设计模式の单例模式

代码实现：

class Singleton{  private static Singleton instance;  private Singleton(){  }  public static Instance getInstance(){    if(instance==null)      lock(syncRoot){         if(instance==null){            instance=new Singleton();         }      }      return instance;  }}

饿汉式：

public class Singleton{    private static Singleton instance=new Singleton();      private Singleton(){};  //私有化构造方法    public static Singleton getInstance(){    return instance;    }   }