[javaSE] 多线程通信（等待-唤醒机制）

两个线程操作同一个资源，比如，输入和输出，操作同一个对象，此时两个线程会争夺cpu的执行权，随机的进行切换。我们想实现先输入再输出，顺序的执行

 

目标对象定义一个标记字段，进行判断，wait()和notify()方法

wait()方法，线程会处于等待状态，等待的线程位于内存中的线程池中

notify()方法，唤醒线程池中的线程

notifyAll()方法，唤醒全部线程

上面的方法，需要写在同步里面，并且需要标识锁

这些操作线程的方法定义在Object对象中，因为这些方法，要通过同一个锁对象来调用

 

 

/**
 * 资源
 * 
 * @author taoshihan
 * 
 */
class People {
    String name;
    String sex;
    Boolean myLock = false;
}

/**
 * 输入
 * 
 * @author taoshihan
 * 
 */
class PeopleJoin implements Runnable {
    private People resource;

    public PeopleJoin(People resource) {
        this.resource = resource;
    }

    @Override
    public void run() {
        // 切换
        boolean flag = true;
        while (true) {
            synchronized (resource) {
                if (resource.myLock) {
                    try {
                        resource.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                if (flag) {
                    resource.name = "taoshihan";
                    resource.sex = "nan";
                } else {
                    resource.name = "陶士涵";
                    resource.sex = "男";
                }
                flag = !flag;
                resource.myLock=true;
                resource.notify();
            }
        }
    }

}

/**
 * 输出
 * 
 * @author taoshihan
 * 
 */
class PeopleOut implements Runnable {
    private People resource;

    public PeopleOut(People resource) {
        this.resource = resource;
    }

    @Override
    public void run() {
        while (true) {
            synchronized (resource) {
                if(!resource.myLock){
                    try {
                        resource.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                System.out.println(resource.name + "=====" + resource.sex);
                resource.myLock=false;
                resource.notify();
            }
        }
    }

}

public class ThreadDemo {

    /**
     * @param args
     */
    public static void main(String[] args) {
        People resource = new People();
        PeopleJoin input = new PeopleJoin(resource);
        PeopleOut output = new PeopleOut(resource);

        Thread t1 = new Thread(input);
        Thread t2 = new Thread(output);
        t1.start();
        t2.start();
    }

}