[Commons lang3 topic] 001 stringutils topic

【commons-lang3 project 】001-StringUtils project

〇、 Get ready

1、StringUtils The main role

Provide all kinds of String manipulation Method .

2、 Introduce dependencies

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.12.0</version>
</dependency>

One 、 Judgment is not empty

1、 Determines if the string is empty ：null、“”、" " by true , For the other false

// 1、 Determines if the string is empty ：null、""、" "  by  true , For the other  false
System.out.println(StringUtils.isBlank(null)); // true
System.out.println(StringUtils.isBlank("")); // true
System.out.println(StringUtils.isBlank(" ")); // true
System.out.println(StringUtils.isBlank(" zibo ")); // false

2、 Determine if the string is not empty （ And isBlank contrary ）：null、“”、" " by false , For the other true

// 2、 Determine if the string is not empty （ And  isBlank  contrary ）：null、""、" "  by  false , For the other  true
System.out.println(StringUtils.isNotBlank(null)); // true
System.out.println(StringUtils.isNotBlank("")); // true
System.out.println(StringUtils.isNotBlank(" ")); // true
System.out.println(StringUtils.isNotBlank(" zibo ")); // true

3、 Determines if the string is empty ：null、“” by true , For the other false

// 3、 Determines if the string is empty ：null、""  by  true , For the other  false
System.out.println(StringUtils.isEmpty(null)); // true
System.out.println(StringUtils.isEmpty("")); // true
System.out.println(StringUtils.isEmpty(" ")); // false
System.out.println(StringUtils.isEmpty(" zibo ")); // false

4、 Determine if the string is not empty （ And isEmpty contrary ）：null、“” by false , For the other true

// 4、 Determine if the string is not empty （ And  isEmpty  contrary ）：null、""  by  false , For the other  true
System.out.println(StringUtils.isNotEmpty(null)); // false
System.out.println(StringUtils.isNotEmpty("")); // false
System.out.println(StringUtils.isNotEmpty(" ")); // true
System.out.println(StringUtils.isNotEmpty(" zibo ")); // true

Two 、 Judgment type

5、 Determine whether the string is a number , Don't ignore spaces

// 5、 Determine whether the string is a number , Don't ignore spaces 
System.out.println(StringUtils.isNumeric("")); // false
System.out.println(StringUtils.isNumeric(" ")); // false
System.out.println(StringUtils.isNumeric("100")); // true
System.out.println(StringUtils.isNumeric(" 100 ")); // false
//  Note that the following even decimals also return  `false` , This is something I didn't expect ！
System.out.println(StringUtils.isNumeric("100.0")); // false

6、 Determine whether the string is a number , Ignore spaces

// 6、 Determine whether the string is a number , Ignore spaces 
//  Empty string returns  `true` , I was stunned ！
System.out.println(StringUtils.isNumericSpace("")); // true
//  Space string return  `true` , I was stunned ！
System.out.println(StringUtils.isNumericSpace(" ")); // true
System.out.println(StringUtils.isNumericSpace("100")); // true
System.out.println(StringUtils.isNumericSpace(" 100 ")); // true
//  Note that the following even decimals also return  `false` , This is something I didn't expect ！
System.out.println(StringUtils.isNumericSpace("100.0")); // false

7、 Determine whether the string is a Greek letter , Don't ignore spaces

// 7、 Determine whether the string is a Greek letter , Don't ignore spaces 
//  The Greek letter ？ I'm afraid I won't use this function for 10000 years ！
System.out.println(StringUtils.isAlpha("")); // false
System.out.println(StringUtils.isAlpha(" ")); // false
System.out.println(StringUtils.isAlpha("zibo")); // true
System.out.println(StringUtils.isAlpha(" zibo ")); // false
System.out.println(StringUtils.isAlpha("zibo zibo")); // false
System.out.println(StringUtils.isAlpha("zibo123")); // false

8、 Determine whether the string is a Greek letter , Ignore spaces

// 8、 Determine whether the string is a Greek letter , Ignore spaces 
//  It is also an empty string , Ignore spaces and return  `true` , I was stunned ！ Is there a difference ！
System.out.println(StringUtils.isAlphaSpace("")); // true
System.out.println(StringUtils.isAlphaSpace(" ")); // true
System.out.println(StringUtils.isAlphaSpace("zibo")); // true
System.out.println(StringUtils.isAlphaSpace(" zibo ")); // true
System.out.println(StringUtils.isAlphaSpace("zibo zibo")); // true
System.out.println(StringUtils.isAlphaSpace("zibo123")); // false

9、 Judge whether the string is composed of Greek letters and numbers , Don't ignore spaces

// 9、 Judge whether the string is composed of Greek letters and numbers , Don't ignore spaces 
//  It's another function that won't be used in 10000 years ！
System.out.println(StringUtils.isAlphanumeric("")); // false
System.out.println(StringUtils.isAlphanumeric(" ")); // false
//  thus it can be seen , This is an inclusive relationship ！ Letters and numbers are not required , One of them also returns  `true` ！
System.out.println(StringUtils.isAlphanumeric("zibo")); // true
System.out.println(StringUtils.isAlphanumeric("123")); // true
System.out.println(StringUtils.isAlphanumeric("zibo123")); // true
System.out.println(StringUtils.isAlphanumeric("zibo123 ")); // false

10、 Judge whether the string is composed of Greek letters and numbers , Ignore spaces

// 10、 Judge whether the string is composed of Greek letters and numbers , Ignore spaces 
//  It is also an empty string , Ignore spaces and return  `true` , I was stunned ！ Is there a difference ！
System.out.println(StringUtils.isAlphanumericSpace("")); // true
System.out.println(StringUtils.isAlphanumericSpace(" ")); // true
System.out.println(StringUtils.isAlphanumericSpace("zibo")); // true
System.out.println(StringUtils.isAlphanumericSpace("123")); // true
System.out.println(StringUtils.isAlphanumericSpace("zibo123")); // true
System.out.println(StringUtils.isAlphanumericSpace("zibo123 ")); // true

3、 ... and 、 Determine case

11、 Determine whether the string is all lowercase

// 11、 Determine whether the string is all lowercase 
System.out.println(StringUtils.isAllLowerCase("zibo")); // true
System.out.println(StringUtils.isAllLowerCase("ZiBo")); // false
System.out.println(StringUtils.isAllLowerCase("ZIBO")); // false

12、 Determine whether the string is all capital letters

// 12、 Determine whether the string is all capital letters 
System.out.println(StringUtils.isAllUpperCase("ZIBO")); // true
System.out.println(StringUtils.isAllUpperCase("ZiBo")); // false
System.out.println(StringUtils.isAllUpperCase("zibo")); // false

Four 、 Judgment includes

13、 Judge whether the source string contains the target string

// 13、 Judge whether the source string contains the target string 
System.out.println(StringUtils.contains("zibo", "zibo")); // true
//  so , Case sensitive ！
System.out.println(StringUtils.contains("zibo", "ZIBO")); // false
System.out.println(StringUtils.contains("zibo", "")); // true
//  Don't ignore spaces , return  `false` ！
System.out.println(StringUtils.contains("zibo", " ")); // false

14、 Determine whether the source string contains the destination byte

// 14、 Determine whether the source string contains the destination byte 
System.out.println(StringUtils.contains("zibo", 'z')); // true
//  so , Case sensitive ！
System.out.println(StringUtils.contains("zibo", 'Z')); // false
System.out.println(StringUtils.contains("zibo", 'a')); // false

15、 Judge whether the source string contains the target string （ Multiple goals ）

// 15、 Judge whether the source string contains the target string （ Multiple goals ）
System.out.println(StringUtils.containsAny("zibo", "zibo")); // true
//  Multiple target strings 
System.out.println(StringUtils.containsAny("zibo", "zi", "bo")); // true
//  so , Case sensitive ！
System.out.println(StringUtils.containsAny("zibo", "ZIBO")); // false

16、 Determine whether the source string contains the destination byte （ Multiple goals ）

// 16、 Determine whether the source string contains the destination byte （ Multiple goals ）
//  Multiple target strings 
System.out.println(StringUtils.containsAny("zibo", 'z')); // true
System.out.println(StringUtils.containsAny("zibo", 'z', 'b')); // true
//  unexpected ： There is a , Also returned  `true` ！
System.out.println(StringUtils.containsAny("zibo", 'z', 'a')); // true
System.out.println(StringUtils.containsAny("zibo", 'a')); // false

5、 ... and 、 Space before and after

17、 Remove the space before and after the string (““ return ””)

// 17、 Remove the space before and after the string ("" return "")
//  If it is null, it returns null , by  null  When to return to  null( It's not a string null, Prevent null pointer exception )
System.out.println(StringUtils.trim(null)); // null
System.out.println(StringUtils.trim(" zibo ")); // zibo
System.out.println(StringUtils.trim(" ")); // ""

18、 Remove the space before and after the string ("" return null )

// 18、 Remove the space before and after the string ("" return  `null` )
//  When empty , return  null( It's not a string null, Prevent null pointer exception )
System.out.println(StringUtils.trimToNull(null)); // null
System.out.println(StringUtils.trimToNull(" zibo ")); // zibo
System.out.println(StringUtils.trimToNull(" ")); // null

19、 Remove the space before and after the string (null return "" )

// 19、 Remove the space before and after the string (null return "" )
System.out.println(StringUtils.trimToEmpty(null)); // ""
System.out.println(StringUtils.trimToEmpty(" zibo ")); // zibo
System.out.println(StringUtils.trimToEmpty(" ")); // ""

6、 ... and 、 Determine whether two strings are equal

20、 Compare two strings for equality （ Case sensitive ）

// 20、 Compare two strings for equality （ Case sensitive ）
System.out.println(StringUtils.equals("zibo", "zibo")); // true
System.out.println(StringUtils.equals("zibo", "ZIBO")); // false

21、 Compare two strings for equality （ Ignore case ）

// 21、 Compare two strings for equality （ Ignore case ）
System.out.println(StringUtils.equalsIgnoreCase("zibo", "zibo")); // true
System.out.println(StringUtils.equalsIgnoreCase("zibo", "ZIBO")); // true

7、 ... and 、 Find the target string location

22、 Find the position where the target string first appears in the source string , No return -1

// 22、 Find the position where the target string first appears in the source string , No return -1
System.out.println(StringUtils.indexOf("zibo", "z")); // 0
System.out.println(StringUtils.indexOf("zibo", "a")); // -1

23、 Find the position where the target string first appears in the source string , No return -1（ Start at the specified location ）

// 23、 Find the position where the target string first appears in the source string , No return -1（ Start at the specified location ）
System.out.println(StringUtils.indexOf("zibo", "i", 0)); // 1
System.out.println(StringUtils.indexOf("zibo", "i", 1)); // 1
System.out.println(StringUtils.indexOf("zibo", "i", 2)); // -1

24、 Find the index position of any element in the array in the source string , Meet multiple hours , Minimum value , No return -1（ Multiple goals ）

// 24、 Find the index position of any element in the array in the source string , Meet multiple hours , Minimum value , No return -1（ Multiple goals ）
System.out.println(StringUtils.indexOfAny("zibo", "z", "i")); // 0
System.out.println(StringUtils.indexOfAny("zibo", "b", "o")); // 2
System.out.println(StringUtils.indexOfAny("zibo", "b", "t")); // 2

8、 ... and 、 toggle case

25、 String letter to lowercase

// 25、 String letter to lowercase 
System.out.println(StringUtils.lowerCase("ZIBO")); // zibo

26、 String letters to uppercase

// 26、 String letters to uppercase 
System.out.println(StringUtils.upperCase("zibo")); // ZIBO

27、 Capitalize the initial

// 28、 Capitalize the initial 
System.out.println(StringUtils.capitalize("zibo")); // Zibo

Nine 、 Omission and supplement

28、 Yes str The string is abbreviated by ellipsis

// 27、 Yes  str  The string is abbreviated by ellipsis 
// maxWidth  Length , Must be greater than or equal to 4（ Indicates the length after abbreviation ）
System.out.println(StringUtils.abbreviate("zibo zibo zibo", 4)); // z...

29、 take str Fill in blanks before and after , Bring the total length to size

// 29、 take  str  Fill in blanks before and after , Bring the total length to  size
// size  Itself is less than  str  Length , No filling 
System.out.println(StringUtils.center("zibo", 6)); // " zibo "

30、 Fill with the specified string

// 30、 Fill with the specified string 
System.out.println(StringUtils.center("zibo", 6, "*")); // "*zibo*"

Ten 、 Compare strings

31、 Compare strings str1 And str2 Size （ Case sensitive ）

// 31、 Compare strings  str1  And  str2  Size （ Case sensitive ）
System.out.println(StringUtils.compare("a", "a")); // 0
System.out.println(StringUtils.compare("a", "b")); // -1
System.out.println(StringUtils.compare("b", "a")); // 1
System.out.println(StringUtils.compare("a", "A")); // 32

32、 Compare strings str1 And str2 Size （ Ignore case ）

// 32、 Compare strings  str1  And  str2  Size （ Ignore case ）
System.out.println(StringUtils.compareIgnoreCase("a", "A")); // 0
System.out.println(StringUtils.compareIgnoreCase("a", null, true)); // 1
System.out.println(StringUtils.compareIgnoreCase(null, null, true)); // 0
System.out.println(StringUtils.compareIgnoreCase("a", null, false)); // -1
System.out.println(StringUtils.compareIgnoreCase(null, null, false)); // 0
System.out.println(StringUtils.compareIgnoreCase("z", null, true)); // 1
System.out.println(StringUtils.compareIgnoreCase("z", null, false)); // -1

11、 ... and 、 Find the number of occurrences

33、 Find a target character / The number of times the string appears in the source string

// 33、 Find a target character / The number of times the string appears in the source string 
System.out.println(StringUtils.countMatches("zibo zibo zibo", "z")); // 3

Twelve 、 The separator separates

34、 Connect the array with the specified separator

// 34、 Connect the array with the specified separator 
// liubei,guanyu,zhangfei
System.out.println(StringUtils.join(new String[]{
    "liubei", "guanyu", "zhangfei"}, ","));
System.out.println(StringUtils.join("a", "b", "c")); // abc
System.out.println(StringUtils.join(Arrays.asList("a", "b", "c"), ",")); // a,b,c
// [a, b, c],[d, e, f]
System.out.println(StringUtils.joinWith(",", Arrays.asList("a", "b", "c"), Arrays.asList("d", "e", "f")));

13、 ... and 、 Null, default value

35、 If the string is null 、“”、 " ", Returns the default string

// 35、 If the string is  null 、""、 " ", Returns the default string 
System.out.println(StringUtils.defaultIfBlank(null, "default")); // default
System.out.println(StringUtils.defaultIfBlank("", "default")); // default
System.out.println(StringUtils.defaultIfBlank(" ", "default")); // default

36、 If the string is null 、“” , Returns the default string

// 36、 If the string is  null 、"" , Returns the default string 
System.out.println(StringUtils.defaultIfEmpty(null, "default")); // default
System.out.println(StringUtils.defaultIfEmpty("", "default")); // default
System.out.println(StringUtils.defaultIfEmpty(" ", "default")); // " "

fourteen 、 Complete code

package com.zibo.zibo2022.string_utils.main;

import java.util.Arrays;
import org.apache.commons.lang3.StringUtils;

public class Main {
    

    public static void main(String[] args) {
    
        // start
        // 1、 Determines if the string is empty ：null、""、" "  by  true , For the other  false
        System.out.println(StringUtils.isBlank(null)); // true
        System.out.println(StringUtils.isBlank("")); // true
        System.out.println(StringUtils.isBlank(" ")); // true
        System.out.println(StringUtils.isBlank(" zibo ")); // false

        // 2、 Determine if the string is not empty （ And  isBlank  contrary ）：null、""、" "  by  false , For the other  true
        System.out.println(StringUtils.isNotBlank(null)); // true
        System.out.println(StringUtils.isNotBlank("")); // true
        System.out.println(StringUtils.isNotBlank(" ")); // true
        System.out.println(StringUtils.isNotBlank(" zibo ")); // true

        // 3、 Determines if the string is empty ：null、""  by  true , For the other  false
        System.out.println(StringUtils.isEmpty(null)); // true
        System.out.println(StringUtils.isEmpty("")); // true
        System.out.println(StringUtils.isEmpty(" ")); // false
        System.out.println(StringUtils.isEmpty(" zibo ")); // false

        // 4、 Determine if the string is not empty （ And  isEmpty  contrary ）：null、""  by  false , For the other  true
        System.out.println(StringUtils.isNotEmpty(null)); // false
        System.out.println(StringUtils.isNotEmpty("")); // false
        System.out.println(StringUtils.isNotEmpty(" ")); // true
        System.out.println(StringUtils.isNotEmpty(" zibo ")); // true

        // 5、 Determine whether the string is a number , Don't ignore spaces 
        System.out.println(StringUtils.isNumeric("")); // false
        System.out.println(StringUtils.isNumeric(" ")); // false
        System.out.println(StringUtils.isNumeric("100")); // true
        System.out.println(StringUtils.isNumeric(" 100 ")); // false
        //  Note that the following even decimals also return  `false` , This is something I didn't expect ！
        System.out.println(StringUtils.isNumeric("100.0")); // false

        // 6、 Determine whether the string is a number , Ignore spaces 
        //  Empty string returns  `true` , I was stunned ！
        System.out.println(StringUtils.isNumericSpace("")); // true
        //  Space string return  `true` , I was stunned ！
        System.out.println(StringUtils.isNumericSpace(" ")); // true
        System.out.println(StringUtils.isNumericSpace("100")); // true
        System.out.println(StringUtils.isNumericSpace(" 100 ")); // true
        //  Note that the following even decimals also return  `false` , This is something I didn't expect ！
        System.out.println(StringUtils.isNumericSpace("100.0")); // false

        // 7、 Determine whether the string is a Greek letter , Don't ignore spaces 
        //  The Greek letter ？ I'm afraid I won't use this function for 10000 years ！
        System.out.println(StringUtils.isAlpha("")); // false
        System.out.println(StringUtils.isAlpha(" ")); // false
        System.out.println(StringUtils.isAlpha("zibo")); // true
        System.out.println(StringUtils.isAlpha(" zibo ")); // false
        System.out.println(StringUtils.isAlpha("zibo zibo")); // false
        System.out.println(StringUtils.isAlpha("zibo123")); // false

        // 8、 Determine whether the string is a Greek letter , Ignore spaces 
        //  It is also an empty string , Ignore spaces and return  `true` , I was stunned ！ Is there a difference ！
        System.out.println(StringUtils.isAlphaSpace("")); // true
        System.out.println(StringUtils.isAlphaSpace(" ")); // true
        System.out.println(StringUtils.isAlphaSpace("zibo")); // true
        System.out.println(StringUtils.isAlphaSpace(" zibo ")); // true
        System.out.println(StringUtils.isAlphaSpace("zibo zibo")); // true
        System.out.println(StringUtils.isAlphaSpace("zibo123")); // false

        // 9、 Judge whether the string is composed of Greek letters and numbers , Don't ignore spaces 
        //  It's another function that won't be used in 10000 years ！
        System.out.println(StringUtils.isAlphanumeric("")); // false
        System.out.println(StringUtils.isAlphanumeric(" ")); // false
        //  thus it can be seen , This is an inclusive relationship ！ Letters and numbers are not required , One of them also returns  `true` ！
        System.out.println(StringUtils.isAlphanumeric("zibo")); // true
        System.out.println(StringUtils.isAlphanumeric("123")); // true
        System.out.println(StringUtils.isAlphanumeric("zibo123")); // true
        System.out.println(StringUtils.isAlphanumeric("zibo123 ")); // false

        // 10、 Judge whether the string is composed of Greek letters and numbers , Ignore spaces 
        //  It is also an empty string , Ignore spaces and return  `true` , I was stunned ！ Is there a difference ！
        System.out.println(StringUtils.isAlphanumericSpace("")); // true
        System.out.println(StringUtils.isAlphanumericSpace(" ")); // true
        System.out.println(StringUtils.isAlphanumericSpace("zibo")); // true
        System.out.println(StringUtils.isAlphanumericSpace("123")); // true
        System.out.println(StringUtils.isAlphanumericSpace("zibo123")); // true
        System.out.println(StringUtils.isAlphanumericSpace("zibo123 ")); // true

        // 11、 Determine whether the string is all lowercase 
        System.out.println(StringUtils.isAllLowerCase("zibo")); // true
        System.out.println(StringUtils.isAllLowerCase("ZiBo")); // false
        System.out.println(StringUtils.isAllLowerCase("ZIBO")); // false

        // 12、 Determine whether the string is all capital letters 
        System.out.println(StringUtils.isAllUpperCase("ZIBO")); // true
        System.out.println(StringUtils.isAllUpperCase("ZiBo")); // false
        System.out.println(StringUtils.isAllUpperCase("zibo")); // false

        // 13、 Judge whether the source string contains the target string 
        System.out.println(StringUtils.contains("zibo", "zibo")); // true
        //  so , Case sensitive ！
        System.out.println(StringUtils.contains("zibo", "ZIBO")); // false
        System.out.println(StringUtils.contains("zibo", "")); // true
        //  Don't ignore spaces , return  `false` ！
        System.out.println(StringUtils.contains("zibo", " ")); // false

        // 14、 Determine whether the source string contains the destination byte 
        System.out.println(StringUtils.contains("zibo", 'z')); // true
        //  so , Case sensitive ！
        System.out.println(StringUtils.contains("zibo", 'Z')); // false
        System.out.println(StringUtils.contains("zibo", 'a')); // false

        // 15、 Judge whether the source string contains the target string （ Multiple goals ）
        System.out.println(StringUtils.containsAny("zibo", "zibo")); // true
        //  Multiple target strings 
        System.out.println(StringUtils.containsAny("zibo", "zi", "bo")); // true
        //  so , Case sensitive ！
        System.out.println(StringUtils.containsAny("zibo", "ZIBO")); // false

        // 16、 Determine whether the source string contains the destination byte （ Multiple goals ）
        //  Multiple target strings 
        System.out.println(StringUtils.containsAny("zibo", 'z')); // true
        System.out.println(StringUtils.containsAny("zibo", 'z', 'b')); // true
        //  unexpected ： There is a , Also returned  `true` ！
        System.out.println(StringUtils.containsAny("zibo", 'z', 'a')); // true
        System.out.println(StringUtils.containsAny("zibo", 'a')); // false

        // 17、 Remove the space before and after the string ("" return "")
        //  If it is null, it returns null , by  null  When to return to  null( It's not a string null, Prevent null pointer exception )
        System.out.println(StringUtils.trim(null)); // null
        System.out.println(StringUtils.trim(" zibo ")); // zibo
        System.out.println(StringUtils.trim(" ")); // ""

        // 18、 Remove the space before and after the string ("" return  `null` )
        //  When empty , return  null( It's not a string null, Prevent null pointer exception )
        System.out.println(StringUtils.trimToNull(null)); // null
        System.out.println(StringUtils.trimToNull(" zibo ")); // zibo
        System.out.println(StringUtils.trimToNull(" ")); // null

        // 19、 Remove the space before and after the string (null return "" )
        System.out.println(StringUtils.trimToEmpty(null)); // ""
        System.out.println(StringUtils.trimToEmpty(" zibo ")); // zibo
        System.out.println(StringUtils.trimToEmpty(" ")); // ""

        // 20、 Compare two strings for equality （ Case sensitive ）
        System.out.println(StringUtils.equals("zibo", "zibo")); // true
        System.out.println(StringUtils.equals("zibo", "ZIBO")); // false

        // 21、 Compare two strings for equality （ Ignore case ）
        System.out.println(StringUtils.equalsIgnoreCase("zibo", "zibo")); // true
        System.out.println(StringUtils.equalsIgnoreCase("zibo", "ZIBO")); // true

        // 22、 Find the position where the target string first appears in the source string , No return -1
        System.out.println(StringUtils.indexOf("zibo", "z")); // 0
        System.out.println(StringUtils.indexOf("zibo", "a")); // -1

        // 23、 Find the position where the target string first appears in the source string , No return -1（ Start at the specified location ）
        System.out.println(StringUtils.indexOf("zibo", "i", 0)); // 1
        System.out.println(StringUtils.indexOf("zibo", "i", 1)); // 1
        System.out.println(StringUtils.indexOf("zibo", "i", 2)); // -1

        // 24、 Find the index position of any element in the array in the source string , Meet multiple hours , Minimum value , No return -1（ Multiple goals ）
        System.out.println(StringUtils.indexOfAny("zibo", "z", "i")); // 0
        System.out.println(StringUtils.indexOfAny("zibo", "b", "o")); // 2
        System.out.println(StringUtils.indexOfAny("zibo", "b", "t")); // 2

        // 25、 String letter to lowercase 
        System.out.println(StringUtils.lowerCase("ZIBO")); // zibo

        // 26、 String letters to uppercase 
        System.out.println(StringUtils.upperCase("zibo")); // ZIBO

        // 27、 Yes  str  The string is abbreviated by ellipsis 
        // maxWidth  Length , Must be greater than or equal to 4（ Indicates the length after abbreviation ）
        System.out.println(StringUtils.abbreviate("zibo zibo zibo", 4)); // z...

        // 28、 Capitalize the initial 
        System.out.println(StringUtils.capitalize("zibo")); // Zibo

        // 29、 take  str  Fill in blanks before and after , Bring the total length to  size
        // size  Itself is less than  str  Length , No filling 
        System.out.println(StringUtils.center("zibo", 6)); // " zibo "

        // 30、 Fill with the specified string 
        System.out.println(StringUtils.center("zibo", 6, "*")); // "*zibo*"

        // 31、 Compare strings  str1  And  str2  Size （ Case sensitive ）
        System.out.println(StringUtils.compare("a", "a")); // 0
        System.out.println(StringUtils.compare("a", "b")); // -1
        System.out.println(StringUtils.compare("b", "a")); // 1
        System.out.println(StringUtils.compare("a", "A")); // 32

        // 32、 Compare strings  str1  And  str2  Size （ Ignore case ）
        System.out.println(StringUtils.compareIgnoreCase("a", "A")); // 0
        System.out.println(StringUtils.compareIgnoreCase("a", null, true)); // 1
        System.out.println(StringUtils.compareIgnoreCase(null, null, true)); // 0
        System.out.println(StringUtils.compareIgnoreCase("a", null, false)); // -1
        System.out.println(StringUtils.compareIgnoreCase(null, null, false)); // 0
        System.out.println(StringUtils.compareIgnoreCase("z", null, true)); // 1
        System.out.println(StringUtils.compareIgnoreCase("z", null, false)); // -1

        // 33、 Find a target character / The number of times the string appears in the source string 
        System.out.println(StringUtils.countMatches("zibo zibo zibo", "z")); // 3

        // 34、 Connect the array with the specified separator 
        // liubei,guanyu,zhangfei
        System.out.println(StringUtils.join(new String[]{
    "liubei", "guanyu", "zhangfei"}, ","));
        System.out.println(StringUtils.join("a", "b", "c")); // abc
        System.out.println(StringUtils.join(Arrays.asList("a", "b", "c"), ",")); // a,b,c
        // [a, b, c],[d, e, f]
        System.out.println(StringUtils.joinWith(",", Arrays.asList("a", "b", "c"), Arrays.asList("d", "e", "f")));

        // 35、 If the string is  null 、""、 " ", Returns the default string 
        System.out.println(StringUtils.defaultIfBlank(null, "default")); // default
        System.out.println(StringUtils.defaultIfBlank("", "default")); // default
        System.out.println(StringUtils.defaultIfBlank(" ", "default")); // default

        // 36、 If the string is  null 、"" , Returns the default string 
        System.out.println(StringUtils.defaultIfEmpty(null, "default")); // default
        System.out.println(StringUtils.defaultIfEmpty("", "default")); // default
        System.out.println(StringUtils.defaultIfEmpty(" ", "default")); // " "
        // end
    }

}