Condition的使用

ReentrantLock与Condition一起使用可以更灵活、更方便的控制线程之间的等待唤醒操作。

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

public class UseCondition {

	private Lock reentrantLock = new ReentrantLock();
	private Condition condition1 = reentrantLock.newCondition();
	private Condition condition2 = reentrantLock.newCondition();
	
	public void m1() {
		reentrantLock.lock();
		try {
			System.err.println(\"线程 \" + Thread.currentThread().getName() + \" 已经进入执行等待。。。\");
			condition1.await();
			System.err.println(\"线程 \" + Thread.currentThread().getName() + \" 已被唤醒，继续执行。。。\");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			reentrantLock.unlock();
		}
	}
	public void m2() {
		reentrantLock.lock();
		try {
			System.err.println(\"线程 \" + Thread.currentThread().getName() + \" 已经进入执行等待。。。\");
			condition1.await();
			System.err.println(\"线程 \" + Thread.currentThread().getName() + \" 已被唤醒，继续执行。。。\");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			reentrantLock.unlock();
		}
	}
	public void m3() {
		reentrantLock.lock();
		try {
			System.err.println(\"线程 \" + Thread.currentThread().getName() + \" 已经进入执行等待。。。\");
			condition2.await();
			System.err.println(\"线程 \" + Thread.currentThread().getName() + \" 已被唤醒，继续执行。。。\");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			reentrantLock.unlock();
		}
	}
	public void m4() {
		reentrantLock.lock();
		try {
			System.err.println(\"线程 \" + Thread.currentThread().getName() + \" 已经进入发出condition1唤醒信号。。。\");
			condition1.signalAll();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			reentrantLock.unlock();
		}
	}
	public void m5() {
		reentrantLock.lock();
		try {
			System.err.println(\"线程 \" + Thread.currentThread().getName() + \" 已经进入发出condition2唤醒信号。。。\");
			condition2.signalAll();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			reentrantLock.unlock();
		}
	}
	
	public static void main(String[] args) {
		UseCondition useCondition = new UseCondition();
		Thread t1 = new Thread(new Runnable() {
			@Override
			public void run() {
				useCondition.m1();
			}
		},\"t1\");
		Thread t2 = new Thread(new Runnable() {
			@Override
			public void run() {
				useCondition.m2();
			}
		},\"t2\");
		Thread t3 = new Thread(new Runnable() {
			@Override
			public void run() {
				useCondition.m3();
			}
		},\"t3\");
		Thread t4 = new Thread(new Runnable() {
			@Override
			public void run() {
				useCondition.m4();
			}
		},\"t4\");
		Thread t5 = new Thread(new Runnable() {
			@Override
			public void run() {
				useCondition.m5();
			}
		},\"t5\");
		
		t1.start();
		t2.start();
		t3.start();
		try {
			Thread.sleep(2000);
		} catch (Exception e) {
			e.printStackTrace();
		}
		t4.start();
		try {
			Thread.sleep(2000);
		} catch (Exception e) {
			e.printStackTrace();
		}
		t5.start();
	}
}

程序执行结果：

t1、t2、t3线程先执行，休眠2秒钟后，t4执行，唤醒t1、t2，t1、t2继续执行，休眠2秒钟后，t5执行，唤醒t3，t3继续执行。