实例测试java的Integer转String的效率问题1.8

原文链接：https://blog.csdn.net/chicaohun7473/article/details/100851373

查看String源码时,读到源码的toString方法时,打算探究下几种转换的效率,网上查到该帖子时,

本地执行后发现结果与帖子并不相同,唯一的区别便是jdk的版本,故提出自己的结论!

测试环境：操作系统 windows 10，内存 8g，jdk 1.8，jvm参数是默认值，测试代码如下：

 1 public static void main(String[] args) {   
 2         Integer[] intArr = new Integer[2000000];   
 3         String[] strArr1 = new String[2000000];
 4         String[] strArr2 = new String[2000000];   
 5         String[] strArr3 = new String[2000000];   
 6         String[] strArr4 = new String[2000000];   
 7         Long t1 = System.currentTimeMillis();  
 8         for(int i = 0; i < 2000000; i++){   
 9             intArr[i] = i + 1;   
10         }   
11         Long t2 = System.currentTimeMillis();   
12         for(int i = 0; i < 2000000; i++){   
13             strArr1[i] = String.valueOf(intArr[i]);     
14         }   
15         Long t3 = System.currentTimeMillis();   
16         for(int i = 0; i < 2000000; i++){   
17             strArr2[i] = Integer.toString(intArr[i]);   
18         }   
19         Long t4 = System.currentTimeMillis();   
20         for(int i = 0; i < 2000000; i++){   
21             strArr3[i] = intArr[i] + "";   
22         }   
23         Long t5 = System.currentTimeMillis();   
24         for(int i = 0; i < 2000000; i++){   
25             strArr4[i] = (intArr[i]).toString();
26         } 
27         Long t6 = System.currentTimeMillis();   
28         System.out.println("t1 = " + t1);   
29         System.out.println("t2 = " + t2);   
30         System.out.println("t3 = " + t3);   
31         System.out.println("t4 = " + t4);   
32         System.out.println("t5 = " + t5);   
33         System.out.println("t6 = " + t6);  
34         System.out.println("赋值：" + (t2 - t1));   
35         System.out.println("String.valueOf(i)：" + (t3 - t2));   
36         System.out.println("Integer.toString(i)：" + (t4 - t3));   
37         System.out.println("i + \"\"：" + (t5 - t4));   
38         System.out.println("i.toString()：" + (t6 - t5));   
39     }

执行结果:

推荐使用 toString() 或者String.valueOf(i)方法。

原文地址：https://www.cnblogs.com/gilbertbright/p/11698642.html