~nyg/example-java-querydsl

#example-querydsl

#Introduction

In this example we have two Maven modules:

entities, which contains only JPA entities,
jpa, which contains the EntityManagerFactory initialization and calls to QueryDSL's JPAQueryFactory in order to perform a database requests.

The entities module is meant to not have any dependency on QueryDSL, and jpa is supposed to include the entities dependency in order to generate the QueryDSL query type classes (Q* classes). This is supposed to be done by the querydsl-maven-plugin but it currently does not work (see querydsl#3462).

Instead, the querydsl-apt dependency with the jakarta classifier was added to the entities module, so that query type classes are generated and can be used by the jpa module.

#`querydsl-maven-plugin`

The querydsl-maven-plugin should be used if the JPA annotated sources are not available. Here is a configuration example which works with Jakarta (note the usage of the javax.persistence-api, necessary due to an issue with the plugin).

<plugin>
    <groupId>com.querydsl</groupId>
    <artifactId>querydsl-maven-plugin</artifactId>
    <version>${querydsl.version}</version>
    <dependencies>
        <dependency>
            <groupId>javax.persistence</groupId>
            <artifactId>javax.persistence-api</artifactId>
            <version>2.2</version>
        </dependency>
    </dependencies>
    <executions>
        <execution>
            <phase>process-classes</phase>
            <goals>
                <goal>jpa-export</goal>
            </goals>
            <configuration>
                <targetFolder>target/generated-sources/java</targetFolder>
                <packages>
                    <package>edu.self.nyg.example.querydsl.entity</package>
                </packages>
            </configuration>
        </execution>
    </executions>
</plugin>

#`maven-compiler-plugin`

If the configuration of the maven-compiler-plugin needs to be modified (e.g. to add lombok annotation processing with mapstruct), it is necessary to add the last two dependencies in the annotation processor path:

<configuration>
    <annotationProcessorPaths>
        <!-- To process lombok annotations -->
        <path>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>${lombok.version}</version>
        </path>
        <!-- To generate QueryDSL type classes -->
        <path>
            <groupId>jakarta.persistence</groupId>
            <artifactId>jakarta.persistence-api</artifactId>
            <version>${jakarta.persistence-api.version}</version>
        </path>
        <path>
            <groupId>com.querydsl</groupId>
            <artifactId>querydsl-apt</artifactId>
            <version>${querydsl.version}</version>
            <classifier>jakarta</classifier>
        </path>
    </annotationProcessorPaths>
</configuration>

refs

clone

#example-querydsl

#Introduction

#`querydsl-maven-plugin`

#`maven-compiler-plugin`