多线程9--- 线程间非实时通信--锁的wait与notify

Posted 2020-10-16 黑土白云

1.

 1 public class ListAdd1 {
 2     private volatile static List list = new ArrayList();
 3     
 4     public void add(){
 5         list.add("hello");
 6     }
 7     
 8     public int size(){
 9         return list.size();
10     }
11     
12     public static void main(String[] args) {
13         final ListAdd1 list1 = new ListAdd1();
14         final Object lock = new Object();
15         Thread t1 = new Thread(new Runnable() {
16             @Override
17             public void run() {
18                 synchronized (lock) {//对象锁
19                     try {
20                         for (int i = 0; i < 10; i++) {
21                             list1.add();
22                             System.out.println(Thread.currentThread().getName()+"添加了一个元素...");
23                             Thread.sleep(100);
24                             
25                             if(list1.size() == 5) {
26                                 System.out.println("发出唤醒通知..");
27                                 lock.notify();//不释放当前线程的锁lock, 当前线程继续执行
28                             }
29                         }
30                     } catch (Exception e) {
31                         e.printStackTrace();
32                     }
33                 }
34                 
35             }
36         }, "t1");
37         
38         Thread t2 = new Thread(new Runnable() {
39             @Override
40             public void run() {
41                 synchronized (lock) { //对象锁
42                     if(list1.size() != 5){
43                         try {
44                             lock.wait(); //释放锁
45                         } catch (InterruptedException e) {
46                             e.printStackTrace();
47                         }
48                         System.out.println(Thread.currentThread().getName()+"线程停止");
49                         throw new RuntimeException();
50                     }
51                 }
52             }
53         }, "t2");
54         
55         t2.start(); //先t2监听,不等于释放锁,被t1拿到,t1加到5发通知,继续等到执行完, t2开始执行!
56         t1.start();
57         
58       /*t1添加了一个元素...
59         t1添加了一个元素...
60         t1添加了一个元素...
61         t1添加了一个元素...
62         t1添加了一个元素...
63         发出唤醒通知..
64         t1添加了一个元素...
65         t1添加了一个元素...
66         t1添加了一个元素...
67         t1添加了一个元素...
68         t1添加了一个元素...
69         t2线程停止
70         Exception in thread "t2" java.lang.RuntimeException
71             at com.bjsxt.base.thread06.ListAdd1$2.run(ListAdd1.java:54)
72             at java.lang.Thread.run(Thread.java:744)*/
73     }
74 }

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