使用枚举来实现策略模式

1. 使用很多if else的场景

   1. 	public void save(String type,Object data){if("db".equals(type)){saveInDb(data);}else if("file".equals(type)){saveInFile(data);}else if("oss".equals(type)){saveInOss(data);}}
      

2. 使用枚举来解决

   1. public enum SaveStrategyEnum{DB("db"){@Overridepublic void save(Object obj){System.out.println("save in db:"+obj);}},FILE("file"){@Overridepublic void save(Object obj){System.out.println("save in file:"+ obj);}},OSS("oss"){@Overridepublic void save(Object obj){System.out.println("save in oss:" +obj);}};private String type;SaveStrategyEnum(String type){this.type = type;}public abstract void save(Object obj);public static SaveStrategyEnum typeOf(String type){for(SaveStrategyEnum strategyEnum : values()){if(strategyEnum.type.equalsIgnoreCase(type)){return strategyEnum;}}return null;}
      }public void save(String type,Object data){SaveStrategyEnum strategyEnum = SaveStrategyEnum.typeOf(type);if(strategyEnum != null){strategyEnum.save(data);}
      }