生产者消费者问题 - 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;
/*
* @jdk5.0以后的版本中，用lock()等方法替换了synchronized,用condition替换了wait，notify，notifyAll。
* @同样的生产者消费者问题。
*/
class Resource2// 资源
{
private String name;
private int Count = 1;
private Boolean flag = false;
private Lock lock = new ReentrantLock();
private Condition condition_con = lock.newCondition();//消费者对象
private Condition condition_pro = lock.newCondition();//生产者对象
public void set(String name) throws InterruptedException// await未抛出异常(生产者)
{
lock.lock();
// if(flag)//将if替换为while可以避免多个线程生产消费的安全问题
try {
while (flag)
condition_pro.await();// await要抛出异常，因为没有写catch所有throw一下
this.name = name + "-------" + Count++;
System.out.println(Thread.currentThread().getName() + "---生产者"
+ this.name);
condition_con.signal();//消费者唤醒
flag = true;
} finally {
lock.unlock();
}
}
public void out() throws InterruptedException //消费者
{
lock.lock();
try {
// if(!flag)//将if替换为while可以避免多个线程生产消费的安全问题
while (!flag)
condition_con.await();
System.out.println(Thread.currentThread().getName()
+ "----------消费者" + this.name);
flag = false;
condition_pro.signal();//生产者唤醒
} finally {
lock.unlock();
}
}
}
class producer2 implements Runnable {
private Resource2 r;
producer2(Resource2 r) {
this.r = r;
}
public void run() {
while (true) {
try {
r.set("商品");
} catch (InterruptedException e) {
}
}
}
}
class Consumer2 implements Runnable {
private Resource2 r;
Consumer2(Resource2 r) {
this.r = r;
}
public void run() {
while (true) {
try {
r.out();
} catch (InterruptedException e) {
}
}
}
}
public class ProducerConsumerDemo2 {
public static void main(String[] args) {
Resource2 r = new Resource2();
producer2 pro = new producer2(r);
Consumer2 con = new Consumer2(r);
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();
}
}

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