线程静态同步与非静态差别

那么，在static方法和非static方法前面加synchronized到底有什么不同呢？

大家都知道，static的方法属于类方法，它属于这个Class(注意：这里的Class不是指Class的某个具体对

象)，那么static获取到的锁，就是当前调用这个方法的对象所属的类(Class，而不再是由这个Class产生

的某个具体对象了)。而非static方法获取到的锁，就是当前调用这个方法的对象的锁了。所以他们之间不

会产生互斥。

package com.jack.zhang.chapter9.classlock;

/**
 *
 * @author EX-LIUQI001
 *
 */
public class Test {

	public static synchronized void staticX() throws InterruptedException {
		for (int i = 0; i < 10; i++) {
			Thread.sleep(1000);
			System.out.println("staticX.......................");
		}
	}

	public synchronized void x() throws InterruptedException {

		for (int i = 0; i < 10; i++) {
			Thread.sleep(1000);
			System.out.println("x.......................");
		}

	}

	public static void main(String[] args) {
		final Test test1 = new Test();
		Thread thread = new Thread(new Runnable() {
			public void run() {
				try {
					test1.x();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}, "a");

		Thread thread1 = new Thread(new Runnable() {
			public void run() {
				try {
					Test.staticX();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}, "b");
		thread1.start();
		thread.start();
	}
}

运行结果是：

staticX.......................

x.......................

x.......................

staticX.......................

staticX.......................

x.......................

x.......................

staticX.......................

x.......................

staticX.......................

staticX.......................

x.......................

x.......................

staticX.......................

x.......................

staticX.......................

x.......................

staticX.......................

x.......................

staticX.......................

那当我们想让所有这个类下面的对象都同步的时候，也就是让所有这个类下面的对象共用同一把锁的时候，我们如何办呢？

看代码：

package com.jack.zhang.chapter9.classlock;

/**
 *
 * @author EX-LIUQI001
 *
 */
public class Test2 {
	public final static Byte[] locks = new Byte[0];

	public static void staticX() throws InterruptedException {
		synchronized (locks) {
			for (int i = 0; i < 10; i++) {
				Thread.sleep(1000);
				System.out.println("staticX.......................");
			}
		}
	}

	public void x() throws InterruptedException {
		synchronized (locks) {
			for (int i = 0; i < 10; i++) {
				Thread.sleep(1000);
				System.out.println("x.......................");
			}
		}
	}

	public static void main(String[] args) {
		final Test2 test1 = new Test2();
		Thread thread = new Thread(new Runnable() {
			public void run() {
				try {
					test1.x();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}, "a");

		Thread thread1 = new Thread(new Runnable() {
			public void run() {
				try {
					Test2.staticX();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}, "b");
		thread1.start();
		thread.start();
	}
}

运行结果：

staticX.......................

staticX.......................

staticX.......................

staticX.......................

staticX.......................

staticX.......................

staticX.......................

staticX.......................

staticX.......................

staticX.......................

x.......................

x.......................

x.......................

x.......................

x.......................

x.......................

x.......................

x.......................

x.......................

x.......................