MapStruct mapper returns empty mapped object

Question

I'm trying to use MapStruct to map convert between dto and entity objects, however the generated mapper implementation only returns empty mapped object.

BeerMapperImpl

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2020-11-05T07:42:21+0800",
    comments = "version: 1.3.0.Final, compiler: javac, environment: Java 11 (Oracle Corporation)"
)
@Component
public class BeerMapperImpl implements BeerMapper {

    @Override
    public BeerDto beerToBeerDto(Beer beer) {
        if ( beer == null ) {
            return null;
        }

        BeerDto beerDto = new BeerDto();

        return beerDto;
    }
}

Below are my codes.

pom.xml

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>
<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct</artifactId>
    <version>1.3.0.Final</version>
</dependency>

.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.8.0</version>
    <configuration>
        <annotationProcessorPaths>
            <path>
                <groupId>org.mapstruct</groupId>
                <artifactId>mapstruct-processor</artifactId>
                <version>1.3.0.Final</version>
            </path>
            <path>
                <groupId>
                    org.projectlombok
                </groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
            </path>
        </annotationProcessorPaths>
        <compilerArgs>
            <compilerArg>
                -Amapstruct.defaultComponentModel=spring
            </compilerArg>
        </compilerArgs>
    </configuration>
</plugin>

BeerMapper.java

@Mapper(uses = {DateMapper.class})
public interface BeerMapper {
    BeerDto beerToBeerDto(Beer beer);
    Beer beerDtoToBeer(Beer dto);
}

Anyone can help to advise what might go wrong in my codes? Thanks!

stackoverflow.com/questions/47676369/…

Guram Kankava
– Guram Kankava

2020-12-21 17:18:09 +00:00
Commented Dec 21, 2020 at 17:18 — Guram Kankava
– Guram Kankava, Commented Dec 21, 2020 at 17:18

Yassir Khaldi · Accepted Answer · 2022-01-13 12:08:31Z

52

I have found the solution without having to downgrade spring boot. The problem was that I was using lombok to generate getters and setters, on the other side mapstruct looks for getters and setters in your objects to populate them, but in this case it couldn't find them simply because during the compilation mapstruct was running before lombok could generate them.

The solution is simply to write the configuration of lombok before the configuration of mapstruct in your pom.xml file to execute lombok in first place. Make sure to run clean compile to delete old files.

Working configuration of maven-compiler-plugin:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-compiler-plugin</artifactId>
  <version>3.8.1</version>
  <configuration>
    <source>1.8</source>
    <target>1.8</target>
    <annotationProcessorPaths>
      <!--Project Lombok compile preprocessor-->
      <path>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>${lombok.version}</version>
      </path>
      <!--Maps Struct compile preprocessor-->
      <path>
        <groupId>org.mapstruct</groupId>
        <artifactId>mapstruct-processor</artifactId>
        <version>${mapstruct-ver}</version>
      </path>
    </annotationProcessorPaths>
  </configuration>
</plugin>

edited Jan 13, 2022 at 12:08

answered Apr 11, 2021 at 14:33

Yassir Khaldi

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8 Comments

Wedson Quintanilha da Silva Over a year ago

Perfect! A detail that is not well described when combining the two technologies. Solved my problem!

Prem Over a year ago

Can you please add solution for gradle

Safwan Shaikh Over a year ago

Perfect Answer!

MohammadBaqer Over a year ago

well explained :)

Marci Over a year ago

Reordering annotation processors works for Gradle as well. Thanks for the answer!

|

jiangwensi · Accepted Answer · 2020-11-05 02:45:05Z

1

I resolved this issue after downgrading spring boot starter from 2.3.5.RELEASE to 2.1.5.RELEASE.

answered Nov 5, 2020 at 2:45

jiangwensi

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Comments

Guram Kankava · Accepted Answer · 2020-12-21 17:51:44Z

1

I removed annotation Processor Paths tag and declared bot lombok and mapstruct as dependency.

link with similar issue: MapStruct and Lombok not working together

edited Dec 21, 2020 at 17:51

answered Dec 21, 2020 at 17:38

Guram Kankava

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Comments

Brad Jones · Accepted Answer · 2021-02-25 19:30:34Z

0

I've encountered a similar problem where all the values in the object created by the mapstruct mapping had null values when the original object was populated. When I checked the generated mapper in target the generated implementation did not contain an actual mapping. I found that this was easily fixed when I made a small change to the Mapper in my project and saved it. The mapper in target was re-generated with the mapping in place. I'm not sure why the mapper was generated incorrectly but this was a qick fix that worked for me.

answered Feb 25, 2021 at 19:30

Brad Jones

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1 Comment

Jin Kwon Jan 24 at 7:54

So, what's the qick fix? Please?

Rostyslav Pryimak · Accepted Answer · 2022-06-01 17:13:44Z

0

To the dto I added a @AllArgsConstructor, after removing it - works fine. Stupid, but works. The order of dependencies and paths was good, and spring boot version was older then proposed to downgrade

answered Jun 1, 2022 at 17:13

Rostyslav Pryimak

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1 Comment

Community Over a year ago

As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center.

jhonromanoft · Accepted Answer · 2023-03-27 16:24:07Z

0

As official documentation suggest, newer versions of lombok require an aditional anotation processor dependency so you would need to add a new annotation processor like so (maven)

<path>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok-mapstruct-binding</artifactId>
  <version>***</version>
</path>

make sure you add the latest version compatible with your gradle build

for gradle users it will be something like this

annotationProcessor 'org.projectlombok:lombok-mapstruct-binding'

this way it will work with no problem in new versions of spring

answered Mar 27, 2023 at 16:24

jhonromanoft

1

Comments

Patrick Chimeudeonwo · Accepted Answer · 2024-05-05 06:27:25Z

0

When using mapstruct with lombok, the position of the dependencies plays role on how mapstruct generates mapper implementation. just like > Yassir Khaldi already explained with the getters and setters logic of both mapstruct and lombok. especially if you are using gradle, ensure that the lombok dependency comes before mastruct dependency

***
compileOnly 'org.projectlombok:lombok'
annotationProcessor 'org.projectlombok:lombok'
implementation 'org.mapstruct:mapstruct:1.5.5.Final'
***

answered May 5, 2024 at 6:27

Patrick Chimeudeonwo

11 silver badge2 bronze badges

Comments

Yan Frankovski · Accepted Answer · 2024-10-02 13:04:34Z

0

In case that you already have lombok-mapstruct-binding dependency and still get the same empty result:

Make sure use didn't forget to add @Setter, @Getter and constructor annotation from lombok to your target class.

Mapstrcut seems to quietly skip fields that it can't set or get without even a warning.

answered Oct 2, 2024 at 13:04

Yan Frankovski

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