Android中对象锁

Android中对象锁的wait()和notify()

基本概念：对象锁synchronized（object）{….}用法
在以上的代码块中只能由一个线程执行！！！
wait()、notify()是用在这个代码块当中的。wait()可以使当前线程A马上失去对象锁并且沉睡，直到对象调用notify()唤醒该线程。此时持有对象锁的线程B会先行执行完毕，然后再将对象锁交给线程A继续执行。
例子说明：

public class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

首先创建一个供线程竞争的Person类，含有构造方法和get、set方法。

final Person person = new Person("王龙",23);
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (person){
                    try {
                        for (int i = 0 ; i<10 ; i++) {
                            Thread.sleep(1000);
                            Log.e(person.getName(),"观自在菩萨，行深般若波若蜜多时"+i);
                            if (i==5){
                                person.wait();
                            }
                        }
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        },"Thread1");
        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                synchronized (person){
                    try {
                        for ( int i = 0 ; i < 10 ; i++ ){
                            Thread.sleep(1000);
                            Log.e(person.getName(),"照见五蕴皆空，度一切苦厄"+i);
                            if (i==5){
                                person.notify();
                            }
                        }
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                }
            }
        },"Thread2");
        t1.start();
        t2.start();

线程A和线程B是并发执行的。线程A每隔1s打印一条日志。当循环到第5次的是否wait()放弃对象锁并沉睡。此时线程B获得对象锁开始执行。执行到第5次循环。notify()唤醒线程A。

执行结果:

01-13 15:45:18.335 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时0
01-13 15:45:19.335 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时1
01-13 15:45:20.335 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时2
01-13 15:45:21.335 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时3
01-13 15:45:22.335 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时4
01-13 15:45:23.335 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时5
01-13 15:45:24.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄0
01-13 15:45:25.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄1
01-13 15:45:26.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄2
01-13 15:45:27.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄3
01-13 15:45:28.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄4
01-13 15:45:29.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄5
01-13 15:45:30.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄6
01-13 15:45:31.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄7
01-13 15:45:32.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄8
01-13 15:45:33.335 15435-15907/com.huaxinzhi.usingthreadpool E/王龙: 照见五蕴皆空，度一切苦厄9
01-13 15:45:34.335 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时6
01-13 15:45:35.345 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时7
01-13 15:45:36.345 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时8
01-13 15:45:37.345 15435-15906/com.huaxinzhi.usingthreadpool E/王龙: 观自在菩萨，行深般若波若蜜多时9