一行代码引发的性能暴跌 10 倍

bigfish — Thu, 11 Mar 2021 10:00:00 +0800

代码测试

import com.google.common.base.Stopwatch;
import java.util.concurrent.TimeUnit;
public class StackTest {
    public static void main(String[] args) {
        Stopwatch started = new Stopwatch();
        started.start();
        User user = null;
        for (long i = 0; i < 1000_000_000; i++) {
            user = new User();
        }
        started.stop();
        System.out.println(started.elapsed(TimeUnit.MILLISECONDS) + "ms");
        //不加打印 300ms
        //加了打印 3000ms
//        System.out.println(user);
    }
}

class User {
    private int age;
    private String userName;

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }
}

bigfish的网络博客 - 性能

一行代码引发的性能暴跌 10 倍

代码测试