Java单例模式

<pre name="code" class="java"><span style="font-size:18px;color:#FF0000;">恶汉模式：</span>

public class MediaPlayer { //饿汉模式创建单例
//创建私有静态实例
private static MediaPlayer player=new MediaPlayer(); //收回该类的实例的创建权限（私有构造方法） private MediaPlayer(){} //公有方法，让外界获得该实例 public static MediaPlayer getInstance(){ return player; } public void play(){ System.out.println("正在播放东风破……"); }}

懒汉模式：

<span style="font-size:18px;">public class MediaPlayer2 {//懒汉模式（layz load）延迟加载private  static MediaPlayer2 player2=null;//私有化构造方法private MediaPlayer2(){}public static MediaPlayer2 getInstance(){if(player2==null){player2=new MediaPlayer2();}return player2;}public void play(){System.out.println("正在播放菊花台……");}}</span>

测试类：

<span style="font-size:18px;">public class Test {public static void main(String[] args) {MediaPlayer player=MediaPlayer.getInstance();player.play();MediaPlayer player1=MediaPlayer.getInstance();player1.play();if (player==player1) {System.out.println("同一单例");}else {System.out.println("不同单例");}System.out.println("----------------------------------------------");MediaPlayer2 player2=MediaPlayer2.getInstance();player2.play();MediaPlayer2 player3=MediaPlayer2.getInstance();player3.play();if (player2==player3) {System.out.println("同一单例");}else {System.out.println("不同单例");}}}</span>

测试结果：

正在播放东风破……

正在播放东风破……
同一单例
----------------------------------------------
正在播放菊花台……
正在播放菊花台……
同一单例