Java Package Import Alias [duplicate]

问题:

This question already has an answer here:

• Change Name of Import in Java, or import two classes with the same name 5 answers

Is it possible in Java to import packages and give this package import a specific name?

I currently have a class, which uses some DTO's from a backend and a service package. In both packages the DTO's have the same name. And I think this isn't quite readable:

com.backend.mypackage.a.b.c.d.UserDto userBackend = new com.backend.mypackage.a.b.c.d.UserDto();
com.service.mypackage.a.b.c.d.UserDto userService = new com.service.mypackage.a.b.c.d.UserDto();

mapper(userBackend, userService);

This is a small example. The class is actually quite complex and has a lot more code in it.

Does Java have something like import com.backend.mypackage.a.b.c.d.UserDto as userDtoBackend so i can shorten my source code?

回答1:

No, you can not do "import x as y;" in Java.

What you CAN do is to extend the class, or write a wrapper class for it, and import that one instead.

import com.backend.mypackage.a.b.c.UserDto;

public class ImportAlias {
    static class UserDtoAlias extends com.backend.mypackage.a.b.c.d.UserDto {
    }

    public static void main(String[] args) {
        UserDto userBackend = new UserDto();
        UserDtoAlias userService = new UserDtoAlias();

        mapper(userBackend, userService);
    }

    private static void mapper(UserDto userBackend, UserDtoAlias userService) {
        // ...
    }
}

回答2:

There is no way to do this in Java.