强制MapStruct使用自定义方法而不是dto值

Question

I have a UserDTO and User entity which I want to map. When creating a new User some fields (for example: password , modifiedBy ) must be generated by some custom method (for example: password is randomly generated and encoded, but modifiedBy username is retrieved from security service). For this I autowire some services into the mapper. Many of them return String and MapStruct cannot understand which one to use in each case and just uses the first it found on everything that accepts String as input.

@Mapper(componentModel = "spring", uses = PasswordEncoder.class)
public interface UserMapper {

@Mapping(target = "password", qualifiedByName = "PASS")
User mapUser(UserDto dto);

@Named("PASS")
default String getPass(PasswordEncoder passwordEncoder){
    return passwordEncoder.encode(some_random_generator);
    }
}

This generates code that just uses method from PasswordEncoder in any setter that accepts String and getPass(...) method is not used at all. However I need it to use my getPass(...) method on password field only.

Answer 1

Currently it is not possible to pass the used mapper or service to a default method. There is mapstruct/mapstruct#1637 open for that. Also you can't really do @Mapper( uses = PasswordEncoder.class ) as that would lead to all String to String to be mapped via the PasswordEncoder . What you can do though is to create your own custom PasswordEncoderMapper and use @Named on it, this way you would be in control.

This can look like this:

@Qualifier // org.mapstruct.Qualifier
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.CLASS)
public @interface EncodedMapping {
}

public class PasswordEncoderMapper {

    protected final PasswordEncoder passwordEncoder;

    public PasswordEncoderMapper(PasswordEncoder passwordEncoder) {
        this.passwordEncoder = passwordEncoder;
    }

    @EncodedMapping
    public String encode(String value) {
        return passwordEncoder.encode(value);
    }
}

@Mapper(componentModel = "spring", uses = PasswordEncoderMapper.class)
public interface UserMapper {

    @Mapping(target = "password", qualifiedBy = EncodedMapping.class)
    User mapUser(UserDto dto);
}

Regarding the modifiedBy property. You should do that as part of an @ObjectFactory or by using an expression.

With an expression this can look like:

@Mapper(componentModel = "spring", uses = PasswordEncoderMapper.class, imports = SecurityUtils.class)
public interface UserMapper {

    @Mapping(target = "password", qualifiedBy = EncodedMapping.class)
    @Mapping(target = "modifiedBy", expression = "java(SecurityUtils.getCurrentUserId())")
    User mapUser(UserDto dto);
}