从枚举值获取枚举名称 [英] get enum name from enum value

问题描述

我已经阅读了很多关于如何使用java从其值中获取相应名称的枚举，但没有任何示例似乎适用于我！有什么问题？

I've read a lot about how obtain the corresponding name of an enum from its value using java, but no example seems to work for me! What is wrong?

public class Extensions {


    public enum RelationActiveEnum
    {
        Invited(0),
        Active(1),
        Suspended(2);

        private final int value;

        private RelationActiveEnum(final int value) {
            this.value = value;
        }
    }

}

和另一个类我使用：

        int dbValue = supp.ACTIVE;
        Extensions.RelationActiveEnum enumValue(dbValue);
        String stringName = enumValue.toString(); //Visible
        // OR
        int dbValuee = supp.ACTIVE;
        String stringValue = Enum.GetName(typeof(RelationActiveEnum), dbValue);

我应该工作，对吧？但它不!!!!它告诉我，dbValue插件被转换为RelationActiveEnum ...

I should work, right? but it doesn't!!!! it tells me that dbValue cannote be cast to RelationActiveEnum...

推荐答案

由于你的价值也恰好与ordinals匹配可以这样做：

Since your 'value' also happens to match with ordinals you could just do:

public enum RelationActiveEnum {
    Invited,
    Active,
    Suspended;

    private final int value;

    private RelationActiveEnum() {
        this.value = ordinal();
    }
}

从值获取枚举：

int value = 1;
RelationActiveEnum enumInstance = RelationActiveEnum.values()[value];

我想一个静态方法将是一个好的地方：

I guess an static method would be a good place to put this:

public enum RelationActiveEnum {
     public static RelationActiveEnum fromValue(int value) 
             throws IllegalArgumentException {
         try {
              return RelationActiveEnum.values()[value]
         } catch(ArrayIndexOutOfBoundsException e) {
              throw new IllegalArgumentException("Unknown enum value :"+ value);
         }
     }
}   

显然这一切都分崩离析你的'值'与枚举序号不一样。

Obviously this all falls apart if your 'value' isn't the same value as the enum ordinal.

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