可重入锁的使用，指定等待和唤醒指定的线程

package com.zl.reentranlock;

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

/**
 * 
 * @author 丢了风筝的线
 * @see 测试可重入锁/互斥锁，可以让指定的线程等待或者唤醒指定的线程
 * @see 2019年12月25日
 */
public class ReentranLockTest {
	public static void main(String[] args) {
		final Print1 p = new Print1();
		new Thread() {

			@Override
			public void run() {
				while (true) {
					try {
						p.print1();
					} catch (InterruptedException e) {

						e.printStackTrace();
					}
				}
			}
		}.start();
		new Thread() {

			@Override
			public void run() {
				while (true) {
					try {
						p.print2();
					} catch (InterruptedException e) {

						e.printStackTrace();
					}
				}
			}
		}.start();

		new Thread() {

			@Override
			public void run() {
				while (true) {
					try {
						p.print3();
					} catch (InterruptedException e) {

						e.printStackTrace();
					}
				}
			}
		}.start();

	}

}

class Print1 {

	int flag = 1;

	// 获取可从入锁对象
	private final ReentrantLock lock = new ReentrantLock();

	// 获取标识线程锁对象
	final Condition c1 = lock.newCondition();
	final Condition c2 = lock.newCondition();
	final Condition c3 = lock.newCondition();

	public void print1() throws InterruptedException {
		lock.lock();
		if (flag != 1) {

			// 使指定的线程等待
			c1.await();
		}
		System.out.print("人");
		System.out.print("生");
		System.out.print("在");
		System.out.print("世");
		System.out.println();

		// 更改标记
		flag = 2;

		// 唤醒指定的线程
		c2.signal();

		// 释放锁
		lock.unlock();

	}

	public void print2() throws InterruptedException {
		lock.lock();
		if (flag != 2) {
			c2.await();
		}
		System.out.print("不");
		System.out.print("论");
		System.out.print("当");
		System.out.print("下");
		System.out.print("你");
		System.out.print("我");
		System.out.println();
		flag = 3;
		c3.signal();
		lock.unlock();
	}

	public void print3() throws InterruptedException {
		lock.lock();
		if (flag != 3) {
			c3.await();
		}
		System.out.print("当");
		System.out.print("会");
		System.out.print("峰");
		System.out.print("独");
		System.out.print("行");
		System.out.print("为");
		System.out.print("红");
		System.out.print("颜");
		System.out.println();
		flag = 1;
		c1.signal();
		lock.unlock();
	}

}