Lock中实现线程的精确唤醒（使多个线程按指定的顺序执行）

lock中类似wait和notify的方法：
await和signal/signalAll

原理：lock中使用Condition类做为锁监视器，调用Condition的await()和signal()实现线程的等待和唤醒。

实现代码：

Lock lock=new ReentrantLock();
Condition condition=lock.newCondition();
lock.lock();
try{
    while(...){
    condition.await();
    }
    condition.signalAll();
}catch(Exception e){
    
}finally{
    lock.unlock();
}

和wait/notifyAll相比的好处：

能够精准的唤醒指定的线程

多线程按顺序执行的实现：

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

public class OrderThread {
	
	public static void main(String[]args) {
		Order order=new Order();
		Thread thread1=new Thread(()->{
			for(int i=0;i<10;i++) {
				order.print1();
			}
		},"线程1");
		Thread thread2=new Thread(()->{
			for(int i=0;i<10;i++) {
				order.print2();
			}
		},"线程2");
		Thread thread3=new Thread(()->{
			for(int i=0;i<10;i++) {
				order.print3();
			}
		},"线程3");

		thread1.start();
		thread2.start();
		thread3.start();

	}
}

class Order{
	Lock lock=new ReentrantLock();
	Condition condition1=lock.newCondition();
	Condition condition2=lock.newCondition();
	Condition condition3=lock.newCondition();
	int number=1;
	public void print1() {
		lock.lock();
		try {
			while(number!=1) {
				condition1.await();
			}
			System.out.println(Thread.currentThread().getName()+"正在执行");
			number=2;
			condition2.signalAll();
		}catch(Exception e) {
			
		}finally {
			lock.unlock();
		}
		
	}
	public void print2() {
		lock.lock();
		try {
			while(number!=2) {
				condition2.await();
			}
			System.out.println(Thread.currentThread().getName()+"正在执行");
			number=3;
			condition3.signalAll();
		}catch(Exception e) {
			
		}finally {
			lock.unlock();
		}
		
	}
	public void print3() {
		lock.lock();
		try {
			while(number!=3) {
				condition3.await();
			}
			System.out.println(Thread.currentThread().getName()+"正在执行");
			number=1;
			condition1.signalAll();
		}catch(Exception e) {
			
		}finally {
			lock.unlock();
		}
		
	}
}

执行结果：