java-base-maven/springboot-main/src/main/java/com/alvin/util/StopWatch.java

package com.alvin.util;

class StopWatch {
    private String name = "";
    private long startTime;

    public StopWatch() {
        startTime = System.currentTimeMillis();
    }

    public StopWatch(String name) {
        this();
        this.name = name;
    }

    public String stop() {
        long endTime = System.currentTimeMillis();
        long spendTime = endTime - this.startTime;
        String s = DateUtil.formatTime(spendTime);
        System.out.println(this.name + " 用时：" + s);
        return s;
    }

    public static void main(String[] args) throws InterruptedException {
        StopWatch stopWatch = new StopWatch("A");
        Thread.sleep(100);
        stopWatch.stop();
    }
}