java 实现线程间通信

1、使用线程池管理线程。

2、使用synchronized实现线程间同步。

3、使用wait()方法让当前线程等待；使用notify()方法唤起wait中的线程。

4、使用CountDownLatch等待线程结束。

上代码

package com.thread;
 
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
 
public class TasksCommunicate extends Thread {
    private static final int size = 12;
    private static StringBuilder sb = new StringBuilder();
    private static Integer num = 0;
    private String name;
    private CountDownLatch countDownLatch;
 
    public TasksCommunicate(String name, CountDownLatch countDownLatch) {
        this.name = name;
        this.countDownLatch = countDownLatch;
    }
 
    @Override
    public void run() {
        while (num < size) {
            synchronized (TasksCommunicate.class) {
                num = num + 1;
                System.out.println("thread_" + name + " 打印：" + sb.toString());
                sb = new StringBuilder("thread_" + name + "已完成自增1，目前num=" + num + "，请知晓！");
                TasksCommunicate.class.notify();
                try {
                    if (num < size) {
                        TasksCommunicate.class.wait();
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
        countDownLatch.countDown();
        System.out.println("thread_" + name + " 结束!");
    }
 
    public static void main(String[] args) {
        CountDownLatch countDownLatch = new CountDownLatch(2);
        Thread thread0 = new TasksCommunicate("A", countDownLatch);
        Thread thread1 = new TasksCommunicate("B", countDownLatch);
 
        ExecutorService executor = Executors.newFixedThreadPool(2);
 
        executor.submit(thread0);
        executor.submit(thread1);
 
        try {
            countDownLatch.await(3, TimeUnit.SECONDS);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
 
        executor.shutdown();
        System.out.println("进程结束，退出!!!");
    }
}

打印输出：

thread_A 打印：
thread_B 打印：thread_A已完成自增1，目前num=1，请知晓！
thread_A 打印：thread_B已完成自增1，目前num=2，请知晓！
thread_B 打印：thread_A已完成自增1，目前num=3，请知晓！
thread_A 打印：thread_B已完成自增1，目前num=4，请知晓！
thread_B 打印：thread_A已完成自增1，目前num=5，请知晓！
thread_A 打印：thread_B已完成自增1，目前num=6，请知晓！
thread_B 打印：thread_A已完成自增1，目前num=7，请知晓！
thread_A 打印：thread_B已完成自增1，目前num=8，请知晓！
thread_B 打印：thread_A已完成自增1，目前num=9，请知晓！
thread_A 打印：thread_B已完成自增1，目前num=10，请知晓！
thread_B 打印：thread_A已完成自增1，目前num=11，请知晓！
thread_A 结束!
thread_B 结束!
进程结束，退出!!!