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：

 public static void main(String[] args) {
         Integer[] intArr = new Integer[2000000];
         String[] strArr1 = new String[2000000];
         String[] strArr2 = new String[2000000];
         String[] strArr3 = new String[2000000];
         String[] strArr4 = new String[2000000];
         Long t1 = System.currentTimeMillis();
         for(int i = 0; i < 2000000; i++){
             intArr[i] = i + 1;
         }
         Long t2 = System.currentTimeMillis();
         for(int i = 0; i < 2000000; i++){
             strArr1[i] = String.valueOf(intArr[i]);
         }
         Long t3 = System.currentTimeMillis();
         for(int i = 0; i < 2000000; i++){
             strArr2[i] = Integer.toString(intArr[i]);
         }
         Long t4 = System.currentTimeMillis();
         for(int i = 0; i < 2000000; i++){
             strArr3[i] = intArr[i] + "";
         }
         Long t5 = System.currentTimeMillis();
         for(int i = 0; i < 2000000; i++){
             strArr4[i] = (intArr[i]).toString();
         }
         Long t6 = System.currentTimeMillis();
         System.out.println("t1 = " + t1);
         System.out.println("t2 = " + t2);
         System.out.println("t3 = " + t3);
         System.out.println("t4 = " + t4);
         System.out.println("t5 = " + t5);
         System.out.println("t6 = " + t6);
         System.out.println("赋值：" + (t2 - t1));
         System.out.println("String.valueOf(i)：" + (t3 - t2));
         System.out.println("Integer.toString(i)：" + (t4 - t3));
         System.out.println("i + \"\"：" + (t5 - t4));
         System.out.println("i.toString()：" + (t6 - t5));
     }

执行结果:

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