多线程——用Lock（锁）和Condition（监听器）来优化生产者消费者模式（进一步优化，解决可能产生的死锁问题）

package com.qianfeng.demo02 ;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;/** * 之前解决本方唤醒对方的问题是唤醒了线程池中全部线程。 * 缺点：这样做可以实现，但是效率比较低，而且还唤醒了本方。 *  * 升级之后lock和condition就能解决这个问题。 * 之前是两个锁嵌套可能出现死锁的问题，现在的解决方案是只有一个锁，但是锁上面可以加入多个监视器。 * 一个用来监视生成者，一个用来监视消费者。 *  * *///资源class Resource{private String name;private int count = 1;private boolean flag;  //判断盘子里是否有馒头的标志位。//指定一把锁private Lock lock = new ReentrantLock();//获取锁的监视器private Condition pro_con = lock.newCondition();   //负责监视生产者private Condition cus_con = lock.newCondition();   //负责监视消费者public void set(String name){//获取锁lock.lock();try {while (flag) {try {pro_con.await();} catch (InterruptedException e) {e.printStackTrace();}}this.name = name+count;count++;System.out.println(Thread.currentThread().getName()+"....生产了..."+this.name);flag = true;cus_con.signal();} catch (Exception e) {e.printStackTrace();}finally {lock.unlock();    //释放锁}}public  void get(){lock.lock();try {while (!flag) {try {cus_con.await();} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}}System.out.println(Thread.currentThread().getName()+"....消费了..."+this.name);flag = false;pro_con.signal();} catch (Exception e) {// TODO: handle exception}finally {lock.unlock();}}}//生产者class Produce implements Runnable{private Resource  r;public Produce (Resource  r) {this.r = r;}@Overridepublic void run() {while (true) {r.set("馒头");}}}//消费者class Customer  implements Runnable{private Resource  r;public Customer (Resource  r) {this.r = r;}@Overridepublic void run() {while (true) {r.get();}}}public class LockDemo02  {public static void main(String[] args) {Resource  r = new Resource ();Produce  p = new Produce (r);Customer  c = new Customer (r);Thread t0 = new Thread(p);Thread t1 = new Thread(p);Thread t  = new Thread(c);Thread t3 = new Thread(c);t0.start();t1.start();t .start();t3.start();}}