使用Maven从现有数据库生成JPA2实体

Question

Generate JPA 2 Entities from existing Database

我想做同样的事情，但使用的是maven build。

请推荐插件。当我用谷歌搜索它时，我发现了使用JPA注释实体的JPA元模型生成。我没有找到任何与这个问题相关的东西。

Answer 1

对于您正在使用的hibernate，默认选项将是hibernate3-maven-plugin，更具体地说，是使用<ejb3>true</ejb3>配置的hibernate3:hbm2java目标。它将生成带注释的org.hibernate.annotations(大多数注释来自标准的pojos包，但也可能包括自定义pojos)。

有关示例配置，请访问JBoss Community查看John Citizen's answer。

Answer 2

你应该试试MinuteProject：(它生成maven项目)

http://minuteproject.wikispaces.com/

http://javacodesamples.wordpress.com/2011/02/04/jpa2-reverse-engineering-tool/

Answer 3

你可以使用hibernate-tools-maven-plugin。为了使用它，您可以使用以下配置：

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <h2.version>1.4.200</h2.version>
    <hibernate-tools-maven-plugin.version>5.4.11.Final</hibernate-tools-maven-plugin.version>
  </properties>
  <build>
    <plugins>
      <plugin>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-tools-maven-plugin</artifactId>
        <version>${hibernate-tools-maven-plugin.version}</version>
        <dependencies>
          <dependency>
            <groupId>jakarta.xml.bind</groupId>
            <artifactId>jakarta.xml.bind-api</artifactId>
            <version>2.3.2</version>
          </dependency>
          <dependency>
            <groupId>org.glassfish.jaxb</groupId>
            <artifactId>jaxb-runtime</artifactId>
            <version>2.3.2</version>
          </dependency>
          <dependency>
            <!-- DB Driver of your choice -->
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>${h2.version}</version>
          </dependency>
        </dependencies>
        <executions>
          <execution>
            <id>Display Help</id>
            <phase>validate</phase>
            <goals>
              <goal>help</goal>
            </goals>
          </execution>
          <execution>
            <id>Entity generation</id>
            <phase>generate-sources</phase>
            <goals>
              <goal>hbm2java</goal>
            </goals>
            <configuration>
              <ejb3>true</ejb3>
              <jdk5>true</jdk5>
            </configuration>
          </execution>
          <execution>
            <id>Schema generation</id>
            <phase>generate-resources</phase>
            <goals>
              <goal>hbm2ddl</goal>
            </goals>
            <configuration>
              <delimiter>;</delimiter>
              <haltOnError>true</haltOnError>
              <format>true</format>
            </configuration>
          </execution>
        </executions>
        <configuration>
          <revengFile>${project.basedir}/src/main/hibernate/hibernate.reveng.xml</revengFile>
          <configFile>${project.basedir}/src/main/hibernate/hibernate.cfg.xml</configFile>
          <detectManyToMany>true</detectManyToMany>
          <detectOneToOne>true</detectOneToOne>
          <detectOptimisticLock>true</detectOptimisticLock>
          <createCollectionForForeignKey>true</createCollectionForForeignKey>
          <createManyToOneForForeignKey>true</createManyToOneForForeignKey>
        </configuration>
      </plugin>
    </plugins>
  </build>

运行mvn generate-resources，您将找到生成的JPA实体和test.mv.db H2-Database的Schema DDL (项目中的根文件夹)。

连接配置位于src/main/hibernate中的hibernate.cfg.xml文件中。在我们的案例中，包含以下内容：

<?xml version = "1.0" encoding = "utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM
  "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <property name="hibernate.dialect">org.hibernate.dialect.H2Dialect</property>
    <property name="hibernate.connection.driver_class">org.h2.Driver</property>
    <property name="hibernate.connection.url">jdbc:h2:./test;DB_CLOSE_ON_EXIT=FALSE</property>
    <property name="hibernate.connection.username">sa</property>
    <property name="hibernate.connection.password"></property>
    <property name="hibernate.connection.pool_size">1</property>
    <property name="hibernate.show_sql">true</property>
  </session-factory>
</hibernate-configuration>

我们使用hibernate.reveng.xml文件来自定义映射类型配置，例如，为了使用我们可以使用的java.time类型：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-reverse-engineering SYSTEM
  "http://hibernate.org/dtd/hibernate-reverse-engineering-3.0.dtd" >

<hibernate-reverse-engineering>

  <type-mapping>
    <sql-type jdbc-type="DATE" hibernate-type="java.time.LocalDate"/>
    <sql-type jdbc-type="TIMESTAMP" hibernate-type="java.time.LocalDateTime"/>
  </type-mapping>

</hibernate-reverse-engineering>

完整的项目可以在Github上找到。