如何将使用标准获取的标准数据插入到休眠中的另一个表中

Question

我正在使用休眠条件从数据库中获取数据，现在我想将该数据插入到另一个表中..

这是我的 DAO 类

@SuppressWarnings({ "unchecked", "rawtypes" })
public List<Post> getPostList() throws Exception {
    session = sessionFactory.openSession();
    Criteria cr = session.createCriteria(Post.class).setResultTransformer(Transformers.aliasToBean(Result.class));
    ProjectionList projList = Projections.projectionList();
    projList.add(Projections.sum("val"), "topValue");
    projList.add(Projections.groupProperty("userId"), "uid");
    cr.setProjection(projList);
    List postList = cr.list();
    tx = session.getTransaction();
    session.beginTransaction();
    tx.commit();
    return postList;
}

这是我的帖子类

@Entity
@Table(name="post")
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class Post implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue
@Column(name="id")
private long id;

@Column(name="uid")
private long userId;

@Column(name="value")
private long val;

public long getId() {
    return id;
}

public void setId(long id) {
    this.id = id;
}

public long getUserId() {
    return userId;
}

public void setUserId(long userId) {
    this.userId = userId;
}

public long getVal() {
    return val;
}

public void setVal(long val) {
    this.val = val;
}
}

这是我的控制器

@RequestMapping(value = "/posts", method = RequestMethod.GET)
public @ResponseBody
List<Post> getEmployee() {

    List<Post> postList = null;
    try {
        postList = profileService.getPostList();

    } catch (Exception e) {
        e.printStackTrace();
    }

    return postList;
}

请建议我这样做的正确方法我是休眠新手

Answer 1

您是否尝试过通过@PersistenceContext 将事务留给spring 容器？

public class SampleServiceImpl implements SampleService {

@PersistenceContext(type = PersistenceContextType.TRANSACTION)
protected EntityManager entityManager;

public static final Logger LOG = Logger.getLogger(SampleServiceImpl.class);


@Override
@Transactional
public void retrieveANdSAve(){
  Session session =(Session)entityManager.getDelegate()  ;
  Criteria cr = session.createCriteria(ProductRequest.class);
  List <Product> results = cr.list();
  for(Product pro: results){
    entityManager.merge(whatever object);
  }


}
**Note: u must have properly done your orm/jdbc configurations right i your xml config or Annotation config

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
            <property name="database" value="${hibernate.database}" />
            <property name="showSql" value="${hibernate.showSql}" />
        </bean>
    </property>

    <property name="jpaPropertyMap">
        <map>
            <entry key="hibernate.hbm2ddl.auto" value="update/create" />
            <entry key="hibernate.format_sql" value="true" />
            <entry key="hibernate.show_sql" value="false" />
            <entry key="hibernate.dialect" value="" />

            <!-- Connection pooling -->
            <entry key="hibernate.c3p0.min_size" value="5" />
            <entry key="hibernate.c3p0.max_size" value="20" />
            <entry key="hibernate.c3p0.timeout" value="1800" />
            <entry key="hibernate.c3p0.max_statements" value="50" />
            <entry key="hibernate.jdbc.batch_size" value="100" />

            <!-- Auditing -->
            <!-- entry key="hibernate.ejb.interceptor" value="org.common.hibernate.AuditInterceptor" /> -->

            <!-- Caching -->
            <!--
                <entry key="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider" /> <entry key="hibernate.cache.use_query_cache" value="true" />
            -->
            <!-- Extra debugging -->
            <entry key="hibernate.generate_statistics value" value="true" />
            <entry key="hibernate.cache.use_structured_entries" value="true" />

            <!-- Lucene -->
            <entry key="hibernate.search.default.indexBase" value="${application.dataDir}/lucene" />
            <entry key="hibernate.search.default.directory_provider" value="org.hibernate.search.store.FSDirectoryProvider" />

            <!-- JSR 303 Bean Validation -->
            <entry key="javax.persistence.validation.mode" value="${validation.mode}" />
            <entry key="javax.persistence.validation.group.pre-persist" value="${validation.group.pre-persist}" />
            <entry key="javax.persistence.validation.group.pre-update" value="${validation.group.pre-update}" />
            <entry key="javax.persistence.validation.group.pre-remove" value="${validation.group.pre-remove}" />
        </map>
    </property>
</bean>

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value=" " />
    <property name="url" value=" " />
    <property name="username" value="" />
    <property name="password" value="" />
</bean>

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

<tx:annotation-driven transaction-manager="transactionManager" />