我得到这个错误时,试图调用“持久”方法来保存实体模型到数据库在我的Spring MVC web应用程序。在互联网上找不到任何与这个特定错误有关的帖子或页面。似乎EntityManagerFactory bean有问题,但我对Spring编程相当陌生,所以对我来说,似乎一切都初始化得很好,根据各种教程文章在web。

dispatcher-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
 xmlns:context="http://www.springframework.org/schema/context"
 xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xsi:schemaLocation="
 http://www.springframework.org/schema/mvc 
 http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
 http://www.springframework.org/schema/beans 
 http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
 http://www.springframework.org/schema/context 
  http://www.springframework.org/schema/context/spring-context-4.0.xsd
  http://www.springframework.org/schema/jdbc
  http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
  http://www.springframework.org/schema/data/jpa
  http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
  http://www.springframework.org/schema/data/repository
  http://www.springframework.org/schema/data/repository/spring-repository-1.5.xsd
  http://www.springframework.org/schema/jee
  http://www.springframework.org/schema/jee/spring-jee-3.2.xsd">

    <context:component-scan base-package="wymysl.Controllers" />
    <jpa:repositories base-package="wymysl.repositories"/> 
    <context:component-scan base-package="wymysl.beans" /> 
    <context:component-scan base-package="wymysl.Validators" /> 
    <bean
     class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
     <bean class="org.springframework.orm.hibernate4.HibernateExceptionTranslator"/>

     <bean id="passwordValidator" class="wymysl.Validators.PasswordValidator"></bean>

     <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" />
        <property name="url" value="jdbc:oracle:thin:@localhost:1521:xe" />
        <property name="username" value="system" />
        <property name="password" value="polskabieda1" />
    </bean>

 <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="persistenceXmlLocation" value="classpath:./META-INF/persistence.xml" />
    <property name="dataSource" ref="dataSource" />

    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
            <property name="databasePlatform" value="org.hibernate.dialect.H2Dialect" />
            <property name="showSql" value="true" />
            <property name="generateDdl" value="false" />
        </bean>
    </property>
    <property name="jpaProperties">
        <props>
            <prop key="hibernate.max_fetch_depth">3</prop>
            <prop key="hibernate.jdbc.fetch_size">50</prop>
            <prop key="hibernate.jdbc.batch_size">10</prop>
        </props>
    </property>
</bean>

    <mvc:annotation-driven />

    <bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
    <property name="basename" value="classpath:messages" />
</bean>

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


    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix">
        <value>/WEB-INF/jsp/</value>
    </property>
    <property name="suffix">
        <value>.jsp</value>
    </property>
</bean>

    <mvc:resources mapping="/resources/**" location="/resources/" />
    <mvc:resources mapping="/resources/*" location="/resources/css/"  
    cache-period="31556926"/>



</beans>

RegisterController.java

@Controller
public class RegisterController {

    @PersistenceContext
    EntityManager entityManager;

    @Autowired
    PasswordValidator passwordValidator;

    @InitBinder
    private void initBinder(WebDataBinder binder) {
        binder.setValidator(passwordValidator);
    }

    @RequestMapping(value = "/addUser", method = RequestMethod.GET)
    public String register(Person person) {


        return "register";

    }

    @RequestMapping(value = "/addUser", method = RequestMethod.POST)
    public String register(@ModelAttribute("person") @Valid @Validated Person person, BindingResult result) {
        if(result.hasErrors()) {
            return "register";
        } else {
            entityManager.persist(person);
            return "index";

        }




    }

当前回答

这就像你在使用共享的EntityManager,当你让它自动连接时,为了持久化spring告诉这个EntityManager bean是一个共享bean,为了持久化它需要持有这个bean,直到数据持久化没有完成,因此我们必须使用@Transactional,这样它就会在事务中启动并提交持久化,这样数据或操作就会完全保存或完全回滚。

其他回答

我遇到了同样的问题,我将该方法注释为@Transactional,它工作了。

更新:检查spring文档,默认情况下PersistenceContext是事务类型的,所以这就是为什么方法必须是事务性的(http://docs.spring.io/spring/docs/current/spring-framework-reference/html/orm.html):

The @PersistenceContext annotation has an optional attribute type, which defaults to PersistenceContextType.TRANSACTION. This default is what you need to receive a shared EntityManager proxy. The alternative, PersistenceContextType.EXTENDED, is a completely different affair: This results in a so-called extended EntityManager, which is not thread-safe and hence must not be used in a concurrently accessed component such as a Spring-managed singleton bean. Extended EntityManagers are only supposed to be used in stateful components that, for example, reside in a session, with the lifecycle of the EntityManager not tied to a current transaction but rather being completely up to the application.

当我从Junit测试用例中执行Spring JPA deleteAll()方法时,我得到了相同的错误。我简单地使用了deleteInBatch() & deleteAllInBatch(),它完美地工作。我们不需要在测试用例级别标记@Transactional。

当我在错误的方法/动作级别上使用@Transaction时,我有相同的错误代码。

methodWithANumberOfDatabaseActions() { 
   methodA( ...)
   methodA( ...)
}

@Transactional
void methodA( ...) {
  ... ERROR message
}

当然,我必须将@Transactional放在methodWithANumberOfDatabaseActions()方法的上方。

在我的例子中,这解决了错误消息。

如果没有@Transactional注释,您可以通过从DB中查找实体,然后从DB中删除该实体来实现相同的目标。

CrudRepositor -> void delete(T var1);

这个错误骗了我三天,我面对的情况导致了同样的错误。按照我能找到的所有建议,我尝试了一下这个配置,但没有用。

最终我找到了,不同的是,我正在执行的服务包含在一个普通的jar中,问题是AspectJ没有以相同的方式处理服务实例化。实际上,代理只是简单地调用底层方法,而没有在方法调用之前执行所有正常的Spring魔法。

最后,按照示例放置在服务上的@Scope注释解决了这个问题:

@Service
@Scope(proxyMode = ScopedProxyMode.INTERFACES)
@Transactional
public class CoreServiceImpl implements CoreService {
    @PersistenceContext
    protected EntityManager entityManager;

    @Override
    public final <T extends AbstractEntity> int deleteAll(Class<T> clazz) {
        CriteriaDelete<T> criteriaDelete = entityManager.getCriteriaBuilder().createCriteriaDelete(clazz);
        criteriaDelete.from(clazz);
        return entityManager.createQuery(criteriaDelete).executeUpdate();
    }

}

我发布的方法是一个删除方法,但是注释以同样的方式影响所有持久性方法。

我希望这篇文章能帮助那些在从jar中加载服务时遇到同样问题的人