多线程面试题之【三线程按顺序交替打印ABC的方法】多线程面试题之【三线程按顺

建立三个线程,线程名字分别为:A、B、C，要求三个线程分别打印自己的线程名字,但是要求三个线程同时运行，并且实现交替打印，即按照ABCABCABC的顺序打印。打印10轮，打印完毕控制台输出字符串:"打印完毕"
方法之一:使用Condition等待唤醒机制,代码如下：

import java.util.concurrent.CountDownLatch; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; /** * Created by gan on 2019/5/19 10:54. */ public class ConditionDemo {private static int num = 1; //打印“谁”标识符private static Lock lock = new ReentrantLock(); private static final Condition conditionA = lock.newCondition(); private static final Condition conditionB = lock.newCondition(); private static final Condition conditionC = lock.newCondition(); private static CountDownLatch countDownLatch = new CountDownLatch(10); //使用闭锁计数器public static void main(String[] args) throws Exception {long loop = countDownLatch.getCount(); //初始化打印轮数new Thread(() -> { for (int i = 1; i <= loop; i++) { try { printA(); } catch (InterruptedException e) { } } }, "A").start(); new Thread(() -> { for (int i = 1; i <= loop; i++) { try { printB(); } catch (InterruptedException e) { } } }, "B").start(); new Thread(() -> { for (int i = 1; i <= loop; i++) { try { printC(i); } catch (InterruptedException e) { } } }, "C").start(); countDownLatch.await(); System.out.println("打印完毕........."); }//打印‘A’的方法 public static void printA() throws InterruptedException { lock.lock(); if (num != 1) { //标识符等于1的时候打印A conditionA.await(); } System.out.print(Thread.currentThread().getName()); num = 2; conditionB.signal(); lock.unlock(); }//打印‘B’的方法 public static void printB() throws InterruptedException { lock.lock(); if (num != 2) { //标识符等于2的时候打印B conditionB.await(); } System.out.print(Thread.currentThread().getName()); num = 3; conditionC.signal(); lock.unlock(); }//打印‘C’的方法 public static void printC(int loop) throws InterruptedException { lock.lock(); if (num != 3) { //标识符等于3的时候打印A conditionC.await(); } System.out.print(Thread.currentThread().getName()); System.out.print("[" + loop + "]"); //轮数间隔符号 num = 1; conditionA.signal(); countDownLatch.countDown(); lock.unlock(); }}

运行结果如下:

【多线程面试题之【三线程按顺序交替打印ABC的方法】】转载于:https://www.cnblogs.com/ganbo/p/10889758.html