ArrayBlockingQueue做互斥让线程依次执行

柔情只为你懂 2023-05-31 04:58 3阅读 0赞

控制程序依次交替执行的办法之一：

package com.xxx.queue;
    import java.util.concurrent.ArrayBlockingQueue;
    import java.util.concurrent.BlockingQueue;
    public class BlockingQueueCommunication {
    	public static void main(String[] args) {
    		final Business business = new Business();
    		new Thread(){
    			public void run() {
    				for(int i=0;i<50;i++){
    					business.sub(i);
    				}
    			};
    		}.start();
    		
    		for(int i=0;i<50;i++){
    			business.main(i);
    		}
    	}
    	
    	static class Business{
    		BlockingQueue<Integer> queue1 = new ArrayBlockingQueue<Integer>(1);
    		BlockingQueue<Integer> queue2 = new ArrayBlockingQueue<Integer>(1);
    		
    		{
    			try {
    				queue2.put(1);
    			} catch (Exception e) {
    				e.printStackTrace();
    			}
    		}
    		
    		public void sub(int i){
    			try {
    				queue1.put(1);
    				
    			} catch (Exception e) {
    				e.printStackTrace();
    			}
    			for(int j=1;j<=10;j++){
    				System.out.println("sub thread queue of "+j+",loop of"+i);
    			}
    			try {
    				queue2.take();
    			} catch (Exception e) {
    				e.printStackTrace();
    			}
    		}
    		
    		public void main(int i){
    			try {
    				queue2.put(1);
    			} catch (Exception e) {
    				e.printStackTrace();
    			}
    			for(int j=1;j<=10;j++){
    				System.out.println("main thread queue of "+j+",loop of"+i);
    			}
    			try {
    				queue1.take();
    			} catch (Exception e) {
    				e.printStackTrace();
    			}
    		}
    	}
    }

运行程序，打印结果如下：

sub thread queue of 1,loop of 0
    sub thread queue of 2,loop of 0
    sub thread queue of 3,loop of 0
    sub thread queue of 4,loop of 0
    sub thread queue of 5,loop of 0
    sub thread queue of 6,loop of 0
    sub thread queue of 7,loop of 0
    sub thread queue of 8,loop of 0
    sub thread queue of 9,loop of 0
    sub thread queue of 10,loop of 0
    main thread queue of 1,loop of 0
    main thread queue of 2,loop of 0
    main thread queue of 3,loop of 0
    main thread queue of 4,loop of 0
    main thread queue of 5,loop of 0
    main thread queue of 6,loop of 0
    main thread queue of 7,loop of 0
    main thread queue of 8,loop of 0
    main thread queue of 9,loop of 0
    main thread queue of 10,loop of 0
    sub thread queue of 1,loop of 1
    sub thread queue of 2,loop of 1
    sub thread queue of 3,loop of 1
    sub thread queue of 4,loop of 1
    sub thread queue of 5,loop of 1
    sub thread queue of 6,loop of 1
    sub thread queue of 7,loop of 1
    sub thread queue of 8,loop of 1
    sub thread queue of 9,loop of 1
    sub thread queue of 10,loop of 1
    main thread queue of 1,loop of 1
    main thread queue of 2,loop of 1
    main thread queue of 3,loop of 1
    main thread queue of 4,loop of 1
    main thread queue of 5,loop of 1
    main thread queue of 6,loop of 1
    main thread queue of 7,loop of 1
    main thread queue of 8,loop of 1
    main thread queue of 9,loop of 1
    main thread queue of 10,loop of 1
    。。。。。。

打印信息没有贴完，完整结果可以猜想得到 ，后面依次是2,3,4。。。49循环结束。

这里巧妙地利用了阻塞队列的特点：有元素时，可以取出take，没有则等待，因为队列长度固定，只能放一个元素，所以队列满的，就不能插入put了，只能等待取出才能继续插入。

这里Business类的sub,main方法，每次在进行操作之前都做了一个可以执行的操作插入put，操作完成，将另一个队列的元素进行取出take，相当于锁功能的获取锁与释放锁。正好形成了一个互斥的效果，一个可以操作，另一个阻塞等待。