringUtils.right(s,3)); //ent System.out.println(StringUtils.mid(s,6,3)); //ate -
SubstringBefore/SubstringAfter/SubstringBetween - substring extraction relative to other strings
子串提取依賴其它字符串。String s = "Thisisateststatement"; System.out.println(StringUtils.substringBefore(s,"is")); //Th System.out.println(StringUtils.substringAfter(s,"is")); //isateststatement System.out.println(StringUtils.substringBetween(s,"te")); //ststa -
Split/Join - splits a String into an array of substrings and vice versa
將字符串分割成子字符串數組，反之亦然String s = "This is a"; String s1 = ""; String [] str = new String[]{"1","2","3"}; String[] split = StringUtils.split(s, " "); for (int i = 0; i < split.length; i++) { System.out.println(split[i]);//This is a } System.out.println(s1); System.out.println(StringUtils.join(str,"-"));//1-2-3 -
Remove - removes part of a String
刪除字符串的一部分String s = "This is a"; System.out.println(StringUtils.remove(s,"is"));//Th a System.out.println(s);//This is a -
Replace/Overlay - Searches a String and replaces one String with another
替換字符串的部分字符。String s = "This is a"; System.out.println(StringUtils.replace(s,"is","qaz"));//Thqaz qaz a a System.out.println(s);//This is a System.out.println(StringUtils.overlay(s,"is",0,4));//[0,4) is is a System.out.println(s);//This is a -
Chop - removes the last part of a String
刪除字符串最後的字符。String s = "This isa"; System.out.println(StringUtils.chop(s));//This is System.out.println(s); //This isa -
AppendIfMissing - appends a suffix to the end of the String if not present
在字符串末尾追加後綴(如果不存在)String s = "This isa"; System.out.println(StringUtils.appendIfMissing(s,"a"));//This isa System.out.println(s); //This isa System.out.println(StringUtils.appendIfMissing(s,"s"));//This isas System.out.println(s); //This isa -
PrependIfMissing - prepends a prefix to the start of the String if not present
在字符串開頭(如果不存在)前加上一個前綴String s = "This isa"; System.out.println(StringUtils.prependIfMissing(s,"T"));//This isa System.out.println(s); //This isa System.out.println(StringUtils.prependIfMissing(s,"s"));//sThis isa System.out.println(s); //This isa -
LeftPad/RightPad/Center/Repeat - pads a String
填補一個字符串String s = "101"; System.out.println(StringUtils.leftPad(s,8,"0"));//00000101 System.out.println(StringUtils.rightPad(s,8,"0"));//10100000 System.out.println(StringUtils.center(s,8,"@@@"));//@@101@@@ System.out.println(StringUtils.repeat(s,"---",3));//101---101---101 -
UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize - changes the case of a String
改變字符串的大小寫String s = "daW sWSV VfeFRE"; System.out.println(StringUtils.upperCase(s));//DAW SWSV VFEFRE System.out.println(StringUtils.lowerCase(s));//daw swsv vfefre System.out.println(StringUtils.swapCase(s));//DAw Swsv vFEfre System.out.println(StringUtils.capitalize(s));//首字母大寫 DaW sWSV VfeFRE System.out.println(StringUtils.uncapitalize(s));//取消首字母大寫 daW sWSV VfeFRE -
CountMatches - counts the number of occurrences of one String in another
計算一個字符串在另一個字符串中的出現次數String s = "this is a test statement"; System.out.println(StringUtils.countMatches(s,"s"));//4 -
IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable - checks the characters in a String
檢查字符串中的字符String s = "asds哈哈"; String s1 = " 2134"; String s2 = " "; String s3 = "\u007F"; //檢查字符串是否只包含Unicode字母(所有漢字+英文字母，數字和符號大多不包括在內) System.out.println(StringUtils.isAlpha(s));//true //檢查字符串是否只包含Unicode數字 System.out.println(StringUtils.isNumeric(s1));//false //檢查字符串是否只包含空格 System.out.println(StringUtils.isWhitespace(s2));//true //檢查字符串是否只包含ASCII可打印字符(95個可打印字符（0x20-0x7E）) System.out.println(StringUtils.isAsciiPrintable(s3));//false -
DefaultString - protects against a null input String
防止null輸入字符串String s =null; System.out.println(StringUtils.defaultString(s,"default"));//default -
Rotate - rotate (circular shift) a String
旋轉(循環移位)字符串String s ="abcdefg"; System.out.println(StringUtils.rotate(s,0));//abcdefg System.out.println(StringUtils.rotate(s,2));//fgabcde System.out.println(StringUtils.rotate(s,-2));//cdefgab System.out.println(StringUtils.rotate(s,7));//abcdefg System.out.println(StringUtils.rotate(s,-7));//abcdefg System.out.println(StringUtils.rotate(s,9));//fgabcde System.out.println(StringUtils.rotate(s,-9));//cdefgab -
Reverse/ReverseDelimited - reverses a String
反轉字符串String s ="abcdefg"; System.out.println(StringUtils.reverse(s));//gfedcba System.out.println(StringUtils.reverseDelimited(s,'d'));//efgdabc -
Abbreviate - abbreviates a string using ellipsis or another given String
使用省略號或其他給定字符串縮寫字符串
String s ="據香港特區政府新聞網站消息";
System.out.println(StringUtils.abbreviate(s,"...",8));//據香港特區...
- Difference - compares Strings and reports on their differences
比較字符串和報告的差異
String s = "ab";
System.out.println(StringUtils.difference(s,"abxyz"));//xyz