代码如下:
class Test
{
public static void main(String[] args)
{
Queue q=new Queue();
Producer p=new Producer(q);
Consumer c=new Consumer(q);
p.start();
c.start();
}
}class Producer extends Thread
{
Queue q;
Producer(Queue q)
{
this.q=q;
}
public void run()
{
for(int i=0;i<100;i++)
{
q.put(i);//这里时间片用完了?
System.out.println("Producer put "+i);
}
}
}
class Consumer extends Thread
{
Queue q;
Consumer(Queue q)
{
this.q=q;
}
public void run()
{
while(true)
{
System.out.println("Consumer get "+q.get());
}
}
}
class Queue
{
int value;
boolean bFull=false;
public synchronized void put(int i)
{
if(!bFull)
{
value=i;
bFull=true;
notify();
}
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
public synchronized int get()
{
if(!bFull)
{
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
bFull=false;
notify();
return value;
}
}执行结果:
Producer put 0
Consumer get 0
Producer put 1
Consumer get 1
Producer put 2
Consumer get 2
Producer put 3
Consumer get 3
Producer put 4
Consumer get 4
Producer put 5
Consumer get 5
Producer put 6
Consumer get 6
Producer put 7
Consumer get 7
Consumer get 8
这里怎么还没有put8就get8了啊!是不是执行到标记处之间片用完了?
Producer put 8
Consumer get 9
Producer put 9
Consumer get 10
Producer put 10
Consumer get 11
Producer put 11
Consumer get 12
class Test
{
public static void main(String[] args)
{
Queue q=new Queue();
Producer p=new Producer(q);
Consumer c=new Consumer(q);
p.start();
c.start();
}
}class Producer extends Thread
{
Queue q;
Producer(Queue q)
{
this.q=q;
}
public void run()
{
for(int i=0;i<100;i++)
{
q.put(i);//这里时间片用完了?
System.out.println("Producer put "+i);
}
}
}
class Consumer extends Thread
{
Queue q;
Consumer(Queue q)
{
this.q=q;
}
public void run()
{
while(true)
{
System.out.println("Consumer get "+q.get());
}
}
}
class Queue
{
int value;
boolean bFull=false;
public synchronized void put(int i)
{
if(!bFull)
{
value=i;
bFull=true;
notify();
}
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
public synchronized int get()
{
if(!bFull)
{
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
bFull=false;
notify();
return value;
}
}执行结果:
Producer put 0
Consumer get 0
Producer put 1
Consumer get 1
Producer put 2
Consumer get 2
Producer put 3
Consumer get 3
Producer put 4
Consumer get 4
Producer put 5
Consumer get 5
Producer put 6
Consumer get 6
Producer put 7
Consumer get 7
Consumer get 8
这里怎么还没有put8就get8了啊!是不是执行到标记处之间片用完了?
Producer put 8
Consumer get 9
Producer put 9
Consumer get 10
Producer put 10
Consumer get 11
Producer put 11
Consumer get 12
{
public static void main(String[] args)
{
Producer j=producer();
Thread t=new Thread(j);
t.setDaemon(true);
t.start();
consumer a=consumer();
Thread b=new Thread(a);
t.setDaemon(true);
b.start(); }
}class Producer implements Runnable
{
Queue q=null;
Producer(Queue q)
{
this.q=q;
}
public void run()
{
for(int i=0;i<100;i++)
{
q.put(i);//这里时间片用完了?
System.out.println("Producer put "+i);
}
}
}
class Consumer implements Thread
{
Queue q;
Consumer(Queue q)
{
this.q=q;
}
public void run()
{
while(true)
{
System.out.println("Consumer get "+q.get());
}
}
}
class Queue implements Runnable
{
int value;
boolean bFull=false;
public synchronized void put(int i)
{
if(!bFull)
{
wait();
this.value=i;
try{
Thread.sleep(10);
}
catch(Exception)
{
System.out.println(e.getMessage); }
bFull=true;
notify();
}
}
}
public synchronized int get()
{
if(!bFull)
wait();
bFull=false;
notify();
return value;
}
}
写的啥子程序,线程怎么写的呀 我晕!!什么EXTENDS都来了 你那叫什么东西
写:你写的程序逻辑上没问题,但是请考虑:Producer的run方法内部
for(int i=0;i<100;i++)
{
q.put(i);
System.out.println("Producer put "+i);
}
和Consumer的run方法内部
while(true)
{
System.out.println("Consumer get "+q.get());
}
在线程切换的时候可以有4种切换方式!因为你只是把对象q加锁,所以q.put(i)和q.get()是原语,但是q.put(i)和System.out.println("Producer put "+i)不是原语。有可能q.put(i)刚返回的时候,时间片到时,切换到q.get()但是没有输出 Producer put i ;等到System.out.println("Consumer get "+q.get());执行完成时再切换回原来状态,这时输出才Producer put i;所以会有执行结果:消费者先取,生产者再放的假像,即Consumer get 8 ; Producer put 8;改正方法:使System.out.println("Consumer get "+q.get());和q.put(i);
System.out.println("Producer put "+i);成为原语;办法2种;
1:把 System.out.println("Producer put "+i);放到put()方法内部)
class Queue
{
int value;
boolean bFull = false;
public synchronized void put(int i)
{
if(!bFull)
{
value=i;
System.out.println("Producer put "+i);
bFull=true;
notify();
}
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
public synchronized int get()
{
if(!bFull)
{
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
bFull = false;
System.out.println("Consumer get " + value);
notify();
return value;
}
}class Producer extends Thread
{
Queue q;
Producer(Queue q)
{
this.q = q;
}
public void run()
{
for(int i = 0 ; i < 10000 ; i++)
{
q.put(i);
}
}
}class Consumer extends Thread
{
Queue q;
Consumer(Queue q)
{
this.q=q;
}
public void run()
{
while(true)
{
q.get();
}
}
}class Test
{
public static void main(String[] args)
{
Queue q=new Queue();
Producer p=new Producer(q);
Consumer c=new Consumer(q);
p.start();
c.start();
}
}
把2个run()内的循环语句段加锁,使之成为原语,具体见下面代码class Producer extends Thread
{
Queue q;
Producer(Queue q)
{
this.q=q;
}
public void run()
{
synchronized(q)
{
for(int i=0;i<100;i++)
{
System.out.println("Producer put "+i);
q.put(i);
}
}
}
}
class Consumer extends Thread
{
Queue q;
Consumer(Queue q)
{
this.q=q;
}
public void run()
{
synchronized(q)
{
while(true)
{
System.out.println("Consumer get " + q.get());
}
}
}
}
class Queue
{
int value;
boolean bFull=false;
public void put(int i)
{
if(!bFull)
{
value=i;
bFull=true;
notify();
}
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
public int get()
{
if(!bFull)
{
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
bFull=false;
notify();
return value;
}
}class Test
{
public static void main(String[] args)
{
Queue q=new Queue();
Producer p=new Producer(q);
Consumer c=new Consumer(q);
p.start();
c.start();
}
}
多谢,我是新手刚学的java!请过来人多指教!