进程通信

1. Object.wait方法（休眠）
   

2. Object.notifyAll和notify（唤醒）
   

3. 生产者与消费者

public class Demo12 {public static void main(String[] args) {//多线程通信    生产者与消费者问题Food f = new Food();new Cook(f).start();new Waiter(f).start();}//厨师static class Cook extends Thread{private Food f;public Cook(Food f) {this.f = f;}@Overridepublic void run() {for (int i = 0; i < 100; i++) {if(i%2==0){f.setNameAndTaste("老干妈小米粥","香辣味");}else {f.setNameAndTaste("煎饼果子","甜辣味");}}}}//服务员static class Waiter extends Thread{private Food f;public Waiter(Food f) {this.f = f;}@Overridepublic void run() {for (int i = 0; i < 100; i++) {try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}f.get();}}}//食物static class Food{private String name;private String taste;//true表示可以生产boolean flag = true;public synchronized void setNameAndTaste(String name,String taste){if(flag){this.name = name;try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}this.taste = taste;flag = false;this.notifyAll();try {this.wait();} catch (InterruptedException e) {e.printStackTrace();}}}public synchronized void get(){if(!flag){System.out.println("服务员端走的菜的名称是："+name+",味道是："+taste);flag = true;this.notifyAll();try {this.wait();} catch (InterruptedException e) {e.printStackTrace();}}}}
}

• 注意如果加上非公平锁，很可能陷入一个进程独自执行的情况。所以只加线程安全不能解决该问题。