使用ReenTrantLock+Condition实现精准唤醒线程

太过爱你忘了你带给我的痛 2022-05-23 21:30 169阅读 0赞

以前我们wait/notify notifyAll来实现线程的等待唤醒机制，可是notify 并不能精准地帮我唤醒我们想要唤醒的那个进程，这是可以使用ReenTrantLock+Condition来实现精准唤醒一个线程，每一个线程都会有一个Condition对象对唤醒。  
直接上代码：

package com.richinfo.cn.reentrantlock;
    
    import java.util.concurrent.locks.Condition;
    import java.util.concurrent.locks.ReentrantLock;
    
    /** * @author : Allen(Wu Zhiwei) * @date 创建时间：2018年5月18日 上午11:33:28 * @version 1.0 * @parameter * @since * @return */
    public class MyService {
        private ReentrantLock lock = new ReentrantLock();
        private Condition ca = lock.newCondition();
        private Condition cb = lock.newCondition();
    
        public void awaitA(){
            try{
                lock.lock();
                System.out.println(Thread.currentThread().getName() + ",start waitA");
                ca.await();
                System.out.println(Thread.currentThread().getName() + ",end waitA");
            } catch (InterruptedException e){
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    
        public void awaitB(){
            try{
                lock.lock();
                System.out.println(Thread.currentThread().getName() + ",start waitB");
                cb.await();
                System.out.println(Thread.currentThread().getName() + ",end waitB");
            } catch (InterruptedException e){
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    
        public void singnalA(){
            try{
                lock.lock();
                ca.signal();
                System.out.println(Thread.currentThread().getName() + ",singnal A");
            } finally {
                lock.unlock();
            }
        }
    }

测试类：

package com.richinfo.cn.reentrantlock;
    /** * @author : Allen(Wu Zhiwei) * @date 创建时间：2018年5月18日 上午11:31:11 * @version 1.0 * @parameter * @since * @return */
    public class Run { 
    
        /** * @param args */
        public static void main(String[] args) {
            // TODO Auto-generated method stub
            final MyService service = new MyService();
            Runnable ra = new Runnable(){
    
                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    service.awaitA();
    
                }
    
            };
            Runnable rb = new Runnable(){
    
                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    service.awaitB();
    
                }
    
            };
            Thread threadA =new Thread(ra);
            Thread threadB =new Thread(rb);
            threadA.setName("A");
            threadB.setName("B");
            threadA.start();
            threadB.start();
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            service.singnalA();
        }
    }

控制台输出：  
A,start waitA  
B,start waitB  
main,singnal A  
A,end waitA