从未知字符串中检索枚举值

Question

我有一个中等大小的Enum，在这个Enum中我想从给定的字符串中检索值。例如,

GAUL_RAM("gaul_ram.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
GAUL_RAM_UPGRADED("gaul_ram_upgraded.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),  
GREEK_RAM("greek_ram.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
GREEK_RAM_UPGRADED("greek_ram_upgraded.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
PERSIA_RAM("persia_ram.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
PERSIA_RAM_UPGRADED("persia_ram_upgraded.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
CARTHAGE_RAM("carthage_ram.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
CARTHAGE_RAM_UPGRADED("carthage_ram_upgraded.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0));

我有上面的枚举。我可能会被传递一个值，比如“波斯”。然后，我要做的是从波斯常量PERSIA_RAM及其Location对象中提取字符串值。

然而，我没有看到一种“干净”的方式来做这件事。想到的解决方案是检查提供的字符串"persia"，通过Object[] possibleValues = enumValue.getDeclaringClass().getEnumConstants().toString().toLowerCase();遍历枚举中的所有值，然后在下划线“_”上使用某种分隔符，以获得枚举常量中的第一个单词。

再说一次，这不是一个圆滑的解决方案。有没有更好的方法来完成这项任务？

Answer 1

您可以在装入类时创建一个HashMap字符串来枚举，这样就不必在每次查找枚举值时都执行字符串操作。下面是我如何做到这一点的一个例子：

public class Testing {
    public static final HashMap<String, Enum> map = new HashMap<>();

    public static void main(String[] args) {
        for (Enum e : Enum.values()) {
            map.put(e.toString().toLowerCase().split("_")[0], e);
        }

        System.out.println(map.get("persia").getString());
    }

    public enum Enum {
        GAUL_RAM("gaul_ram.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
        GAUL_RAM_UPGRADED("gaul_ram_upgraded.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),  
        GREEK_RAM("greek_ram.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
        GREEK_RAM_UPGRADED("greek_ram_upgraded.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
        PERSIA_RAM("persia_ram.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
        PERSIA_RAM_UPGRADED("persia_ram_upgraded.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
        CARTHAGE_RAM("carthage_ram.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0)),
        CARTHAGE_RAM_UPGRADED("carthage_ram_upgraded.schem", new Location(Bukkit.getWorld(Statics.worldName), 0, 100, 0));

        private String arg0;
        private Location arg1

        private Enum (String s, Location l) {
            arg0 = s;
            arg1 = l
        }

        public String getString() {
            return arg0;
        }

        public Location getLoc() {
            return arg1;
        }
    }
}

这将返回：

persia_ram_upgraded.schem

请注意，这确实在您的一些枚举值之间留下了一些歧义。例如，PERSIA_RAM和PERSIA_RAM_UPGRADED都对应于"persia"字符串。我建议您重命名，或者重新考虑如何访问枚举值。