1、懒汉模式

public class Single{

     private static Single single；

    private Single(){}

     public static Single getSingle(){

         if(single==null)

            single=new Single();

       return single;

    }

}

2、；懒汉模式（线程安全）

public class Single{

private static Single singel;

private Single(){}

public static Synchronized Single getSingle(){

   if(single==null)

      single=new Single();

return single;

}

} 

3、恶汉模式

public class Single{

private static Single single=new Single();

private Single();

  public static Single getSingle(){

                return single;

}

}

4、恶汉模式2

public class Single{

private static Single single;

private Single(){single=new Single()};

public static Single getSingle(){

return single;

}

}

5、双重检测模式

public class Single{

private static Single single;

private Single(){};

public static Single getSingle(){

  if(single==null){

  Synchronized (Single.class){

     if(single==null)

        single=new Single();

}

}

return single;

}

}

6、静态内部类模式（推荐）

public class Single{

private static class SingleInner{

  private static final Single single=new Single();

}

private Single(){}

private 

}