概念

防抖(debounce)

当持续触发事件时，一定时间段内没有再触发事件，事件处理函数才会执行一次，如果设定时间到来之前，又触发了事件，就重新开始延时

节流(throttle)

当持续触发事件时，保证在一定时间内只调用一次事件处理函数，意思就是说，假设一个用户一直触发这个函数，且每次触发小于既定值，函数节流会每隔这个时间调用一次

区别

防抖是将多次执行变为最后一次执行，节流是将多次执行变为每隔一段时间执行

Java实现

防抖(debounce)

public class DebounceTask {
    private Timer timer;
    private Long delay;
    private Runnable runnable;

    public DebounceTask(Runnable runnable,  Long delay) {
        this.runnable = runnable;
        this.delay = delay;
    }

    public static DebounceTask build(Runnable runnable, Long delay){
        return new DebounceTask(runnable, delay);
    }

    public void run(){
        if(timer!=null){
            timer.cancel();
        }
        timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                timer=null;
                runnable.run();
            }
        }, delay);
    }
}

节流(throttle)

public class ThrottleTask {
    private Timer timer;
    private Long delay;
    private Runnable runnable;
    private boolean needWait=false;

    public ThrottleTask(Runnable runnable,  Long delay) {
        this.runnable = runnable;
        this.delay = delay;
        this.timer = new Timer();
    }

    public static ThrottleTask build(Runnable runnable, Long delay){
        return new ThrottleTask(runnable, delay);
    }

    public void run(){
        if(!needWait){
            needWait=true;
            timer.schedule(new TimerTask() {
                @Override
                public void run() {
                    needWait=false;
                    runnable.run();
                }
            }, delay);
        }
    }
}

测试

防抖(debounce)

DebounceTask task = DebounceTask.build(new Runnable() {
    @Override
    public void run() {
        System.out.println("do task: "+System.currentTimeMillis());
    }
},1000L);
long delay = 100;
while (true){
    System.out.println("call task: "+System.currentTimeMillis());
    task.run();
    delay+=100;
    try {
        Thread.sleep(delay);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

节流(throttle)

ThrottleTask task = ThrottleTask.build(new Runnable() {
    @Override
    public void run() {
        System.out.println("do task: "+System.currentTimeMillis());
    }
},1000L);
while (true){
    System.out.println("call task: "+System.currentTimeMillis());
    task.run();
    try {
        Thread.sleep(200);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}