简单的线程同步

同步方案

A执行完通知B，B执行完通知C，C执行完通知A

代码

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

public class ThreadTest {
    public static void main(String[] args) {
        ThreadTask threadTask = new ThreadTask();
        new Thread(()->{ for(int i = 0; i < 10; ++i){ threadTask.printA(); } },
                "A").start();
        new Thread(()->{ for(int i = 0; i < 10; ++i){ threadTask.printB(); } },
                "B").start();
        new Thread(()->{ for(int i = 0; i < 10; ++i){ threadTask.printC(); } },
                "C").start();
    }
}

class ThreadTask{
    private Lock lock = new ReentrantLock();
    private Condition conditionA = lock.newCondition();
    private Condition conditionB = lock.newCondition();
    private Condition conditionC = lock.newCondition();
    private int number = 1; //1A 2B 3C

    public void printA(){
        lock.lock();
        try {
            while(number != 1){
                conditionA.await();
            }
            System.out.println(Thread.currentThread().getName() + "---->A");
            number = 2;
            conditionB.signal();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }

    public void printB(){
        lock.lock();
        try {
            while (number != 2){
                conditionB.await();
            }
            System.out.println(Thread.currentThread().getName() + "---->B");
            number = 3;
            conditionC.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }

    public void printC(){
        lock.lock();
        try {
            while (number != 3){
                conditionC.await();
            }
            System.out.println(Thread.currentThread().getName() + "---->C");
            number = 1;
            conditionA.signal();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
}