Are you tired of manually writing mapping code between Java bean classes? Meet MapStruct, your new best friend that will help you generate mappers effortlessly! This blog will walk you through everything you need to know to get started with MapStruct, from installation to code usage, while ensuring you have solutions at your fingertips in case you run into any hurdles along the way.

What is MapStruct?

MapStruct is a Java annotation processor that generates type-safe and efficient mappers for Java bean classes. It helps you avoid the tedious and error-prone task of manually writing mapping code. Here are some of the exceptional benefits of using MapStruct:

• Fast execution: Utilizes plain method calls instead of reflection.
• Compile-time type safety: Ensures objects and properties are correctly mapped, preventing mapping errors.
• Self-contained code: No additional runtime dependencies needed.
• Clear error reports: Easily identify incomplete or incorrect mappings at build time.
• Easily debuggable: The generated mapping code is straightforward to debug or manually edit.

Using MapStruct

Requirements

MapStruct requires Java 1.8 or later. Ensure you have the correct version of Java installed before proceeding.

Maven

For Maven-based projects, add the following to your POM file:

<properties>
    <org.mapstruct.version>1.6.2</org.mapstruct.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.mapstruct</groupId>
        <artifactId>mapstruct</artifactId>
        <version>$org.mapstruct.version</version>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.13.0</version>
            <configuration>
                <source>17</source>
                <target>17</target>
                <annotationProcessorPaths>
                    <path>
                        <groupId>org.mapstruct</groupId>
                        <artifactId>mapstruct-processor</artifactId>
                        <version>$org.mapstruct.version</version>
                    </path>
                </annotationProcessorPaths>
            </configuration>
        </plugin>
    </plugins>
</build>

Gradle

If you are using Gradle, follow the structure below:

plugins {
    // Only for Eclipse
    id 'com.diffplug.eclipse.apt' version '3.26.0'
}
dependencies {
    implementation 'org.mapstruct:mapstruct:1.6.2'
    annotationProcessor 'org.mapstruct:mapstruct-processor:1.6.2'
    testAnnotationProcessor 'org.mapstruct:mapstruct-processor:1.6.2' // For test code
}

Documentation and Getting Help

To learn more about MapStruct, visit the project homepage. For comprehensive information about its functionalities, check the reference documentation. If you have questions or need assistance, don’t hesitate to ask in the Discussions section.

Troubleshooting

If you run into issues such as incomplete mappings or build errors, consider the following troubleshooting steps:

• Ensure you have added correct dependencies in your project file (Maven or Gradle).
• Verify that you are using the supported Java version (Java 1.8 or later).
• Check for any missing mapping annotations in your mapper interface.
• Consult the clear error reports generated by MapStruct to pinpoint exact problems.

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Building from Source

If you want to build MapStruct from source, ensure you have Maven installed. Java 11 or later is required. To build the complete project, execute:

.mvnw clean install

To skip the distribution module, run:

.mvnw clean install -DskipDistribution=true

Importing into IDE

To seamlessly integrate MapStruct within your IDE, you must enable annotation processing. Here’s how:

IntelliJ

• Ensure you have at least IntelliJ version 2018.2.x or newer.
• Enable annotation processing from Build, Execution, Deployment – Compiler – Annotation Processors.

Eclipse

• Install the m2e_apt plugin for Eclipse.

Conclusion

At fxis.ai, we believe that such advancements are crucial for the future of AI, as they enable more comprehensive and effective solutions. Our team is continually exploring new methodologies to push the envelope in artificial intelligence, ensuring that our clients benefit from the latest technological innovations.