如何使用Spring 3配置JPA？

Question

我一直在阅读spring的文档,但我必须说它有点混乱,给出了如何配置JPA的几个不同选项.

使用弹簧3配置JPA 2(使用休眠)的最佳方法是什么？如果你有一个pom,web.xml,applicationContext.xml和任何需要的java代码的例子,请你也可以发布它.

谢谢!

Answer 1

我使用EclipseLink,但配置必须非常相似.这里有最重要的部分.

pom.xml中:

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>
    <dependency>
        <groupId>org.eclipse.persistence</groupId>
        <artifactId>eclipselink</artifactId>
        <version>2.0.1</version> 
    </dependency>
    <dependency> 
        <groupId>javax.persistence</groupId>
        <artifactId>javax.persistence</artifactId>
        <version>2.0.0</version>
    </dependency>

persistence.xml中:

    <?xml version="1.0" encoding="UTF-8" ?>
    <persistence xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence 
    http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
    version="2.0" xmlns="http://java.sun.com/xml/ns/persistence">

    <persistence-unit name="persistenceUnit" transaction-type="RESOURCE_LOCAL" />

</persistence>

的applicationContext-dao.xml:

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="persistenceXmlLocation" value="classpath:persistence.xml" />
    <property name="persistenceUnitName" value="persistenceUnit" /> 
    <property name="dataSource" ref="dataSource"/>
    <property name="jpaPropertyMap">
        <props>
            <prop key="eclipselink.weaving">false</prop>
        </props>
    </property>
</bean>

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />

User.java:

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    private Integer id;

    private String name;

    // Getters and setters

}

UserDao.java:

@Repository
public class JpaUserDao implements UserDao {

    @PersistenceContext
    private EntityManager em;

    @Override
    public Item get(Integer id) {
        return em.find(User.class, id);
    }
}

UserService.java:

@Service 
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    @Transactional
    @Override
    public User getUser(Integer id) {
        return userDao.get(id);
    }

}

希望能帮助到你.

Answer 2

或者,Spring 3+和JPA 2.0可以在动态代理的帮助下集成.

您可以在此处找到所有文档和下载示例

在这种情况下,具有命名JPA查询的接口用于执行查询.在动态代理的帮助下,接口被视为普通的Spring bean.它们可以以相同的方式注入(或自动装入)任何其他bean.

查询也可以位于单独的orm-mapping.xml文件中,并按域(或在您方便时)拆分.这为持久层提供了高度的灵活性和可维护性.

public interface OrganisationQueries {

        @Query(named = "find.organisation.by.role.id")
        public Organisation findOrganisationByRoleId(Long roleId);

        @Query(named = "find.all.organisations")
        public List<Organisation> findAllOrganisations();
    }
    public class OrganisationServiceImpl implements OrganisationService {
        @PersistenceContext
        private EntityManager em;
        @Autowired
        private OrganisationQueries organisationQueries;
        @Override
        public Organisation findOrganisationByRoleId(Long roleId) {
            return organisationQueries.findOrganisationByRoleId(roleId);
        }
        @Override
        public List<Organisation> findAllOrganisations() {
            return organisationQueries.findAllOrganisations();
        }
    }

   <entity-mappings xmlns="..." version="1.0">
      <named-query name="find.organisation.by.role.id">
          <query><![CDATA[
                    select r.organisation from Role r
                    where r.id =?1
          ]]></query>
      </named-query>
      <named-query name="find.all.organisations">
           <query><![CDATA[
                   select org from Organisation org
                    left join fetch org.organisationType
           ]]></query>
       </named-query>
   </entity-mappings>

Answer 3

我建议你看一下 Spring Roo，它创建了一个 Spring Web 项目以及 pom 和所有需要的配置文件（例如 JPA）。如果您不喜欢 Roo，您可以放弃它并像平常的 Spring Web 应用程序一样威胁该项目。恕我直言，这是获得初始项目设置的最快方法。