多线程交替打印红绿灯

用多线程交替打印红绿灯

用到的技术有

new Thread(new Runnable()).start();

ReentranLock

Condition

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

public class TestReentrantLock {

	private static Lock lock = new ReentrantLock();
	private static Condition aCondition = lock.newCondition();
	private static Condition bCondition = lock.newCondition();

	public static void main(String[] args) {
		Runnable a = new Runnable() {
			@Override
			public void run() {
				while (true) {
					lock.lock();
					try {
						System.out.println("红灯");
						Thread.sleep(1000);
						bCondition.signal();
						aCondition.await();
					} catch (Exception e) {
						e.printStackTrace();
					} finally {
						lock.unlock();
					}
				}
			}
		};

		Runnable b = new Runnable() {
			@Override
			public void run() {
				while (true) {
					lock.lock();
					try {
						System.out.println("绿灯");
						Thread.sleep(1000);
						aCondition.signal();
						bCondition.await();
					} catch (Exception e) {
						e.printStackTrace();
					} finally {
						lock.unlock();
					}
				}
			}
		};
		new Thread(a).start();
		new Thread(b).start();
	}
}