如何使用 id 检索 Enum 名称? [英] How to retrieve Enum name using the id?

问题描述

我有 enum 为:

public enum EnumStatus {

    PASSED(40L, "Has Passed"),
    AVERAGE(60L, "Has Average Marks"),
    GOOD(80L, "Has Good Marks");

    private java.lang.String name;

    private java.lang.Long id;

    EnumStatus(Long id, java.lang.String name) {
        this.name = name;
        this.id = id;
    }

    public java.lang.String getName() {
        return name;
    }

    public java.lang.Long getId() {
        return id;
    }
}

我必须仅使用 id(40,60, 80)获取枚举名称(PASSED、AVERAGE、GOOD).我该怎么做?

I have to get the Enum names(PASSED, AVERAGE, GOOD) using the ids only(40,60, 80). How do I do it?

推荐答案

在您的 enum 中创建一个静态方法，该方法在 values 中搜索(隐式方法/成员，不要t 确切知道它是哪个)并返回相应的值.对于方法找不到匹配值的情况，您应该创建一个特殊条目，例如UNKNOWN，您可以返回.这样，您就不必返回 null，这总是一个坏主意.

Create a static method in your enum which searches in values (implicit method/member, don't know exactly which is it) and returns the corresponding value. For cases in which the method can not find a matching value, you should create a special entry, e.g. UNKNOWN, which you can return. This way, you do not have to return null, which is always a bad idea.

public static EnumStatus getById(Long id) {
    for(EnumStatus e : values()) {
        if(e.id.equals(id)) return e;
    }
    return UNKNOWN;
}

顺便说一句 - 你的代码似乎是错误的.GOOD 后面的括号似乎不属于那里.

Btw - your code seems to be wrong. The bracket after GOOD seems to not belong there.

这篇关于如何使用 id 检索 Enum 名称?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！