java实现BlockingQueue队列

学习多线程的过程中用代码实现的BlockingQueue队列。

阻塞队列实现类。

package com.xtli.controller.thread;import java.util.LinkedList;public class BlockingQueueTest {LinkedList<String> BQList = new LinkedList<String>();private int size = 0;//队列大小private int count = 0;//队列计数器private Object obj = new Object();//同步对象public BlockingQueueTest(int size) {this.size = size;}public void inQueue(String str) {synchronized(obj) {System.out.println("线程"+Thread.currentThread().getName()+":"+str+"准备进入队列。。");if(this.size == count) {try {System.out.println("线程"+Thread.currentThread().getName()+":"+"队列已满，阻塞。。");obj.wait();//等待其他线程从队列中取值} catch (InterruptedException e) {e.printStackTrace();}}BQList.add(str);count++;System.out.println("线程"+Thread.currentThread().getName()+":"+str+"成功进入队列。。");System.out.println("当前队列中的值为:"+BQList.toString());obj.notifyAll();//通知等待的其他线程}}public String outQueue() {synchronized(obj) {System.out.println("线程"+Thread.currentThread().getName()+":"+"准备从队列中取值。。");if(this.count == 0) {try {System.out.println("线程"+Thread.currentThread().getName()+":"+"队列已空，阻塞。。");obj.wait();//等待其他线程，往队列里塞值} catch (InterruptedException e) {e.printStackTrace();}}count--;String str = BQList.pollFirst();System.out.println("线程"+Thread.currentThread().getName()+":"+str+"成功出队列。。");System.out.println("当前队列中的值为:"+BQList.toString());obj.notifyAll();//通知等待的其他线程return str;}}}

启用两个线程，一个线程向队列中塞值，另外一个从队列中取值。

package com.xtli.controller.thread;public class BlockingQueueMain {static BlockingQueueTest BQ = new BlockingQueueTest(3);static class BlockingQueueInQueue extends Thread {public void run() {for(int i=0;i<5;i++) {//向队列中塞了5个值BQ.inQueue(String.valueOf(i));}}}static class BlockingQueueOutQueue extends Thread {public void run() {for(int i=0;i<6;i++) {//从队列中取了6个值BQ.outQueue();}}}public static void main(String[] args) throws InterruptedException {/*final BlockingQueueTest BQ = new BlockingQueueTest(3);BQ.inQueue("1");BQ.inQueue("2");BQ.inQueue("3");Thread t1 = new Thread(new Runnable() {@Overridepublic void run() {BQ.inQueue("4");BQ.inQueue("5");}});Thread t2 = new Thread(new Runnable() {@Overridepublic void run() {String str1 = BQ.outQueue();System.out.println(str1);String str2 = BQ.outQueue();System.out.println(str2);}});t1.start();Thread.sleep(1000);t2.start();*/new BlockingQueueInQueue().start();new BlockingQueueOutQueue().start();}}

        在BlockingQueueMain中，BlockingQueueInQueue向队列中塞了5次值，而BlockingQueueOutQueue从队列中取了6次，前5次均能正常取出，当第6次再次取值时，因为此时队列已空，此线程会一直处于等待状态。

        BlockingQueueOutQueue如果循环5次从队列中取值，如下

     BlockingQueueInQueue如果循环6次，BlockingQueueOutQueue循环5次，结果如下。