那些遇到过的问题

OpenEntityManagerInViewFilter问题

sau*_*uce 4 spring hibernate spring-mvc

我已经搜索过这个网站,以获得使OpenEntityManagerInViewFilter工作的答案.我有一个标准的User对象,它引用一个具有多对多关系的角色对象作为集合.当我尝试从控制器编辑我的用户时,我得到了可怕的懒惰初始化异常.在大多数情况下,通过简单地将其添加到您的web.xml,这似乎是非常简单的:

<filter>
    <filter-name>oemInViewFilter</filter-name>
    <filter-class>
        org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter
    </filter-class>
</filter>

<filter-mapping>
    <filter-name>oemInViewFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
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现在我尝试过没有成功的事情(这些是来自网络的各种建议)

  1. 将上面的声明移到web.xml的顶部
  2. 围绕我的控制器方法和/或整个类绕过@Transactional
  3. 显然,将获取类型转换为渴望的作品,但在这里打败了我的意图
  4. 玩我在哪里定义了entityManagerFacorty
  5. 已验证OpenEntityManager存在于惰性init异常中,因此将其触发

关于我读过的唯一一件对我有意义的事情就是因为我的持久层设置如何并且过滤器抓错了而我正在加载两个不同的会话.

继承我控制器中的方法,我从数据库中找到一个用户并导致延迟初始化异常,因为它没有从用户对象中检索角色.

@RequestMapping(value = "/edit/{id}", method = RequestMethod.GET)
   public String edit(@PathVariable final Integer id, final ModelMap modelMap)
   {
      final User user = userDao.find(id); ******This causes the lazy init exception

      if (user != null)
      {
         modelMap.addAttribute("userInstance", user);
         modelMap.addAttribute("validRoles",  new HashSet<Role>(roleDao.findAll()));
         return "/user/edit";
      }
      return "redirect:/user/list";
   }
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这是我的相关设置:

web.xml中:

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         id="WebApp_ID" version="2.5">

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/board-servlet.xml  *****This file references the file with entityManager declared*****
            /WEB-INF/board-security.xml
        </param-value>
    </context-param>

    <filter>
        <filter-name>springSecurityFilterChain</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>springSecurityFilterChain</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>board</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>board</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.css</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.js</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.jpg</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.png</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.gif</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.ico</url-pattern>
    </servlet-mapping>

    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

    <filter>
        <filter-name>oemInViewFilter</filter-name>
        <filter-class>
            org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter
        </filter-class>
    </filter>

    <filter-mapping>
        <filter-name>oemInViewFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <filter>
        <filter-name>sitemesh</filter-name>
        <filter-class>
            com.opensymphony.module.sitemesh.filter.PageFilter
        </filter-class>
    </filter>

    <filter-mapping>
        <filter-name>sitemesh</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>
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板servlet.xml中

<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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">

  ****This is what pulls in my entityManager  
 <import resource="classpath:persistence-spring-beans.xml"/> 

    <mvc:annotation-driven/>

    <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="100000"/>
    </bean>

    <bean id="messageSource"
          class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
        <property name="basename" value="classpath:message"/>
        <property name="defaultEncoding" value="UTF-8"/>
    </bean>

</beans>
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持久性的弹簧-beans.xml文件

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
            http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
            http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

    <context:annotation-config/>
    <context:component-scan base-package="com.something" use-default-filters="true"/>
    <aop:aspectj-autoproxy proxy-target-class="true"/>

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

    <bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="entityManagerFactory">
        <property name="persistenceUnitName" value="prodPersistenceUnit"/>
        <property name="dataSource" ref="c3p0PostgresDataSource"/>
        <property name="packagesToScan" value="com.something.persistence.dto"/>
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"/>
        </property>
    </bean>

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

    <bean id="c3p0PostgresDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
        <property name="driverClass" value="org.postgresql.Driver"/>
        <property name="jdbcUrl" value="jdbc:postgresql://localhost:5432/yellow_hammer"/>
        <property name="user" value="yellow"/>
        <property name="password" value="hammer"/>
        <property name="initialPoolSize" value="3"/>
        <property name="minPoolSize" value="3"/>
        <property name="maxPoolSize" value="50"/>
        <property name="idleConnectionTestPeriod" value="200"/>
        <property name="acquireIncrement" value="1"/>
        <property name="maxStatements" value="0"/>
        <!-- 0 means: statement caching is turned off.  -->
        <property name="numHelperThreads" value="3"/>
        <!-- 3 is default -->
    </bean>
</beans>
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如果这还不够相关信息,请告诉我.

编辑 UserDao - 这扩展了GenericDao,我将在下面发布.

@Dao
public class UserDao extends GenericDao<User>
{
   public User findByUsernameAndPassword(final String username, final String password)
   {
      final Query query = entityManager.createQuery("from User user " + "where user.username = :user " + "and user.password = :pass ")
         .setParameter("user", username)
         .setParameter("pass", password);

      return uniqueResult(query);
   }

   public List<User> findByRole(final Role roleIn)
   {
      if (roleIn == null)
      {
         return null;
      }

      final Query query = entityManager.createQuery("select user from User user, Role role where role = :roleParam ").
         setParameter("roleParam", roleIn);

      return query.getResultList();
   }
}
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GenericDao

public class GenericDao<T extends BaseDto>
{
   protected Class<T> entityClass;

   @PersistenceContext
   protected EntityManager entityManager;

   public GenericDao()
   {
      final ParameterizedType genericSuperclass = (ParameterizedType) getClass().getGenericSuperclass();
      this.entityClass = (Class<T>) genericSuperclass.getActualTypeArguments()[0];
   }

   public T find(final Integer id)
   {
      return entityManager.find(entityClass, id);
   }

   public List<T> findAll()
   {
      final Query query = entityManager.createQuery("from " + entityClass.getSimpleName());
      return query.getResultList();
   }

   public T save(final T t)
   {
      if (t != null)
      {
         return t.getId() != null && t.getVersion() != null ? update(t) : create(t);
      }

      return null;
   }

   private T create(final T t)
   {
      entityManager.persist(t);
      return t;
   }

   private T update(final T t)
   {
      return entityManager.merge(t);
   }

   public void delete(T t)
   {
      t = entityManager.merge(t);
      entityManager.remove(t);
   }

   protected T uniqueResult(final Query query)
   {
      final List results = query.getResultList();
      if (results.isEmpty())
      {
         return null;
      }
      else if (results.size() == 1)
      {
         return entityClass.cast(results.get(0));
      }

      // TODO send notification, multiple results found
      return null;
   }
}
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Ral*_*lph 12

但现在!!

让我猜一下:你的申请名称是:董事会？

正确？然后继续阅读剩下的答案!

是的,你有两个实体管理器,甚至两个相同的应用程序上下文(一个应用程序上下文和一个Web上下文) - 所以你有两个每个bean!

发生的事情是:你只有一个(相关的)spring配置文件:'board-servlet.xml'('persistence-spring-beans.xml'包含在该文件中,所以至少它是一个大的逻辑文件)

然后在'web.xml'中从此文件创建两次上下文:

第一:

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>
        /WEB-INF/board-servlet.xml  *****This file references the file with entityManager declared*****
        /WEB-INF/board-security.xml
    </param-value>
</context-param>
...
<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
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ContextLoaderListener加载由"contextConfigLocation"参数中的文件指定的应用程序上下文.

第二:

<servlet>
    <servlet-name>board</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>
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Dispatcher Servlet创建Web应用程序上下文,其中xml文件为:

  • 由init-param"contextConfigLocation"命名
  • 或者,如果没有这样的参数,它会查找名为'/WEB-INF/-servlet.xml'的文件

(有关更多详细信息,请查看FrameworkServlet的Java Doc )

在您的情况下,没有明确命名的文件,因此它再次读取'board-servlet.xml'.

你需要做的是将它们分开:

  • 除去<import resource="classpath:persistence-spring-beans.xml"/>从board-servlet.xml
  • 改变contextConfigLocation的web.xml,它指的是classpath:persistence-spring-beans.xml和/WEB-INF/board-security.xmldirecly
  • (不是100%必要)分离"上下文:组分扫描",使得部件的扫描在board-servlet.xml扫描仅@Controller和在组件扫描persistence-spring-beans.xml的扫描为他人(@Service,@Component,@Repository和@Dao)
  • 最后一步:请告诉我它现在有效

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