java线程同步

这次写一个多线程的demo，用生活中的例子来讲,妈妈要做饭,打开冰箱一看,菜和米都没有了。于是让我去买菜,让爸爸去买米。我去买菜和爸爸去买米是并发执行的,互相不干涉。但是妈妈没有米和菜式没法做饭的,所以等着米和菜把饭做好。代码如下:

public class threadDemo {



    /**

     * @param args

     */

    private static Object lock = new Object();



    public static void main(String[] args) {

        // TODO Auto-generated method stub

        Thread t1 = new Thread(new Runnable() {



            @Override

            public void run() {

                synchronized (lock) {

                    System.out.println("妈妈去做饭,发现没有菜和米,让我去买菜,爸爸去买米");

                    try {

                        lock.wait();

                        lock.wait();

                    } catch (InterruptedException e) {

                        // TODO Auto-generated catch block

                        e.printStackTrace();

                    }

                    System.out.println("妈妈把做饭做好");

                }

            }

        });

        t1.start();

        Thread t2 = new Thread(new Runnable() {



            @Override

            public void run() {

                synchronized (lock) {

                    System.out.println("我去买菜...");

                    try {

                        Thread.sleep(2000);

                    } catch (InterruptedException e) {

                        // TODO Auto-generated catch block

                        e.printStackTrace();

                    }

                    System.out.println("把菜给妈妈");

                    lock.notify();

                }

            }

        });

        t2.start();

        Thread t3 = new Thread(new Runnable() {



            @Override

            public void run() {

                System.out.println("爸爸去买米...");

                synchronized (lock) {

                    try {

                        Thread.sleep(3000);

                    } catch (InterruptedException e) {

                        // TODO Auto-generated catch block

                        e.printStackTrace();

                    }

                    System.out.println("把米给妈妈");

                    lock.notify();

                }

            }

        });

        t3.start();

    }

    

}

效果:

妈妈去做饭,发现没有菜和米,让我去买菜,爸爸去买米

我去买菜...

爸爸去买米...

把菜给妈妈

把米给妈妈

妈妈把做饭做好