java - 如何让 switch case 在 Java 中接受多种数据类型？

Question

虽然使用 Java switch case，它只接受 char 和 int，但我想提供字符串 case。如何做到这一点？

Answer 1

你不能在 switch-case 中有字符串(目前)。 It's on its way in Java 7.

目前接受的类型包括char, byte, short, int, Character 、Byte、Short、Integer 或枚举类型。

来自 Java 语言规范:

The type of the Expression must be char, byte, short, int, Character, Byte, Short, Integer, or an enum type (§8.9), or a compile-time error occurs.

...

All of the following must be true, or a compile-time error will result:

• Every case constant expression associated with a switch statement must be assignable (§5.2) to the type of the switch Expression.
• No switch label is null.
• No two of the case constant expressions associated with a switch statement may have the same value.
• At most one default label may be associated with the same switch statement.