apache的replace,trim方法 StringUtils.replace(),StringUtils.trimWhitespace() java原生

apache的replace,trim方法 StringUtils.replace(),StringUtils.trimWhitespace() 
java原生的replace,trim方法之间性能的巨大差别。 

Java代码  

1. public class App   
2. {  
3.     final static String teString = "    555555599999999999999999aaa sss ssaaaaaaaaaaaaaatasdtatastasrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa      ";   
4.     public static void main( String[] args )  
5.     {  
6.         int t = 100000;  
7.          long start1 = System.nanoTime();  
8.          long stringUtilsReplaceTime = 0;  
9.          long stringUtilsTrimTime = 0;  
10.          long stringReplaceTime = 0;  
11.          long stringTrimTime = 0;  
12.          for(int i= 0;i<t;i++){  
13.            StringUtils.replace(teString,"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","b");  
14.          }  
15.          stringUtilsReplaceTime= System.nanoTime()-start1;  
16.            
17.            
18.           start1 = System.nanoTime();  
19.          for(int i= 0;i<t;i++){  
20.            teString.replace("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "b");  
21.          }  
22.            
23.          stringReplaceTime = System.nanoTime()-start1;  
24.   
25.         start1 = System.nanoTime();  
26.        for(int i= 0;i<t;i++){  
27.            teString.trim();  
28.        }  
29.        stringTrimTime = System.nanoTime()-start1;  
30.          
31.          
32.         start1 = System.nanoTime();  
33.        for(int i= 0;i<t;i++){  
34.             
35.            StringUtils.trimWhitespace(teString);  
36.        }  
37.          
38.        stringUtilsTrimTime = System.nanoTime()-start1;  
39.          
40.        System.out.println("stringUtilsReplaceTime:"+stringUtilsReplaceTime);  
41.        System.out.println("stringReplaceTime     :"+stringReplaceTime);  
42.        System.out.println("stringUtilsTrimTime   :"+stringUtilsTrimTime);  
43.        System.out.println("stringTrimTime        :"+stringTrimTime);  
44.     }  
45.    
46. }  

输出结果为： 
stringUtilsReplaceTime:293389595 
stringReplaceTime     :1019421816 
stringUtilsTrimTime   :176730378 
stringTrimTime        :3888271 

Java代码  

1. public class App   
2. {  
3.     final static String teString = "    555555599999999999999999aaa sss ssaaaaaaaaaaaaaatasdtatastasrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa      ";   
4.     public static void main( String[] args )  
5.     {  
6.         int t = 100;  
7.          long start1 = System.nanoTime();  
8.          long stringUtilsReplaceTime = 0;  
9.          long stringUtilsTrimTime = 0;  
10.          long stringReplaceTime = 0;  
11.          long stringTrimTime = 0;  
12.          for(int i= 0;i<t;i++){  
13.            StringUtils.replace(teString,"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","b");  
14.          }  
15.          stringUtilsReplaceTime= System.nanoTime()-start1;  
16.            
17.            
18.           start1 = System.nanoTime();  
19.          for(int i= 0;i<t;i++){  
20.            teString.replace("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "b");  
21.          }  
22.            
23.          stringReplaceTime = System.nanoTime()-start1;  
24.   
25.         start1 = System.nanoTime();  
26.        for(int i= 0;i<t;i++){  
27.            teString.trim();  
28.        }  
29.        stringTrimTime = System.nanoTime()-start1;  
30.          
31.          
32.         start1 = System.nanoTime();  
33.        for(int i= 0;i<t;i++){  
34.             
35.            StringUtils.trimWhitespace(teString);  
36.        }  
37.          
38.        stringUtilsTrimTime = System.nanoTime()-start1;  
39.          
40.        System.out.println("stringUtilsReplaceTime:"+stringUtilsReplaceTime);  
41.        System.out.println("stringReplaceTime     :"+stringReplaceTime);  
42.        System.out.println("stringUtilsTrimTime   :"+stringUtilsTrimTime);  
43.        System.out.println("stringTrimTime        :"+stringTrimTime);  
44.     }  
45.    
46. }  

结果为： 
stringUtilsReplaceTime:94864540 
stringReplaceTime     :8341259 
stringUtilsTrimTime   :953821 
stringTrimTime        :57856