Java枚举类型名称反映

Question

I want to retrieve the name of the enum type from within the enum type itself:

enum Mammals {
    DOG(new Dog()),
    CAT(new Cat());

    public String alias;

    Mammals(AncestorOfDogAndCat a){
        this.alias=this.getClass().getName().toLowerCase();
        System.out.println(alias);
    }
}

When I instance them I get

Main$mammals
Main$mammals

but I want

dog
cat

Answer 1

Don't use reflection. It's not robust enough. Provide a method which provides this information.

interface Animal
{
    String getName();
}

class Dog implements Animal
{
    public String getName()
    {
        return "dog";
    }
}

enum Mammals {
    DOG(new Dog()),
    CAT(new Cat());

    public String alias;

    Mammals (Animal animal) {
        this.alias = animal.getName();
        System.out.println(alias);
    }
}

Answer 2

You can use the name() method on an enum constant to get the name of the enum constant:

enum Mammals {
    DOG(),
    CAT();

    public String alias;

    Mammals() {
        this.alias = name().toLowerCase();
        System.out.println(alias);
    }
}

The name() method is something that is automatically added by the compiler on enum types.

Answer 3

enum Mammals {
    DOG(new Dog()),
    CAT(new Cat());

    public String alias;

    Mammals(DogOrCat value){
        this.alias=name().toLowerCase();
        System.out.println(alias);
    }
}

or use toString() , which by default is implemented using name .

Answer 4

Using this.getClass() will return the name of the class itself, which is the enum Mammals here. Instead take in a parameter and use getClass on the parameter for your alias.

enum Mammals {
DOG(new Dog()),
CAT(new Cat());

public String alias;

  Mammals(Animal an){
      this.alias=an.getClass().getName().toLowerCase();
      System.out.println(alias);
  }
}

where Dog and Cat extend Animal.