Hibernate，Spring，Struts2：以視圖模式打開會話

Question

我正在使用Hibernate進行持久化而使用Struts2作為視圖模式的項目。 我的配置文件是：

web.xml

 <web-app>
     //......
     //.....
     <filter>
        <filter-name>struts2</filter-name>
        <filter-class>
          org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
        </filter-class>
      </filter>
      <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
      </filter-mapping>

      <!-- The defintion of the root Spring Container shared by all Servlets and Filters -->
      <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
      </context-param>
      <!-- Creates the spring Container shared by all servlet and filters -->
      <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
      </listener>

       <filter> <!-- Get spring to keep the session open for the whole request, so hibernate's lazy loads work -->
        <filter-name>openSessionInViewFilter</filter-name>
        <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
      </filter>
      <filter-mapping>
        <filter-name>openSessionInViewFilter</filter-name>
        <url-pattern>/*</url-pattern> 
      </filter-mapping>
    </web-app>

---

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans >
//.......
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/DB_TEST"></property>
        <property name="username" value="root"></property>
        <property name="password" value=""></property>
    </bean>

    <bean id="persistenceUnitManager" class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
        <property name="persistenceXmlLocations">
            <list>
                <value>classpath*:META-INF/persistence.xml</value>
            </list>
        </property>
        <property name="defaultDataSource" ref="dataSource"></property>
    </bean>

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

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

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

---

我的問題是我無法在Struts2的視圖模式下保持Hibernate會話打開，這意味着當我嘗試加載一些尚未使用Hibernate初始化的數據時（例如，像集合），我得到了org.hibernate.LazyInitializationException ，因此通過進行一些研究，我發現必須在web.xml中添加此范圍，以使會話在視圖模式下保持打開狀態。

范圍

<filter> <!-- Get spring to keep the session open for the whole request, so hibernate's lazy loads work -->
    <filter-name>openSessionInViewFilter</filter-name>
    <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>openSessionInViewFilter</filter-name>
    <url-pattern>/*</url-pattern> 
  </filter-mapping>

---

但是即使這樣我仍然有同樣的問題，所以誰能告訴我我在做什么錯。

Answer 1

過濾器鏈的順序很重要。 在您的情況下，應在Struts執行動作之前打開會話，然后在Strut執行動作之前關閉會話。 最后一件事是在春季通過管理Hibernate會話完成。 因此，對過濾器重新排序，並允許struts2調度程序接受來自第一個過濾器的請求。

   <filter> <!-- Get spring to keep the session open for the whole request, so hibernate's lazy loads work -->
    <filter-name>openSessionInViewFilter</filter-name>
    <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>openSessionInViewFilter</filter-name>
    <url-pattern>/*</url-pattern> 
  </filter-mapping>

 <filter>
    <filter-name>struts2</filter-name>
    <filter-class>
      org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
    </filter-class>
  </filter>
  <filter-mapping>
    <filter-name>struts2</filter-name>
    <url-pattern>/*</url-pattern>
    <dispatcher>REQUEST</dispatcher>
    <dispatcher>FORWARD</dispatcher>
  </filter-mapping>

Answer 2

我前段時間遇到過類似的問題，為了解決此問題，我使用了hibernate.enable_lazy_load_no_trans屬性而不是OpenSessionInView模式。 有關LazyInitializationException的更多信息，請在此處或此處找到