Notifyall学习笔记

在同步代码块中,用哪个对象锁,就用哪个对象调用wait方法

• 2,为什么wait方法和notify方法定义在Object这类中?

• 因为锁对象可以是任意对象,Object是所有的类的基类,所以wait方法和notify方法需要定义在Object这个类中

• 3,sleep方法和wait方法的区别?

• a,sleep方法必须传入参数,参数就是时间,时间到了自动醒来

• wait方法可以传入参数也可以不传入参数,传入参数就是在参数的时间结束后等待,不传入参数就是直接等待

• b,sleep方法在同步函数或同步代码块中,不释放锁,睡着了也抱着锁睡

• wait方法在同步函数或者同步代码块中,释放锁

/**     * @param args     */    public static void main(String[] args) {        final Printer2 p = new Printer2();        new Thread() {            public void run() {                while(true) {                    try {                        p.print1();                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }            }        }.start();        new Thread() {            public void run() {                while(true) {                    try {                        p.print2();                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }            }        }.start();        new Thread() {            public void run() {                while(true) {                    try {                        p.print3();                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }            }        }.start();    }}/*1,在同步代码块中,用哪个对象锁,就用哪个对象调用wait方法 * 2,为什么wait方法和notify方法定义在Object这类中? *  因为锁对象可以是任意对象,Object是所有的类的基类,所以wait方法和notify方法需要定义在Object这个类中 * 3,sleep方法和wait方法的区别? * a,sleep方法必须传入参数,参数就是时间,时间到了自动醒来 *   wait方法可以传入参数也可以不传入参数,传入参数就是在参数的时间结束后等待,不传入参数就是直接等待 * b,sleep方法在同步函数或同步代码块中,不释放锁,睡着了也抱着锁睡 *  wait方法在同步函数或者同步代码块中,释放锁 */ class Printer2 {    private int flag = 1;    public void print1() throws InterruptedException {                                  synchronized(this) {            while(flag != 1) {                this.wait();                    //当前线程等待            }            System.out.print("黑");            System.out.print("马");            System.out.print("程");            System.out.print("序");            System.out.print("员");            System.out.print("\r\n");            flag = 2;            //this.notify();                        //随机唤醒单个等待的线程            this.notifyAll();        }    }    public void print2() throws InterruptedException {        synchronized(this) {            while(flag != 2) {                this.wait();                    //线程2在此等待            }            System.out.print("传");            System.out.print("智");            System.out.print("播");            System.out.print("客");            System.out.print("\r\n");            flag = 3;            //this.notify();            this.notifyAll();        }    }    public void print3() throws InterruptedException {        synchronized(this) {            while(flag != 3) {                this.wait();                        //线程3在此等待,if语句是在哪里等待,就在哪里起来                                                    //while循环是循环判断,每次都会判断标记            }            System.out.print("i");            System.out.print("t");            System.out.print("h");            System.out.print("e");            System.out.print("i");            System.out.print("m");            System.out.print("a");            System.out.print("\r\n");            flag = 1;            //this.notify();            this.notifyAll();        }    }