线程问题 - 黑马程序员技术交流社区

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
//请问下面的代码为什么只有2个线程在打印其它线程怎么都停在那里不输出了呢
public class ProducerConsumerDemo2 {
public static void main(String[] args) {
Resource r = new Resource();
Producer pro = new Producer(r);
Consumer con = new Consumer(r);
//只测试t1、t2构成的死锁。也可以同时测t3、t4.
Thread t1 = new Thread(pro);
Thread t2 = new Thread(pro);
//Thread t3 = new Thread(con);
//Thread t4 = new Thread(con);
t1.start();
t2.start();
//t3.start();
// t4.start();
}
}
class Resource {
static int p=0;//此静态变量用于监视执行顺序。
private String name;
private int count = 1;
private boolean flag;
// 创建锁
Lock lock = new ReentrantLock();
// 通过锁对象创建2组监视器对象，分别用于监视生产者和消费者
Condition producer_con = lock.newCondition();
Condition consumer_con = lock.newCondition();
public synchronized void set(String name) {
lock.lock();
System.out.println(Thread.currentThread().getName() +"---set-上--"+Resource.p+++"---"+flag);//监视
try {
while (flag)
try {
System.out.println(Thread.currentThread().getName() +"---set---"+Resource.p+++"---"+flag);//监视
producer_con.await();
System.out.println(Thread.currentThread().getName() +"---set-await--"+Resource.p+++"---"+flag);//监视
} catch (InterruptedException e) {
}
this.name = name + (count++);
System.out.println(Thread.currentThread().getName() + "....生产"
+ this.name);
flag = true;
System.out.println(Thread.currentThread().getName() +"---set-下--"+Resource.p+++"---"+flag);//监视
consumer_con.signal();
} finally {
lock.unlock();
}
}
public synchronized void out() {
//System.out.println(Thread.currentThread().getName() +"---out()-上--"+Resource.p+++"---"+flag);
lock.lock();
try {
while (!flag)
try {
consumer_con.await();
} catch (InterruptedException e) {
}
System.out.println(Thread.currentThread().getName()
+ "*************消费" + this.name);
flag = false;
//System.out.println(Thread.currentThread().getName() +"---out()-下--"+Resource.p+++"---"+flag);
producer_con.signal();
} finally {
lock.unlock();
}
}
}
class Producer implements Runnable {
private Resource r;
Producer(Resource r) {
this.r = r;
}
public void run() {
while (true) {
System.out.println(Thread.currentThread().getName() +"--Producer-run()---"+Resource.p+++"---");//监视
r.set("商品");
}
}
}
class Consumer implements Runnable {
private Resource r;
Consumer(Resource r) {
this.r = r;
}
public void run() {
while (true) {
//System.out.println(Thread.currentThread().getName() +"--Consumer-run()---"+Resource.p+++"---");
r.out();
}
}
}

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