Java实现线程按序交替执行的方法详解

package com.xiaoxuzhu;

/**
 * Description: 
 *
 * @author xiaoxuzhu
 * @version 1.0
 *
 * <pre>
 * 修改记录:
 * 修改后版本	        修改人		修改日期			修改内容
 * 2022/5/15.1	    xiaoxuzhu		2022/5/15		    Create
 * </pre>
 * @date 2022/5/15
 */
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * Description: 
 *
 * @author xiaoxuzhu
 * @version 1.0
 *
 * <pre>
 * 修改记录:
 * 修改后版本	        修改人		修改日期			修改内容
 * 2022/5/15.1	    xiaoxuzhu		2022/5/15		    Create
 * </pre>
 * @date 2022/5/15
 */
public class AbcAlternateDemo1 {

    public static void main(String[] args) {
        Alternate alternate = new Alternate();
        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i < 10; i++) {
                    alternate.loopA(i);
                }
            }
        },"A").start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i < 10; i++) {
                    alternate.loopB(i);
                }
            }
        },"B").start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i < 10; i++) {
                    alternate.loopC(i);
                }
            }
        },"C").start();
    }

    static class Alternate{

        /**
         * //线程启动的顺序标识
         **/
        private int flag = 1;

        private Lock lock = new ReentrantLock();

        private Condition conditionA = lock.newCondition();
        private Condition conditionB = lock.newCondition();
        private Condition conditionC = lock.newCondition();

        public void loopA(int loopNum){
            lock.lock();
            try {
                if(flag !=1){
                    conditionA.await();
                }
                for (int i = 1; i <= 1; i++) {
                    System.out.println(Thread.currentThread().getName()+":"+"--"+loopNum+"--"+ i);
                }
                flag =2;
                conditionB.signalAll();
            }catch (Exception e){
                e.printStackTrace();
            }finally {
                lock.unlock();
            }
        }

        public void loopB(int loopNum){
            lock.lock();
            try {
                if(flag !=2){
                    conditionB.await();
                }
                for (int i = 1; i <= 1; i++) {
                    System.out.println(Thread.currentThread().getName()+":"+"--"+loopNum+"--"+ i);
                }
                flag =3;
                conditionC.signalAll();
            }catch (Exception e){
                e.printStackTrace();
            }finally {
                lock.unlock();
            }
        }

        public void loopC(int loopNum){
            lock.lock();
            try {
                if(flag !=3){
                    conditionC.await();
                }
                for (int i = 1; i <= 1; i++) {
                    System.out.println(Thread.currentThread().getName()+":"+"--"+loopNum+"--"+ i);
                }
                flag =1;
                System.out.println("----------------------");
                conditionA.signalAll();
            }catch (Exception e){
                e.printStackTrace();
            }finally {
                lock.unlock();
            }
        }

    }
}