Java多线程--三个线程分别打印a,b,c.请用多线程实现循环打印15次abc

扫盲:

想想自己多线程解决生产消费者问题就知道个synchronized,真是惭愧

为做此题目特意学习新的多线程知识–ReentrantLock跟synchronized一样都是Java中的可重入锁(可以在内部锁中拿到外部锁)

Condition是条件的意思,Condition.await()让线程进入等待,Condition.signal()唤醒线程

package cn.itchg;

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

/**
* Created by CHG on 2017-02-23 20:20.
*/
public class PrintABC {
int count = 0; //打印次数
Lock lock = new ReentrantLock();  //可重写锁
Condition conditionA = this.lock.newCondition();
Condition conditionB = this.lock.newCondition();
Condition conditionC = this.lock.newCondition();

public class PrintA implements Runnable {
@Override
public void run() {
while (true)
if (count < 15) {
lock.lock();
System.out.print("A");
try {
conditionB.signal();  //线程b唤醒,因为a打印完应该打印b
conditionA.await();  //线程a进入等待队列
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}

}
}
}

public class PrintB implements Runnable {
@Override
public void run() {
while (true)
if (count < 15) {
lock.lock();
System.out.print("B");
try {
conditionC.signal();
conditionB.await();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}

}
}
}

public class PrintC implements Runnable {
@Override
public void run() {
while (true)
if (count < 15) {
lock.lock();
System.out.println("C" + count);
count++;//打印完c后,count++
try {
conditionA.signal();
conditionC.await();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}

}
}
}

public static void main(String[] args) {
PrintABC printABCD = new PrintABC();
new Thread(printABCD.new PrintA()).start();
new Thread(printABCD.new PrintB()).start();
new Thread(printABCD.new PrintC()).start();

}

}

执行结果:

ABC0
ABC1
ABC2
ABC3
ABC4
ABC5
ABC6
ABC7
ABC8
ABC9
ABC10
ABC11
ABC12
ABC13
ABC14

Process finished with exit code 1