java EntityManager 不能使用持久化将元素保存到数据库
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EntityManager cannot use persist to save element to database
提问by Qingshan Zhang
I met the problem of persisting element to database using EntityManager. Based on the answers I found, I tried those 4 ways in my DaoJpa to do such thing but still failed. Here I attached the four ways I tried:
我遇到了使用 EntityManager 将元素持久化到数据库的问题。根据我找到的答案，我在 DaoJpa 中尝试了这 4 种方法来做这样的事情，但仍然失败。在这里我附上了我尝试过的四种方法：
Code in Controller part:
控制器部分的代码：
@Transactional
SmartProduct smartProduct = new SmartProduct();
smartProduct.setName("Dove Soap");
smartProductDao.persist(smartProduct);
1. DaoJpa:
1. 道帕：
@Transactional
public void persist(SmartProduct smartProduct) {
entityManager.persist(smartProduct);
Doesn't work!
不起作用！
2.
2.
@Transactional
public void persist(SmartProduct smartProduct) {
entityManager.persist(smartProduct);
entityManager.flush();
Exception I got: no transaction is in progress
我得到的例外：没有正在进行的交易
3.
3.
@Transactional
public void persist(SmartProduct smartProduct) {
EntityTransaction emTransaction = entityManager.getTransaction();
emTransaction.begin();
entityManager.persist(smartProduct);
emTransaction.commit();
entityManager.close();
Exception I got: Not allowed to create transaction on shared EntityManager - use Spring transactions or EJB CMT instead
我得到的例外：不允许在共享 EntityManager 上创建事务 - 改用 Spring 事务或 EJB CMT
4.
4.
@Transactional
public void persist(SmartProduct smartProduct) {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("persistenceUnit");
EntityManager em = emf.createEntityManager();
EntityTransaction etx = em.getTransaction();
etx.begin();
em.persist(smartProduct);
etx.commit();
em.close();
emf.close();
Exception I got: The application must supply JDBC connections
我得到的例外：应用程序必须提供 JDBC 连接
Could someone help me figure out the problem please? Many thanks in advance!
有人可以帮我找出问题吗？提前谢谢了！
Many thanks JustinKSU's help. I add the annotation in Spring context and then it solved! Here is the previous version of my Spring context:
非常感谢 JustinKSU 的帮助。我在 Spring 上下文中添加了注释，然后就解决了！这是我的 Spring 上下文的先前版本：
<bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<tx:annotation-driven mode="aspectj" transaction-manager="transactionManager" />
<bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="entityManagerFactory">
<property name="persistenceUnitName" value="persistenceUnit" />
<property name="dataSource" ref="dataSource" />
</bean>
After added the
添加后
<tx:annotation-driven />
it works:
有用：
<tx:annotation-driven />
<bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<tx:annotation-driven mode="aspectj" transaction-manager="transactionManager" />
<bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="entityManagerFactory">
<property name="persistenceUnitName" value="persistenceUnit" />
<property name="dataSource" ref="dataSource" />
</bean>
回答by JustinKSU
To enable @Transactional in your Spring context you should have the following:
要在 Spring 上下文中启用 @Transactional，您应该具备以下条件：
Appropriate for your version of Spring:
适用于您的 Spring 版本：
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">
Enable the annotations:
启用注释：
<tx:annotation-driven />
Declare your transaction manager injecting your entity manager:
声明您的事务管理器注入您的实体管理器：
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
回答by Criss
If you still have this problem and all the configurations are ok, please make sure that the @Transaction annotated method is public, not protected in order to be identified/managed by the transaction manager.
如果还是有这个问题，并且所有的配置都OK，请确保@Transaction注解的方法是public的，没有protected，以便事务管理器识别/管理。
