java -13等待唤醒机制

• 资源类

 public class Student {
     String name;
     int age;
     boolean flag; // 默认情况是没有数据，如果是true，说明有数据
 }

• 生产者

public class SetThread implements Runnable {

    private Student s;
    private int x = 0;

    public SetThread(Student s) {
        this.s = s;
    }

    @Override
    public void run() {
        while (true) {
            synchronized (s) {
                //判断有没有
                if(s.flag){
                    try {
                        s.wait(); //t1等着，释放锁
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                
                if (x % 2 == 0) {
                    s.name = "张三";
                    s.age = 23;
                } else {
                    s.name = "李四";
                    s.age = 24;
                }
                x++; //x=1
                
                //修改标记
                s.flag = true;
                //唤醒线程
                s.notify(); //唤醒t2,唤醒并不表示你立马可以执行，必须还得抢CPU的执行权。
            }
            //t1有，或者t2有
        }
    }
}

• 消费者

public class GetThread implements Runnable {
    private Student s;

    public GetThread(Student s) {
        this.s = s;
    }

    @Override
    public void run() {
        while (true) {
            synchronized (s) {
                if(!s.flag){
                    try {
                        s.wait(); //t2就等待了。立即释放锁。将来醒过来的时候，是从这里醒过来的时候
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                
                System.out.println(s.name + "---" + s.age);
                //张三---23
                //李四---24
                
                //修改标记
                s.flag = false;
                //唤醒线程
                s.notify(); //唤醒t1
            }
        }
    }
}

• 测试类

public class StudentDemo {
    public static void main(String[] args) {
        //创建资源
        Student s = new Student();
        
        //设置和获取的类
        SetThread st = new SetThread(s);
        GetThread gt = new GetThread(s);

        //线程类
        Thread t1 = new Thread(st);
        Thread t2 = new Thread(gt);

        //启动线程
        t1.start();
        t2.start();
    }
}