java 类的static块

来源：互联网发布：unity3d 烘焙编辑：程序博客网时间：2024/05/16 15:36

偶然的想法：测试static块在多线程环境下是否也只能够执行一次

package com.study.thread;/**  * 测试多线程同步下是否出现同时访问一个静态类的static块 * @author CrazyPig * */public class ThreadSyn {private static int count = 0;static {System.out.println("start static block");try {Thread.sleep(5000);} catch(InterruptedException e) {System.out.println("线程中断异常");}count ++;System.out.println("end static block");}public static void print() {System.out.println("count = " + count);}public void print0() {System.out.println("print0()");}public static void main(String[] args) {Thread t1 = new Thread(new Runnable() {@Overridepublic void run() {// 确保调用staticThreadSyn.print();}});Thread t2 = new Thread(new Runnable() {@Overridepublic void run() {// TODO Auto-generated method stubThreadSyn newInstance = new ThreadSyn();newInstance.print0();}});t1.start();t2.start();}}

通过测试结果，证明类的static块在多线程环境下也只能够执行一次，由JVM来保证这一点

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