测试程序运行时间

程序本体

package com.yue.util;
import java.time.LocalDateTime;
public class TimeUtil {
    public interface Task {
        void execute();
    }
    public static void check(String title, Task task) {
        if (task == null) {
            return;
        }
        title = (title == null) ? "" : ("[" + title + "]");
        System.out.println(title);
        System.out.println("开始：" + LocalDateTime.now());
        long beginTime = System.currentTimeMillis();
        task.execute();
        long endTime = System.currentTimeMillis();
        System.out.println("结束：" + LocalDateTime.now());
        double delta = (endTime - beginTime) / 1000.0;
        System.out.println("耗时：" + delta + "秒");
        System.out.println("=========");
    }
}

调用

package com.yue;
import com.yue.util.TimeUtil;
public class Main {
    public static void main(String[] args) {
        TimeUtil.check("testAdd", new TimeUtil.Task() {
            @Override
            public void execute() {
                long res = 0;
                for (long i = 0; i < 1000000000; i ++) {
                    res += i;
                }
                System.out.println(res);
            }
        });
    }
}

运行结果