condition简单示例

最新推荐文章于 2022-04-28 18:30:18 发布

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最新推荐文章于 2022-04-28 18:30:18 发布

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CC 4.0 BY-SA版权

文章标签： java

原文链接：http://www.cnblogs.com/codechange/p/8990717.html

本文介绍如何利用Java并发包中的Condition接口实现精确线程唤醒，避免随机唤醒带来的不确定性和竞争问题。通过创建两个Condition实例并分别在不同线程中调用await()和signal()方法演示了这一过程。

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在concurrent包中提供了condition接口，通过该接口可唤醒指定的某个线程，而不是采用随机唤醒的形式。

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class LockTest {

    
    private static Lock lock = new ReentrantLock();
    private static Condition condition_1 = lock.newCondition();
    private static Condition condition_2 = lock.newCondition();
    
    public static void main(String[] args) throws InterruptedException {
        /*Lock lock = new ReentrantLock();
        Condition condition = lock.newCondition();
        
        new Thread(() -> runLockMethod(lock, 1000),"thread-1").start();
        new Thread(() -> runLockMethod(lock, 3000),"thread-2").start();
        new Thread(() -> runLockMethod(lock, 5000),"thread-3").start();*/
        
        
        LockTest test = new LockTest();
        new Thread(() -> test.lockwait(condition_1), "thread-1").start();
        new Thread(() -> test.lockwait(condition_2), "thread-2").start();
        Thread.sleep(3000);
        new Thread(() -> test.locksignal(condition_2), "thread-3").start();
        new Thread(() -> test.locksignal(condition_1), "thread-4").start();
    }

    /*private static void runLockMethod(Lock lock, long times) {
        lock.lock();
        try {
//            List<Integer> list = Arrays.asList(1,2,3);
            Thread.sleep(times);
            System.out.println(Thread.currentThread().getName());
//            list.forEach(System.out::println);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }*/
    
    private void lockwait(Condition condition) {
        lock.lock();
        try {
            System.out.println( Thread.currentThread().getName() +" start wait.......");
            condition.await();
            System.out.println( Thread.currentThread().getName() +" over wait.......");
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    
    private void locksignal(Condition condition) {
        lock.lock();
        try {
            System.out.println(Thread.currentThread().getName() + " start notify....");
            condition.signal();
        } finally {
            lock.unlock();
        }
    }
    
}