从Java中的枚举获取int值

Question

I have enum

enum Number{
  FIRST(123),
  SECOND(321);
}

Number nr=Number.FIRST

How can I get an enum value (not a String but int ) from my variable nr without creating a new method?

Answer 1

In Java, enums are objects too. Provide a constructor for your numbers to be passed in, plus a public instance variable; no getter method necessary.

enum Num{
  FIRST(123),
  SECOND(321);
  public final int value;
  private Num(int value) { this.value = value; }
}

Answer 2

TL;DR: You can't.

Long version:

The code snippet you have above will not compile because you are missing the constructor:

private int value;

public Number(int i) {
    this.value = i;
}

After you've done that, then you will need to provide the getter for value :

public int getValue() {
    return this.value;
}

EDIT: If you really, really, don't want to create a new method, you can make the value field public , but you're violating the OO concept of encapsulation (ie, best practice).

Answer 3

You need to write your enum like this (also, do not call it Number please! There is java.lang.Number ):

enum MyNumber
{
    FIRST(123),
    SECOND(321);

    private final int number;

    MyNumber(final int number)
    {
        this.number = number;
    }

    public int getNumber()
    {
        return number;
    }
}

If you don't want an accessor, remove the getter and make number public.