线程之间的通讯的几种方式

1.通过while(true), 抛异常实现

public class ListAdd1 {
    private static volatile List<String> list = new ArrayList<String>();    
    
    public void add(){
        list.add("bjsxt");
    }
    public int size(){
        return list.size();
    }
    
    public static void main(String[] args) {
        
        final ListAdd1 list1 = new ListAdd1();
        
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    for(int i = 0; i <10; i++){
                        list1.add();
                        System.out.println("当前线程：" + Thread.currentThread().getName() + "添加了一个元素..");
                        Thread.sleep(500);
                    }    
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "t1");
        
        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                while(true){
                    if(list1.size() == 5){
                        System.out.println("当前线程收到通知：" + Thread.currentThread().getName() + " list size = 5 线程停止..");
                        throw new RuntimeException();
                    }
                }
            }
        }, "t2");        
        
        t2.start();
        t1.start();
    }
}  

2.通过wait, notify实现

3.通过CountDownLatch实现

public class ListAdd2 {
    private volatile static List list = new ArrayList();    
    
    public void add(){
        list.add("bjsxt");
    }
    public int size(){
        return list.size();
    }
    
    public static void main(String[] args) {
        
        final ListAdd2 list2 = new ListAdd2();
        
        // 1 实例化出来一个 lock
        // 当使用wait 和 notify 的时候 ， 一定要配合着synchronized关键字去使用
        final Object lock = new Object();
        
        final CountDownLatch countDownLatch = new CountDownLatch(1);
        
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    synchronized (lock) {
                        for(int i = 0; i <10; i++){
                            list2.add();
                            System.out.println("当前线程：" + Thread.currentThread().getName() + "添加了一个元素..");
                            Thread.sleep(500);
                            if(list2.size() == 5){
                                System.out.println("已经发出通知..");
//                                countDownLatch.countDown();
                                lock.notify();
                            }
                        }                        
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "t1");
        
        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (lock) {
                    if(list2.size() != 5){
                        try {
                            //System.out.println("t2进入...");
                            lock.wait();
                            countDownLatch.await();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    System.out.println("当前线程：" + Thread.currentThread().getName() + "收到通知线程停止..");
                    throw new RuntimeException();
                }
            }
        }, "t2");    
        
        t2.start();
        t1.start();
        
    }
    
}