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java多线程 生产者消费者问题

2011-06-11 22:02 337 查看
java多线程 消费者-生产者 收藏
java多线程一般都会讲消费者-生产者模型
生产者与消费者模型中,要保证以下几点:
1 同一时间内只能有一个生产者生产
2 同一时间内只能有一个消费者消费
3 生产者生产的同时消费者不能消费
4 消息队列满时生产者不能继续生产
5 消息队列空时消费者不能继续消费
参考了下网上一个代码实例http://www.talented.com.cn/archives/2007/5/16_141.html  发现作者写得有问题 修改了一些代码  现在ok了
----------------------------------------------------Message类
package com.example.test;
public class Message {

public static int id;
public String content;
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public int getId() {
return id;
}
public void setId(int id) {
Message.id = id;
}
}
----------------------------------------------------Queue类
package com.example.test;
import java.util.ArrayList;
import java.util.List;
public class Queue {
List<Message> queue = new ArrayList<Message>();
/** 队列中message对象的最大值,默认为5 */
int maxMessageNum = 5;
public synchronized void produce(Message message) {
this.notifyAll();
while (queue.size() == maxMessageNum) {
System.out.println(Thread.currentThread().getName()
+ "  队列满!等待中。。。");
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
queue.add(message);
System.out.println(Thread.currentThread().getName() + "正在生产"
+ message.getContent() + "。。。  ,当前个数:" + getCount());
}
public synchronized void consume() {
this.notifyAll();
while (queue.size() == 0) {
System.out.println(Thread.currentThread().getName()
+ "  队列空!等待中。。。");
try {
System.out.println("begin!");
wait();
System.out.println("end!");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
Message message = queue.get(0);
queue.remove(0);
System.out.println(Thread.currentThread().getName() + "正在消费"
+ message.getContent() + "。。。 ,当前个数: " + getCount());
}
public synchronized int getCount() {
return queue.size();
}
}

----------------------------------------------------Test类
package com.example.test;
public class Test {
public static void main(String[] args) {
Queue Q = new Queue();
Producer wQ1 = new Producer(Q);
Producer wQ2 = new Producer(Q);

Consumer rQ1 = new Consumer(Q);
Consumer rQ2 = new Consumer(Q);
Consumer rQ3 = new Consumer(Q);

Thread threadWQ1 = new Thread(wQ1, "thread-wQ1");
Thread threadWQ2 = new Thread(wQ2, "thread-wQ2");
Thread threadRQ1 = new Thread(rQ1, "thread-rQ1");
Thread threadRQ2 = new Thread(rQ2, "thread-rQ2");
Thread threadRQ3 = new Thread(rQ3, "thread-rQ3");

threadWQ1.start();
threadWQ2.start();

threadRQ1.start();
threadRQ2.start();
threadRQ3.start();
}
}
class Producer extends Thread {
private Queue queue;
Producer(Queue queue) {
this.queue = queue;
}
public void run() {

while (true) {
Message message = new Message();
message.setId(++Message.id);
message.setContent("food"+Message.id);
queue.produce(message);
try {
sleep(100);
} catch (Exception e) {
}
}
}
}
class Consumer extends Thread {
private Queue queue;
Consumer(Queue queue) {
this.queue = queue;
}
public void run() {
while (true) {
queue.consume();
try {
sleep(100);
} catch (Exception e) {
}
}
}
}
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