启动三个线程：AA、BB、CC

    • AA打印5次，BB打印5次，CC打印5次
    • 重复10轮

    解决方案：指定标识
    image.png

    1. class ThreadResource{
    2.     private int flag=1;//AA:1 BB:2 CC:3
    3.     private Lock lock=new ReentrantLock();
    4.     //为什么要创建三个condition？上一个例子是创建一个condition，唤醒所有的线程
    5.     //这里创建三个condition,通知下一个要执行的线程的condition
    6.     private Condition c1=lock.newCondition();
    7.     private Condition c2=lock.newCondition();
    8.     private Condition c3=lock.newCondition();
    10.     public void print5(int loop) throws InterruptedException {
    11.         //上锁
    12.         lock.lock();
    13.         try {
    14.             while(flag!=1){
    15.                 c1.await();//等待
    16.             }
    17.             for(int i=1;i<=5;i++){
    18.                 System.out.println(Thread.currentThread().getName()+"::"+i+"第"+loop+"轮");
    19.             }
    20.             flag=2;//修改标志位
    21.             c2.signal();//通知BB线程
    22.         }finally {
    23.             lock.unlock();
    24.         }
    25.     }
    27.     public void print10(int loop) throws InterruptedException {
    28.         //上锁
    29.         lock.lock();
    30.         try {
    31.             while(flag!=2){
    32.                 c2.await();//等待
    33.             }
    34.             for(int i=1;i<=10;i++){
    35.                 System.out.println(Thread.currentThread().getName()+"::"+i+"第"+loop+"轮");
    36.             }
    37.             flag=3;//修改标志位
    38.             c3.signal();//通知CC线程
    39.         }finally {
    40.             lock.unlock();
    41.         }
    42.     }
    44.     public void print15(int loop) throws InterruptedException {
    45.         //上锁
    46.         lock.lock();
    47.         try {
    48.             while(flag!=3){
    49.                 c3.await();//等待
    50.             }
    51.             for(int i=1;i<=15;i++){
    52.                 System.out.println(Thread.currentThread().getName()+"::"+i+"第"+loop+"轮");
    53.             }
    54.             flag=1;//修改标志位
    55.             c1.signal();//通知BB线程
    56.         }finally {
    57.             lock.unlock();
    58.         }
    59.     }
    60. }
    62. public class ThreadDemo {
    63.     public static void main(String[] args) {
    64.         ThreadResource threadResource = new ThreadResource();
    66.         new Thread(()->{
    67.             for(int i=1;i<=10;i++){
    68.                 try {
    69.                     threadResource.print5(i);
    70.                 } catch (InterruptedException e) {
    71.                     e.printStackTrace();
    72.                 }
    73.             }
    74.         },"AA").start();
    76.         new Thread(()->{
    77.             for(int i=1;i<=10;i++){
    78.                 try {
    79.                     threadResource.print10(i);
    80.                 } catch (InterruptedException e) {
    81.                     e.printStackTrace();
    82.                 }
    83.             }
    84.         },"BB").start();
    86.         new Thread(()->{
    87.             for(int i=1;i<=10;i++){
    88.                 try {
    89.                     threadResource.print15(i);
    90.                 } catch (InterruptedException e) {
    91.                     e.printStackTrace();
    92.                 }
    93.             }
    94.         },"CC").start();
    95.     }
    96. }