为什么使用枚举而不是常量？哪个在软件设计和可读性方面更好 [英] Why use Enums instead of Constants? Which is better in terms of software design and readability

问题描述

我有一个场景，我有玩家类型ARCHER，WARRIOR和巫师。我应该在玩家类中使用什么？类型或枚举的String变量？为什么枚举和为什么Constant Strings。请帮助解释原因。

I have a scenario in which I have Player types ARCHER,WARRIOR, and sorcerer. What should I use in player class? A String variable for type or a Enum? Why enum and why Constant Strings. Please help with reasons.

推荐答案

假设您使用常量字符串（或 int 值 - 对他们来说也一样）：

Suppose you use constant strings (or int values - the same goes for them):

// Constants for player types
public static final String ARCHER = "Archer";
public static final String WARRIOR = "Warrior";

// Constants for genders
public static final String MALE = "Male";
public static final String FEMALE = "Female";

然后你最终不知道你的数据类型 - 导致可能不正确的代码：

then you end up not really knowing the type of your data - leading to potentially incorrect code:

String playerType = Constants.MALE;

如果你使用枚举，那最终会是：

If you use enums, that would end up as:

// Compile-time error - incompatible types!
PlayerType playerType = Gender.MALE;

同样，枚举提供一组受限制的值：

Likewise, enums give a restricted set of values:

String playerType = "Fred"; // Hang on, that's not one we know about...

vs

PlayerType playerType = "Fred"; // Nope, that doesn't work. Bang!

此外，Java中的枚举可以有更多与之相关的信息，也可能有行为。全面好多了。

Additionally, enums in Java can have more information associated with them, and can also have behaviour. Much better all round.

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