在Java7之前，switch只能支持 byte、short、char、int或者其對應的封裝類以及Enum類型。

Java7可以使用String作為判斷條件

1. public?class?Test?{??
2. ??
3. ????public?void?test(String?str)?{??
4. ????????switch(str)?{??
5. ????????case?"abc":??
6. ????????????System.out.println("abc");??
7. ????????????break;??
8. ????????case?"def":??
9. ????????????System.out.println("def");??
10. ????????????break;??
11. ????????default:??
12. ????????????System.out.println("default");??
13. ????????}??
14. ????} ?

Java7之前如果要使用String作為判斷條件可以通過Enum來實現

1. public?enum?Animal?{??
2. ????dog,?cat,?bear;??
3. ??
4. ????public?static?Animal?getAnimal(String?animal)?{??
5. ????????return?valueOf(animal.toLowerCase());??
6. ????}??
7. } ?

1. public?class?Client?{????
2. ????
3. ????public?void?caseAnimal(String?animal){????
4. ????????switch(Animal.getAnimal(animal)){????
5. ????????case?cat:????
6. ????????????System.out.println("this?is?a?cat");????
7. ????????????break;????
8. ????????case?dog:????
9. ????????????System.out.println("this?is?a?dog");????
10. ????????????break;????
11. ????????case?bear:????
12. ????????????System.out.println("this?is?a?bear");????
13. ????????????break;????
14. ????????}????
15. ????}????
16. ????/**??
17. ?????*?@param?args??
18. ?????*/????
19. ????public?static?void?main(String[]?args)?{????
20. ????????????Client?client?=?new?Client();????
21. ????????????client.caseAnimal("cat");????
22. ????}????
23. } ?