如何根据一个值找到一个枚举? [英] How to find an enum according to a value?

问题描述

我正在使用一个看起来像这样的(旧版，不可更改)枚举:

I'm working with a (legacy, not changeable) enum that looks like this:

enum MsgEnum {
   private int number;
   private int msg;

   MSG_OK("OK", 0);
   MSG_NOK("NOK, 1);
   //lots of other messages

   private MsgEnum(String msg, int number) {
      this.msg = msg;
      this.number = number;
   }
}

如果我有 number ，如何最好地找出哪个 MsgEnum 与该数字匹配(假设它们是唯一的)?

If I have the number, how could I best find out which MsgEnum matches the number (assuming they are unique)?

除了以下内容之外，还有其他更好的方法吗?

Is there any better way apart from the following?

class MyEnumHelper() {

    public static MsgEnum MsgEnumfromNumber(int number) {
        for (MsgEnum m : MsgEnum.values()) {
            if (m.getNumber() == number) {
                return m;
            }
        }
        return null;
    }
}

推荐答案

您可以在Helper中声明一个静态Map，并使用静态方法getMsgEnumFromInteger(int)对其进行访问.像这样的东西:

You can declare a static Map in your Helper and access it using a static method getMsgEnumFromInteger(int). Something like :

private static final Map<Integer, MsgEnum> INT_TO_ENUM = new HashMap<Integer, MsgEnum>();

static {
    for (MsgEnum msgE : MsgEnum.values) {
        INT_TO_ENUM.put(msgE.getNumber(), msgE);
    }
}

public static MsgEnum getByInt(int number) {
    return INT_TO_ENUM.get(number);
}

(很抱歉，如果有错误，^^时还没有Java env)

(sorry if there are errors, it don't have a Java env at the moment ^^ )

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