java 中多線程生產(chǎn)者消費(fèi)者問題詳細(xì)介紹

import java.util.concurrent.locks.*;

class BoundedBuffer {
  final Lock lock = new ReentrantLock();//對(duì)象鎖
  final Condition notFull = lock.newCondition(); //生產(chǎn)者監(jiān)視器
  final Condition notEmpty = lock.newCondition(); //消費(fèi)者監(jiān)視器

  //資源對(duì)象
  final Object[] items = new Object[10];
  //putptr生產(chǎn)者角標(biāo)，takeptr消費(fèi)者角標(biāo)，count計(jì)數(shù)器(容器的實(shí)際長(zhǎng)度)
  int putptr, takeptr, count;

  public void put(Object x) throws InterruptedException {
    //生產(chǎn)者拿到鎖
   lock.lock();
   try {
     //當(dāng)實(shí)際長(zhǎng)度不滿足容器的長(zhǎng)度
    while (count == items.length) 
      //生產(chǎn)者等待
     notFull.await();
    //把生產(chǎn)者產(chǎn)生對(duì)象加入容器
    items[putptr] = x; 
    System.out.println(Thread.currentThread().getName()+"   put-----------"+count);
    Thread.sleep(1000);
    //如果容器的實(shí)際長(zhǎng)==容器的長(zhǎng)，生產(chǎn)者角標(biāo)置為0
    if (++putptr == items.length) putptr = 0;
    ++count;
    //喚醒消費(fèi)者
    notEmpty.signal();
   } finally {
     //釋放鎖
    lock.unlock();
   }
  }

  public Object take() throws InterruptedException {
   lock.lock();
   try {
    while (count == 0) 
      //消費(fèi)者等待
     notEmpty.await();
    Object x = items[takeptr]; 
    System.out.println(Thread.currentThread().getName()+"   get-----------"+count);
    Thread.sleep(1000);
    if (++takeptr == items.length) takeptr = 0;
    --count;
    //喚醒生產(chǎn)者
    notFull.signal();
    return x;
   } finally {
     //釋放鎖
    lock.unlock();
   }
  } 
 }

class Consu implements Runnable{
  BoundedBuffer bbuf;

  public Consu(BoundedBuffer bbuf) {
    super();
    this.bbuf = bbuf;
  }

  @Override
  public void run() {
    while(true){
    try {
      bbuf.take() ;
    } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    }
  }

}
class Produ implements Runnable{
  BoundedBuffer bbuf;
  int i=0;
  public Produ(BoundedBuffer bbuf) {
    super();
    this.bbuf = bbuf;
  }

  @Override
  public void run() {
    while(true){
      try {
        bbuf.put(new String(""+i++)) ;
      } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    }
  }

}



//主方法
class Lock1{
  public static void main(String[] args) {
    BoundedBuffer bbuf=new BoundedBuffer();
    Consu c=new Consu(bbuf);
    Produ p=new Produ(bbuf);
    Thread t1=new Thread(p);
    Thread t2=new Thread(c);
    t1.start();
    t2.start();
    Thread t3=new Thread(p);
    Thread t4=new Thread(c);
    t3.start();
    t4.start();
  }
}