一、在多線程環境下創建單例
方式一：
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package com.ietree.multithread.sync;public class Singletion { private static class InnerSingletion { private static Singletion single = new Singletion(); } public static Singletion getInstance() { return InnerSingletion.single; }} |
方式二：
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package com.ietree.multithread.sync;public class DubbleSingleton { private static DubbleSingleton ds; public static DubbleSingleton getDs() { if (ds == null) { try { // 模擬初始化對象的準備時間... Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } synchronized (DubbleSingleton.class) { if (ds == null) { // 這個判斷很重要，如果沒有那將不是單例，而是多例 ds = new DubbleSingleton(); } } } return ds; } public static void main(String[] args) { Thread t1 = new Thread(new Runnable() { @Override public void run() { System.out.println(DubbleSingleton.getDs().hashCode()); } }, "t1"); Thread t2 = new Thread(new Runnable() { @Override public void run() { System.out.println(DubbleSingleton.getDs().hashCode()); } }, "t2"); Thread t3 = new Thread(new Runnable() { @Override public void run() { System.out.println(DubbleSingleton.getDs().hashCode()); } }, "t3"); t1.start(); t2.start(); t3.start(); }} |
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原文鏈接：http://www.cnblogs.com/Dylansuns/p/6719764.html
