Examples of how to implement multi-threaded message queues in Java

This article mainly introduces the implementation code of java multi-threaded message queue. The editor thinks it is quite good. Now I will share it with you and give it as a reference. Let’s follow the editor and take a look.

This article introduces the implementation code of java multi-threaded message queue. I share it with you. I hope it will be helpful to everyone. By the way, I also leave a note for myself.

1. Define a queue buffer pool:

 //static修饰的成员变量和成员方法独立于该类的任何对象。也就是说，它不依赖类特定的实例，被类的所有实例共享。
private static List<Queue> queueCache = new LinkedList<Queue>();

2. Define the maximum number of messages in the queue buffer pool. If this value is reached, then the queue check-in will wait for the check-out below Continue with this value.

private Integer offerMaxQueue = 2000;

3. Define the checkout thread. If there is no message in the queue buffer pool, the checkout thread will be waiting.

new Thread(){
    public void run(){
     while(true){
      String ip = null;
      try {
       synchronized (queueCache) {
        Integer size = queueCache.size();
        if(size==0){
//队列缓存池没有消息，等待。。。。     queueCache.wait();
        }
        Queue queue = queueCache.remove(0);

        if(isIpLock(queueStr)){//假若这个是一个多应用的分布式系统，那么这个判断应该是分布式锁，这里说的锁不是线程停止，而是跳过该消息，滞后处理
         queueCache.add(queue);该queue重新加入队列缓冲池，滞后处理，
         continue;
        }else{
      ;//这里是处理该消息的操作。
        }
        size = queueCache.size();
        if(size<offerMaxQueue&&size>=0){     queueCache.notifyAll();//在队列缓存池不超过最大值的前提下，假若检入正在等待中，那么那么让他们排队检入。
        }
       }
      } catch (Exception e) {
       e.printStackTrace();
      }finally{
       try {//检出该消息队列的锁
        unIpLock(queueStr);
       } catch (Execption e) {//捕获异常，不能让线程挂掉
        e.printStackTrace();
       } 
                      }
      }
   }.start();

4. Check-in queue

synchronized (queueCache) {
while(true){
Integer size = queueCache.size();
if(size>=offerMaxQueue){
      try {
       queueCache.wait();
continue;//继续执行等待中的检入任务。
 } catch (InterruptedException e) {
   e.printStackTrace();
 }
 }//IF

if(size<=offerMaxQueue&&size>0){
 queueCache.notifyAll();
}
break;//检入完毕
}//while
}

5. Lock method implementation

/**
  * 锁
  * @param ip
  * @return
  * @throws 
  */
 public Boolean isLock(String queueStr) {
  return this.redisManager.setnx(queueStr+"_lock", "LOCK", 10000)!=1;
 }
 //解锁
 public void unIpLock(String queueStr) {
  if(ip!=null){
   this.redisManager.del(queueStr+"_lock");
//  lock.unlock();
  }
 }

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