//阻塞隊(duì)列BlockQueue
static class BlockQueue{
    //該隊(duì)列用一個(gè)數(shù)組來實(shí)現(xiàn)，我們讓此隊(duì)列的最大容量為10
        private int[] items = new int[10];
        private int head = 0;
        private int tail = 0;
        private int size = 0;
        private Object locker =new Object();
        //入隊(duì)
        public void put(int item) throws InterruptedException {
            synchronized(locker) {
                while (size == items.length) {
                    //入隊(duì)時(shí)，若隊(duì)滿，阻塞
                    locker.wait();
                }
                items[tail++] = item;
                //如果到達(dá)末尾，重回隊(duì)首（實(shí)現(xiàn)循環(huán)隊(duì)列）
                if (tail >= items.length) {
                    tail = 0;
                }
                size++;
                locker.notify();
            }
        }
        //出隊(duì)
        public int back() throws InterruptedException {
            int ret = 0;
            synchronized (locker) {
                while (size == 0) {
                    //出隊(duì)時(shí)，若隊(duì)空，阻塞
                    locker.wait();
                }
                ret = items[head++];
                if (head >= items.length) {
                    head = 0;
                }
                size--;
                locker.notify();
            }
            return ret;
        }
    }

public static void main(String[] args) throws InterruptedException {
        BlockQueue blockQueue = new BlockQueue();
        //生產(chǎn)者線程
        Thread produce = new Thread(){
            @Override
            public void run() {
                for(int i = 0;i<10000;++i){
                    try {
                        System.out.println("生產(chǎn)了:"+i);
                        blockQueue.put(i);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        };
        produce.start();
        //消費(fèi)者線程
        Thread customer = new Thread(){
            @Override
            public void run() {
                while (true) {
                    try {
                        int res = blockQueue.back();
                        System.out.println("消費(fèi)了：" + res);
                        //每次消費(fèi)后等1秒，也就是生產(chǎn)的快，消費(fèi)的慢
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        };
        customer.start();
        customer.join();
        produce.join();
    }

import java.util.Timer;
import java.util.TimerTask;
public class Test{
public static void main(String[] args) {
        Timer timer = new Timer();
        System.out.println("代碼開始執(zhí)行");
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                System.out.println("觸發(fā)定時(shí)器");
            }
        },3000);
    }
}

//Task類用來描述任務(wù)，它繼承Comparable接口是因?yàn)橐獙⑷蝿?wù)放到優(yōu)先級阻塞隊(duì)列中
    static class Task implements Comparable<Task>{
        //command表示這個(gè)任務(wù)是什么
        private Runnable command;
        //time是一個(gè)時(shí)間戳
        private long time;
        public Task(Runnable command,long time){
            this.command = command;
            this.time = System.currentTimeMillis()+time;
        }
        public void run(){
            command.run();
        }
        //因?yàn)橐獙ask任務(wù)放到優(yōu)先級阻塞隊(duì)列中，所以要重寫compareTo方法，我們將時(shí)間短的任務(wù)放到隊(duì)頭
        @Override
        public int compareTo(Task o) {
            return (int)(this.time - o.time);
        }
    }

//Timer類中需要有一個(gè)定時(shí)器，還需要有一個(gè)schedule方法
    static class Timer{
        //使用優(yōu)先級阻塞隊(duì)列來放這些任務(wù)，這樣才能把最接近時(shí)鐘的任務(wù)放到隊(duì)頭，我們每次掃描隊(duì)頭任務(wù)就行了
        private PriorityBlockingQueue<Task> queue = new PriorityBlockingQueue<>();
        //locker用來解決忙等問題
        private Object locker = new Object();
        //構(gòu)造方法中完成定時(shí)器功能
        public Timer(){
            //需要構(gòu)造一個(gè)線程，來不斷地掃描隊(duì)頭，來判斷隊(duì)頭任務(wù)是否到點(diǎn)，也就是是否該開始執(zhí)行了
            Thread t = new Thread(){
                @Override
                public void run() {
                    while(true){
                        //取出隊(duì)首任務(wù)來判斷是否到時(shí)間了
                        try {
                            Task task = queue.take();
                            long current = System.currentTimeMillis();
                            //當(dāng)前時(shí)間戳小于時(shí)鐘時(shí)間戳，表明時(shí)間還沒到,那就等待
                            if (current < task.time){
                                queue.put(task);
                                synchronized (locker){
                                    locker.wait(task.time-current);
                                }
                            }else{
                                //否則時(shí)間到，開始執(zhí)行任務(wù)
                                task.run();
                            }
                        } catch (InterruptedException e) {
                                e.printStackTrace();
                                break;
                            }
                        }
                    }
                };
            t.start();
            }
        //schedule方法的兩個(gè)參數(shù)，command為任務(wù)，delay為一個(gè)時(shí)間差例如：3000(單位為毫秒)
        public void schedule(Runnable command,long delay){
            Task task = new Task(command,delay);
            queue.put(task);
            synchronized (locker){
                locker.notify();
            }
        }
    }

public static void main(String[] args) {
        System.out.println("程序啟動(dòng)");
        Timer timer = new Timer();
        timer.schedule(new Runnable() {
            @Override
            public void run() {
                System.out.println("觸發(fā)定時(shí)器");
            }
        },3000);//3000表示定時(shí)時(shí)間為3秒
    }