java enum 笔记 日期时间格式化

java 的enum也是个类。

 

public   enum  Action {
    TURN_LEFT,
    TURN_RIGHT,
    SHOOT;
     public  String GetDescription(){
        
         switch ( this .ordinal()){
             case   0 :  return   " left " ;
             case   1 :  return   " right " ;
             case   2 :  return   " shoot " ;        
             default : return   null ;
        }        
    }    
}

 

 

e.g.2:

 

代码

public   enum  ActionAbstract {
    TURN_LEFT
    {        
         public  String GetDesc(){ return   " left " ;}
    },
    TURN_RIGHT{        
         public  String GetDesc(){ return   " right " ;}
    },
    SHOOT{        
         public  String GetDesc(){ return   " shoot " ;}
    };   // 以;结束
    
     public   abstract  String GetDesc();
}

 

 

ps:

 

  for(Action act : Action.values()){
   System.out.printf( "%s %s %n", act.ordinal() , act );
  }

//日期时间格式化表达式：

  System.out.println(
    String.format(  "%1$tY-%1$tm-%1$td %1$tH:%1$tM:%1$tS",new Date() )
    );
  System.out.printf("%1$tY-%1$tm-%1$td %1$tH:%1$tM:%1$tS",new Date() );