如何指导Mapstruct使用lombok Builder？

Question

当我试图用一个私有的默认构造函数映射对象时，MapStruct无法创建一个实现，而是使用一个（lombok生成的）构建器。

@Value
@Builder
public class SomeDto {
}

@Value
@Builder
public class SomeModel {
}

@Mapper
public interface SomeMapper {
    SomeDto map(SomeModel someModel);
    SomeModel map(SomeDto someDto);
}

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>${compiler-plugin.version}</version>
        <configuration>
            <annotationProcessorPaths>
                <path>
                    <groupId>org.projectlombok</groupId>
                    <artifactId>lombok</artifactId>
                    <version>1.18.16</version>
                </path>
                <path>
                    <groupId>org.projectlombok</groupId>
                    <artifactId>lombok-mapstruct-binding</artifactId>
                    <version>0.2.0</version>
                </path>
                <path>
                    <groupId>org.mapstruct</groupId>
                    <artifactId>mapstruct-processor</artifactId>
                    <version>1.4.1.Final</version>
                </path>
            </annotationProcessorPaths>
        </configuration>
    </plugin>

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2021-01-29T13:47:46+0100",
    comments = "version: 1.4.1.Final, compiler: javac, environment: Java 11.0.9.1 (Ubuntu)"
)
public class SomeMapperImpl implements SomeMapper {

    @Override
    public SomeDto map(SomeModel someModel) {
        if ( someModel == null ) {
            return null;
        }

        SomeDto someDto = new SomeDto();

        return someDto;
    }

    @Override
    public SomeModel map(SomeDto someDto) {
        if ( someDto == null ) {
            return null;
        }

        SomeModel someModel = new SomeModel();

        return someModel;
    }
}

为了重现这个问题，复制这个repo https://github.com/rmvanderspek/mapstruct-demo和mvn verify。

Answer 1

我已经使用了您的演示源码，结果发现将Mapstruct放在编译器插件源码中可以解决这个问题。我不知道为什么这样做，这对我来说是违反直觉的，但这是Mapstruct的一名开发人员在Lombok的GitHub上发布的类似问题中提出的建议。

所以在你的情况下：

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>${compiler-plugin.version}</version>
    <configuration>
        <annotationProcessorPaths>
            <path>
                <groupId>org.mapstruct</groupId>
                <artifactId>mapstruct-processor</artifactId>
                <version>${org.mapstruct.mapstruct-processor.version}</version>
            </path>
            <path>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${org.projectlombok.lombok.version}</version>
            </path>
            <path>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok-mapstruct-binding</artifactId>
                <version>${org.projectlombok.ombok-mapstruct-binding.version}</version>
            </path>
        </annotationProcessorPaths>
    </configuration>
</plugin>