线程按序交替

线程按序交替

package com.yanxizhu;

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

/**
 * @description: 线程按序交替
 * @date: 2022/3/19 14:47
 * @version: 1.0
 */
public class PrintInfo {
    public static void main(String[] args) {
        print print = new print();
        new Thread(new Runnable() {
            @Override
            public void run() {
                for(int i=1;i<5;i++){
                    try {
                        print.printA(i);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        },"A").start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for(int i=1;i<5;i++){
                    try {
                        print.printB(i);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        },"B").start();


        new Thread(new Runnable() {
            @Override
            public void run() {
                for(int i=1;i<5;i++){
                    try {
                        print.printC(i);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        },"C").start();
    }
}
class print{

    private int num =1;
    Lock lock = new ReentrantLock();
    Condition condition1 = lock.newCondition();
    Condition condition2 = lock.newCondition();
    Condition condition3 = lock.newCondition();

    public void printA(int i) throws InterruptedException {
        lock.lock();
        try{
            if(num != 1){
                condition1.await();
            }
            System.out.println("A=="+Thread.currentThread().getName()+"====i="+i);

            num=2;
            condition2.signal();
        }finally {
            lock.unlock();
        }
    }

    public void printB(int i) throws InterruptedException {
        lock.lock();
        try{
            if(num != 2){
                condition2.await();
            }
            System.out.println("B=="+Thread.currentThread().getName()+"====i="+i);
            num=3;
            condition3.signal();
        }finally {
            lock.unlock();
        }
    }


    public void printC(int i) throws InterruptedException {
        lock.lock();
        try{
            if(num != 3){
                condition3.await();
            }
            System.out.println("C=="+Thread.currentThread().getName()+"====i="+i);
            num=1;
            condition1.signal();
        }finally {
            lock.unlock();
        }
    }
 }

打印结果：

A==A====i=1
B==B====i=1
C==C====i=1
A==A====i=2
B==B====i=2
C==C====i=2
A==A====i=3
B==B====i=3
C==C====i=3
A==A====i=4
B==B====i=4
C==C====i=4