Condition和ReentrantLock使用_condition c = lock.newcondition();-优快云博客

本文链接：https://blog.youkuaiyun.com/cckkpp/article/details/88597924

本文详细介绍了一个使用Java实现的线程同步案例，通过ReentrantLock和Condition来控制三个线程A、B、C的交替执行，确保了线程安全并实现了ABCABCABC的有序打印。深入探讨了信号量和条件变量的运用。

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三个线程交替执行ABCABCABC
A线程打印A
B线程打印B
C线程打印C

package com.roocon.thread.ta9;

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

public class Demo {
	
	private int signal;
	
	Lock lock = new ReentrantLock();
	Condition a = lock.newCondition();
	Condition b = lock.newCondition();
	Condition c = lock.newCondition();
	
	
	public void a() {
		lock.lock();
		while(signal != 0 ) {
			try {
				a.await();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		System.out.println("a");
		signal ++;
		b.signal();
		lock.unlock();
	}
	
	public  void b() {
		lock.lock();
		while(signal != 1) {
			try {
				b.await();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		System.out.println("b");
		signal ++;
		c.signal();
		lock.unlock();
	}
	
	public  void c () {
		lock.lock();
		while(signal != 2) {
			try {
				c.await();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		System.out.println("c");
		signal = 0;
		a.signal();
		lock.unlock();
	}
	
	public static void main(String[] args) {
		
		Demo d = new Demo();
		A a = new A(d);
		B b = new B(d);
		C c = new C(d);
		
		new Thread(a).start();
		new Thread(b).start();
		new Thread(c).start();
		
	}
}

class A implements Runnable {
	
	private Demo demo;
	
	public A(Demo demo) {
		this.demo = demo;
	}

	@Override
	public void run() {
		while(true) {
			demo.a();
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	
}
class B implements Runnable {
	
	private Demo demo;
	
	public B(Demo demo) {
		this.demo = demo;
	}
	
	@Override
	public void run() {
		while(true) {
			demo.b();
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	
}
class C implements Runnable {
	
	private Demo demo;
	
	public C(Demo demo) {
		this.demo = demo;
	}
	
	@Override
	public void run() {
		while(true) {
			demo.c();
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	
}