如何从 String 值中查找 Java 枚举? [英] How can I lookup a Java enum from its String value?

问题描述

我想从其字符串值(或可能的任何其他值)中查找枚举.我已经尝试了以下代码，但它不允许在初始化程序中使用静态.有没有简单的方法?

I would like to lookup an enum from its string value (or possibly any other value). I've tried the following code but it doesn't allow static in initialisers. Is there a simple way?

public enum Verbosity {

    BRIEF, NORMAL, FULL;

    private static Map<String, Verbosity> stringMap = new HashMap<String, Verbosity>();

    private Verbosity() {
        stringMap.put(this.toString(), this);
    }

    public static Verbosity getVerbosity(String key) {
        return stringMap.get(key);
    }
};

推荐答案

使用为每个 Enum 自动创建的 valueOf 方法.

Use the valueOf method which is automatically created for each Enum.

Verbosity.valueOf("BRIEF") == Verbosity.BRIEF

对于任意值以:

public static Verbosity findByAbbr(String abbr){
    for(Verbosity v : values()){
        if( v.abbr().equals(abbr)){
            return v;
        }
    }
    return null;
}

如果您的分析器告诉您，请稍后再转到 Map 实现.

Only move on later to Map implementation if your profiler tells you to.

我知道它正在迭代所有值，但只有 3 个枚举值几乎不值得做任何其他努力，事实上，除非您有很多值，否则我不会为 Map 烦恼它会足够快.

I know it's iterating over all the values, but with only 3 enum values it's hardly worth any other effort, in fact unless you have a lot of values I wouldn't bother with a Map it'll be fast enough.

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