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JPADatabase: Code generation from entities
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
Many jOOQ users use jOOQ as a complementary SQL API in applications that mostly use JPA for their database interactions, e.g. to perform reporting, batch processing, analytics, etc.
In such a setup, you might have a pre-existing schema implemented using JPA-annotated entities. Your real database schema might not be accessible while developing, or it is not a first-class citizen in your application (i.e. you follow a Java-first approach). This section explains how you can generate jOOQ classes from such a JPA model. Consider this model:
@Entity
@Table(name = "author")
public class Author {
@Id
int id;
@Column(name = "first_name")
String firstName;
@Column(name = "last_name")
String lastName;
@OneToMany(mappedBy = "author")
Set<Book> books;
// Getters and setters...
}
@Entity
@Table(name = "book")
public class Book {
@Id
public int id;
@Column(name = "title")
public String title;
@ManyToOne
public Author author;
// Getters and setters...
}
Now, instead of connecting the jOOQ code generator to a database that holds a representation of the above schema, you can use jOOQ's JPADatabase and feed that to the code generator. The JPADatabase uses Hibernate internally, to generate an in-memory H2 database from your entities, and reverse-engineers that again back to jOOQ classes.
The easiest way forward is to use Maven in order to include the jooq-meta-extensions-hibernate library (which then includes the H2 and Hibernate dependencies)
<dependency>
<!-- Use org.jooq for the Open Source Edition
org.jooq.pro for commercial editions with Java 11 support,
org.jooq.pro-java-8 for commercial editions with Java 8 support,
org.jooq.pro-java-6 for commercial editions with Java 6 support,
org.jooq.trial for the free trial edition with Java 11 support,
org.jooq.trial-java-8 for the free trial edition with Java 8 support,
org.jooq.trial-java-6 for the free trial edition with Java 6 support
Note: Only the Open Source Edition is hosted on Maven Central.
Install the others locally using the provided scripts, or access them from here: https://repo.jooq.org
See the JDK version support matrix here: https://www.jooq.org/download/support-matrix-jdk -->
<groupId>org.jooq</groupId>
<!-- The artifactId has been renamed to jooq-meta-extensions-hibernate in jOOQ 3.14 -->
<artifactId>jooq-meta-extensions</artifactId>
<version>3.11.12</version>
</dependency>
dependencies {
// Use org.jooq for the Open Source Edition
// org.jooq.pro for commercial editions with Java 17 support,
// org.jooq.pro-java-8 for commercial editions with Java 8 support,
// org.jooq.pro-java-6 for commercial editions with Java 6 support,
// org.jooq.trial for the free trial edition with Java 17 support,
// org.jooq.trial-java-8 for the free trial edition with Java 8 support,
// org.jooq.trial-java-6 for the free trial edition with Java 6 support
//
// Note: Only the Open Source Edition is hosted on Maven Central.
// Install the others locally using the provided scripts, or access them from here: https://repo.jooq.org
// See the JDK version support matrix here: https://www.jooq.org/download/support-matrix-jdk
implementation("org.jooq:jooq-meta-extensions-hibernate:3.11.12")
}
dependencies {
// Use org.jooq for the Open Source Edition
// org.jooq.pro for commercial editions with Java 17 support,
// org.jooq.pro-java-8 for commercial editions with Java 8 support,
// org.jooq.pro-java-6 for commercial editions with Java 6 support,
// org.jooq.trial for the free trial edition with Java 17 support,
// org.jooq.trial-java-8 for the free trial edition with Java 8 support,
// org.jooq.trial-java-6 for the free trial edition with Java 6 support
//
// Note: Only the Open Source Edition is hosted on Maven Central.
// Install the others locally using the provided scripts, or access them from here: https://repo.jooq.org
// See the JDK version support matrix here: https://www.jooq.org/download/support-matrix-jdk
implementation "org.jooq:jooq-meta-extensions-hibernate:3.11.12"
}
With that dependency in place, you can now specify the JPADatabase in your code generator configuration:
<configuration>
<generator>
<database>
<name>org.jooq.meta.extensions.jpa.JPADatabase</name>
<properties>
<!-- A comma separated list of Java packages, that contain your entities -->
<property>
<key>packages</key>
<value>com.example.entities</value>
</property>
<!-- Whether JPA 2.1 AttributeConverters should be auto-mapped to jOOQ Converters.
Custom <forcedType/> configurations will have a higher priority than these auto-mapped converters.
This defaults to true. -->
<property>
<key>useAttributeConverters</key>
<value>true</value>
</property>
</properties>
</database>
</generator>
</configuration>
See the configuration XSD, standalone code generation, and maven code generation for more details.
new org.jooq.meta.jaxb.Configuration()
.withGenerator(new Generator()
.withDatabase(new Database()
.withName("org.jooq.meta.extensions.jpa.JPADatabase")
.withProperties(
// A comma separated list of Java packages, that contain your entities
new Property()
.withKey("packages")
.withValue("com.example.entities"),
// Whether JPA 2.1 AttributeConverters should be auto-mapped to jOOQ Converters.
// Custom <forcedType/> configurations will have a higher priority than these auto-mapped converters.
// This defaults to true.
new Property()
.withKey("useAttributeConverters")
.withValue(true)
)
)
)
See the configuration XSD and programmatic code generation for more details.
// The jOOQ-codegen-gradle plugin has been introduced in version 3.19 only.
// The jOOQ-codegen-gradle plugin has been introduced in version 3.19 only.
generationTool {
generator {
database {
name = "org.jooq.meta.extensions.jpa.JPADatabase"
properties {
// A comma separated list of Java packages, that contain your entities
property {
key = "packages"
value = "com.example.entities"
}
// Whether JPA 2.1 AttributeConverters should be auto-mapped to jOOQ Converters.
// Custom <forcedType/> configurations will have a higher priority than these auto-mapped converters.
// This defaults to true.
property {
key = "useAttributeConverters"
value = true
}
}
}
}
}
See the configuration XSD and gradle code generation for more details.
The above will generate all jOOQ artefacts for your AUTHOR and BOOK tables.
How to organise your dependencies
The JPADatabase will use Spring to look up your annotated entities from the classpath. This means that you have to create several modules with a dependency graph that looks like this:
+-------------------+
| Your JPA entities |
+-------------------+
^ ^
depends on | | depends on
| |
+---------------------+ +---------------------+
| jOOQ codegen plugin | | Your application |
+---------------------+ +---------------------+
| |
generates | | depends on
v v
+-------------------------+
| jOOQ generated classes |
+-------------------------+
You cannot put your JPA entities in the same module as the one that runs the jOOQ code generator. See also code generator dependencies.
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