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线程静态同步与非静态差别

2024-10-27 12:26:39   209人阅读

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.......................  

线程静态同步与非静态差别


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