三线程接力：有ABC三个线程，要求A打印5次，接着B打印10次，接着C打印15次，来10轮

痛定思痛。 2022-12-17 08:39 37阅读 0赞

## 线程类（只负责调用资源类，并启动线程，不负责锁） ##

import java.util.concurrent.Callable;
    import java.util.concurrent.FutureTask;
    import java.util.concurrent.locks.Condition;
    import java.util.concurrent.locks.Lock;
    import java.util.concurrent.locks.ReentrantLock;
    
    //A、B、C三个线程接力
    public class ThreadDemo05 {
        public static void main(String[] args) {
            final ShareResource sr = new ShareResource();
            
            FutureTask ft = new FutureTask(new Callable() {
                @Override
                public Object call() throws Exception {
                    for (int i = 1; i <= 10; i++) {
                        sr.printA(i);
                    }
                    return null;
                }
            });
            new Thread(ft, "aa").start();
            
            FutureTask ft2 = new FutureTask(new Callable() {
                @Override
                public Object call() throws Exception {
    
                    for (int i = 1; i <= 10; i++) {
                        sr.printB(i);
    
                    }
                    return null;
                }
            });
            new Thread(ft2, "bb").start();
            
            FutureTask ft3 = new FutureTask(new Callable() {
                @Override
                public Object call() throws Exception {
    
                    for (int i = 1; i <= 10; i++) {
                        sr.printC(i);
                    }
    
                    return null;
                }
            });
            new Thread(ft3, "cc").start();
        }
    }

## 资源类：（锁是在资源类中） ##

class ShareResource {
        private int flag = 1; // 1->A,2-B,3-C
        private Lock lock = new ReentrantLock();
        private Condition c1 = lock.newCondition();  //只有一个是不行的
        private Condition c2 = lock.newCondition();
        private Condition c3 = lock.newCondition();
    
        public void printA(int totalLoop) {
            lock.lock();
            try {
                // 1.判断
                while (flag != 1) {
                    c1.await();
                }
                // 2.干活
                for (int i = 1; i <= 5; i++) {
                    System.out.println(Thread.currentThread().getName() + "--" + i + "轮数：" + totalLoop);
                }
                // 3.通知唤醒
                flag = 2;
                c2.signal();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    
        public void printB(int totalLoop) {
            lock.lock();
            try {
                while (flag != 2) {
                    c2.await();
                }
                for (int i = 1; i <= 10; i++) {
                    System.out.println(Thread.currentThread().getName() + "--" + i + "轮数：" + totalLoop);
                }
                flag = 3;
                c3.signal();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    
        public void printC(int totalLoop) {
            lock.lock();
            try {
                while (flag != 3) {
                    c3.await();
                }
                for (int i = 1; i <= 10; i++) {
                    System.out.println(Thread.currentThread().getName() + "--" + i + "轮数：" + totalLoop);
                }
                flag = 1;
                c1.signal();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    }