MapStruct属性映射失效求助：无法识别DTO属性

问题现象 #

在Spring Boot项目中使用MapStruct 1.5.5.Final进行对象映射时，出现以下异常情况：

• 定义的Mapper接口生成的实现类未执行任何属性映射，直接返回空的Builder实例
• 手动添加@Mapping注解后，编译报错：No property named "name" exists in source parameter(s). Type "SignUpRequestDTO" has no properties.

相关代码 #

SignUpRequestDTO类 #

package ez.ndvz.application.api.v1.dto.authenticationDTOs;
@Data
@Builder
public class SignUpRequestDTO {

    @NonNull
    @NotBlank
    String name;

    @NotBlank
    @NonNull
    String lastName;

    @NonNull
    @NotBlank
    @Pattern(regexp = "^\\+(389)\\s?([2-7]0|78|77|75|76|71|72|73|74)\\s?([0-9]{6})$", message = "Invalid phone number format for North Macedonia")
    String phoneNumber;

    @NotBlank
    @NonNull
    @Email
    String email;

    @NonNull
    @NotBlank
    @Size(min = 6)
    String password;
}

User领域类 #

package ez.ndvz.core.domain.models;
@AllArgsConstructor
@Builder
@Getter
@Setter
public class User {
    private Long id;

    private String name;

    private String lastName;

    private String phoneNumber;

    private String email;

    private String password;

    private Set<Roles> roles;

    private List<Property> propertyList;
}

Mapper接口 #

package ez.ndvz.application.api.v1.mapper;
@Mapper(componentModel = "spring")
public interface UserHttpMapper {
    User toDomain(SignUpRequestDTO signUpRequestDTO);

    User toDomain(SignInRequestDTO signInRequestDTO);

    UserEntity toEntity(SignInRequestDTO signInRequestDTO);

    UserEntity toEntity(SignUpRequestDTO signUpRequestDTO);
}

生成的实现类（无属性映射） #

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2024-02-14T11:32:45+0100",
    comments = "version: 1.5.5.Final, compiler: IncrementalProcessingEnvironment from gradle-language-java-8.2.jar, environment: Java 19.0.2 (Amazon.com Inc.)"
)
@Component
public class UserHttpMapperImpl implements UserHttpMapper {

    @Override
    public User toDomain(SignUpRequestDTO signUpRequestDTO) {
        if ( signUpRequestDTO == null ) {
            return null;
        }

        User.UserBuilder user = User.builder();

        return user.build();
    }

    @Override
    public User toDomain(SignInRequestDTO signInRequestDTO) {
        if ( signInRequestDTO == null ) {
            return null;
        }

        User.UserBuilder user = User.builder();

        return user.build();
    }

    @Override
    public UserEntity toEntity(SignInRequestDTO signInRequestDTO) {
        if ( signInRequestDTO == null ) {
            return null;
        }

        UserEntity.UserEntityBuilder userEntity = UserEntity.builder();

        return userEntity.build();
    }

    @Override
    public UserEntity toEntity(SignUpRequestDTO signUpRequestDTO) {
        if ( signUpRequestDTO == null ) {
            return null;
        }

        UserEntity.UserEntityBuilder userEntity = UserEntity.builder();

        return userEntity.build();
    }
}

手动添加@Mapping后的报错信息 #

error: No property named "name" exists in source parameter(s). Type "SignUpRequestDTO" has no properties.
    User toDomain(SignUpRequestDTO signUpRequestDTO)

Gradle依赖配置 #

dependencies {
    implementation project(':domain')
    implementation project(':infrastructure:persistance')
    implementation project(':infrastructure:authentication')

    implementation 'org.mapstruct:mapstruct:1.5.5.Final'
    annotationProcessor 'org.mapstruct:mapstruct-processor:1.5.5.Final'

    implementation 'jakarta.validation:jakarta.validation-api:3.0.2'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.projectlombok:lombok:1.18.28'
    annotationProcessor 'org.projectlombok:lombok:1.18.28'

    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

问题原因 #

核心问题是Lombok与MapStruct的注解处理器执行顺序冲突：MapStruct注解处理器先于Lombok运行，此时Lombok尚未生成@Data、@Builder对应的getter/setter方法和Builder逻辑，导致MapStruct无法识别DTO和实体类中的属性，进而无法生成映射代码。

解决方案 #

通过添加lombok-mapstruct-binding依赖，强制Lombok先于MapStruct执行注解处理，确保MapStruct能识别到Lombok生成的属性。

修改后的Gradle依赖配置如下：

dependencies {
    implementation project(':domain')
    implementation project(':infrastructure:persistance')
    implementation project(':infrastructure:authentication')

    implementation 'org.mapstruct:mapstruct:1.5.5.Final'
    annotationProcessor 'org.mapstruct:mapstruct-processor:1.5.5.Final'

    implementation 'jakarta.validation:jakarta.validation-api:3.0.2'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.projectlombok:lombok:1.18.28'
    annotationProcessor 'org.projectlombok:lombok:1.18.28'
    // 添加绑定依赖，确保Lombok优先处理
    annotationProcessor 'org.projectlombok:lombok-mapstruct-binding:0.2.0'

    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

验证效果 #

修改依赖后重新编译项目：

1. MapStruct会自动识别同名属性并生成完整映射逻辑，无需手动添加@Mapping注解
2. 生成的实现类会正确调用Builder方法设置对应属性，示例如下：

@Override
public User toDomain(SignUpRequestDTO signUpRequestDTO) {
    if ( signUpRequestDTO == null ) {
        return null;
    }

    User.UserBuilder user = User.builder();

    user.name( signUpRequestDTO.getName() );
    user.lastName( signUpRequestDTO.getLastName() );
    user.phoneNumber( signUpRequestDTO.getPhoneNumber() );
    user.email( signUpRequestDTO.getEmail() );
    user.password( signUpRequestDTO.getPassword() );

    return user.build();
}

内容的提问来源于stack exchange，提问作者Nisi Zenuni