How to map objects using @Mapper?

Question

I'm mapping objects using below code snippet

@Mapper
@Configuration
public interface CommentMapper {

    CommentMapper INSTANCE = Mappers.getMapper(CommentMapper.class);

    @Mapping(source = "Id", target = "Id")
    @Mapping(source = "remark", target = "remark")
    Comment getComment(CommentDto postDto);

    CommentDto getCommentDto(Comment post);

}

It doesnt map, but the moment I add this, it worked fine

@Mapper(imports = { Instant.class, DateTimeFormatter.class })

but not able to understand what it does? imports = { Instant.class, DateTimeFormatter.class } how its helping to map objects?

Answer 1

As it is written in documentation , with "imports" you can set:

Additional types for which an import statement is to be added to the generated mapper implementation class.

In your case - it means that in generated CommentMapperImpl class, which will be generated as a realization of CommentMapper interface, two lines will be presented:

import path.to.class.DateTimeFormatter; // for example: java.time.format.DateTimeFormatter
import path.to.class.Instant;

If you use gradle you can find CommentMapperImpl.java here:

build/generated/sources/annotationProcessor/java/main/your/mapper/interface/package/CommentMapperImpl.java

for maven:

target/generated-sources/annotations/your/mapper/interface/package/CommentMapperImpl.java