生产者消费者模式+等待+通知唤醒

刺骨的言语ヽ痛彻心扉 2022-12-17 07:30 143阅读 0赞

## 线程调用资源类 ##

public class ThreadDemo03 {
         public static void main(String [] args){
          final ShareData sd = new ShareData();
          FutureTask ft = new FutureTask(new Callable(){
                  @Override
                  public Object call() throws Exception {
                       for(int i=1;i<=10;i++){
                            try {
                                 sd.increment();
                            } catch (Exception e) {
                                 e.printStackTrace();
                            }
                       }
                       return null;
                  }
          });
          new Thread(ft,"aaa").start();
          FutureTask ft2 = new FutureTask(new Callable(){
                  @Override
                  public Object call() throws Exception {
                       for(int i=1;i<=10;i++){
                            try {
                                 sd.decrement();
                            } catch (Exception e) {
                                 e.printStackTrace();
                            }
                       }
                       return null;
                  }
          });
          new Thread(ft2,"bbb").start();
         }
    }

## 方式一：资源类用synchronized同步:  ##

class ShareData{
         private int number = 0;
         public synchronized void increment() throws InterruptedException {
              while(number != 0){  //此处不能用if(number !=0){},线程一多就会出问题
                  this.wait();
              }
              ++number;
              System.out.println(Thread.currentThread().getName()+"---"+number);
              this.notifyAll();
         }
         public synchronized void decrement() throws InterruptedException{
              while(number == 0){
                  this.wait();
              }
              --number;
              System.out.println(Thread.currentThread().getName()+"----"+number);
              this.notifyAll();
         }
    }

## 方式二：资源类用Lock同步：重点 ##

class ShareData{
         private int number = 0;
         private Lock lock = new ReentrantLock();
         private Condition cod = lock.newCondition();
         public void increment(){
              lock.lock();
              try {
                  while(number != 0){
                       cod.await();
                  }
                  ++number;
                  System.out.println(Thread.currentThread().getName()+"---"+number);
                cod.signalAll();
              } catch (Exception e) {
                  e.printStackTrace();
              }finally{
                  lock.unlock();
              }
         }
         public void decrement(){
              lock.lock();
              try {
                  while(number == 0){
                       cod.await();
                  }
                  --number;
                   System.out.println(Thread.currentThread().getName()+"---"+number);
                  cod.signalAll();
              } catch (Exception e) {
                  e.printStackTrace();
              }finally{
                  lock.unlock();
              }
         }