当对象A包含对对象B的引用时，是否可以用Mapstruct将对象B的属性映射到对象A_DTO的属性？

Question

根据Mapstruct文档，通过为被引用的对象（对象B）定义映射方法，可以将一个对象（对象A）映射到D，该对象包含另一个对象（对象B）。但是如果我只需要映射那个对象（对象B）的属性而不是整个对象呢？

    fun AppUserEntity.toAppUserDetailsDTO() = AppUserDetailsDTO(
            id = id,
            username = appUserLogin,
            password = appUserPassword,
            authorities = roles.map { it.name },
            isEnabled               = isEnabled,
            isAccountNonLocked      = isAccountNonLocked,
            isAccountNonExpired     = isAccountNonExpired,
            isCredentialsNonExpired = isCredentialsNonExpired
    )

但是如何用Java和MapStruct来实现呢？

Answer 1

在Mapstruct上，可以使用注释的expression属性将一个方法用于注释的映射:expression=“java（yourJavaCodeHere）”。

您的映射器将如下所示：

@Mapper(componentModel = "spring")
public abstract class AppUserDetailsDtoMapper {

    @Mappings({
            @Mapping(target = "username", source = "appUserLogin"),
            @Mapping(target = "password", source = "appUserPassword"),
            @Mapping(target = "authorities", expression = "java( mapAuthorities(user.getRoles()) )")
    })
    public abstract AppUserDetailsDTO toAppUserDetailsDTO(AppUserEntity user);

    protected Collection<GrantedAuthority> mapAuthorities(Set<RoleEntity> roles) {
        // Map the authorities here
    }
}