Java 包导入别名

2022-01-13 00:00:00 package import syntax java

在 Java 中是否可以导入包并为这个包导入一个特定的名称?

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

我目前有一个类，它使用来自后端和服务包的一些 DTO.在这两个包中，DTO 具有相同的名称.而且我认为这不太可读:

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);

这是一个小例子.该类实际上非常复杂，并且其中包含更多代码.

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

Java 是否有类似 import com.backend.mypackage.a.b.c.d.UserDto as userDtoBackend 这样我可以缩短我的源代码?

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

推荐答案

不行，不能import x as y;"在 Java 中.

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

您可以做的是扩展类，或为其编写一个包装类，然后导入该类.

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) {
        // ...
    }
}

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