Object类wait及notify方法原理实例解析

时间:2022-07-07 18:06:30

Object类中的waitnotify方法(生产者和消费者模式)  不是通过线程调用

  • wait():    让正在当前对象上活动的线程进入等待状态,无期限等待,直到被唤醒为止
  • notify():    让正在当前对象上等待的线程唤醒
  • notifyAll():   唤醒当前对象上处于等待的所有线程

生产者和消费者模式 生产线程和消费线程达到均衡

wait方法和notify方法建立在synchronized线程同步的基础之上

  • wait方法:   释放当前对象占有的锁
  • notify方法:   通知,不会释放锁

实现生产者和消费者模式  仓库容量为10

代码如下

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import java.util.ArrayList;
 
public class Test_14 {
  public static void main(String[] args) {
    ArrayList list = new ArrayList();
    Thread t1 = new Thread(new ProducerThread(list));
    t1.setName("producer");
    Thread t2 = new Thread(new ConsumerThread(list));
    t2.setName("consumer");
    t1.start();
    t2.start();
  }
}
//生产者线程
class ProducerThread implements Runnable{
  private ArrayList arrayList;
 
  public ProducerThread(ArrayList arrayList) {
    this.arrayList = arrayList;
  }
 
  @Override
  public void run() {
    while (true) {
      synchronized (arrayList) {
        if (arrayList.size() > 9){
          try {
            arrayList.wait();
          } catch (InterruptedException e) {
            e.printStackTrace();
          }
        }
        try {
          Thread.sleep(1000);
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
        arrayList.add(new Object());
        System.out.println(Thread.currentThread().getName() + "---> 生产" + "---库存" + arrayList.size());
        arrayList.notify();
      }
    }
  }
}
 
//消费者线程
class ConsumerThread implements Runnable{
  private ArrayList arrayList;
 
  public ConsumerThread(ArrayList arrayList) {
    this.arrayList = arrayList;
  }
 
  @Override
  public void run() {
    while (true){
      synchronized (arrayList){
        if (arrayList.size() < 9){
          try {
            arrayList.wait();
          } catch (InterruptedException e) {
            e.printStackTrace();
          }
        }
        try {
          Thread.sleep(1000);
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
        arrayList.remove(0);
        System.out.println(Thread.currentThread().getName() + "---> 消费" + "---库存" + arrayList.size());
        arrayList.notify();
      }
    }
  }
}

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原文链接:https://www.cnblogs.com/llcy/p/13468480.html