解决JPA延迟加载错误问题

一：(Spring + Struts + JPA)解决办法

在entity中的@OneToMany、@OneToOne等中设置fetch = FetchType.LAZY 时，在Struts2的Action中进行相关操作出现错误信息如下
org.hibernate.LazyInitializationException异常

解决方法：

在web.xml中加入以下代码：注意必须Struts配置文件的书写顺序 ，必须放到FIlterDispatcher之前

<filter>
<filter-name>jpaFilter</filter-name>
<filter-class>
org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter
</filter-class>
</filter>
<filter-mapping>
<filter-name>jpaFilter</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping>

二：SpringMVC +JPA防止延迟加载错误的解决办法:

配置文件如下

<bean name="openEntityManagerInViewInterceptor"
class="org.springframework.orm.jpa.support.OpenEntityManagerInViewInterceptor">
<property name="entityManagerFactory">
<ref bean="entityManagerFactory"/>
<property>
</bean>

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

<bean id="simpleUrlHandlerMapping"
class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping" >
<property name ="interceptors">
<list>
<ref bean ="openEntityManagerInViewInterceptor"  />
</list>
</property>
<property name ="mappings">
<props>
<prop key="hello.html"> helloController </prop>
<prop key="login.html" > loginAction </prop>
<prop key="userManager.html" > userController </prop>
<prop key="userList.html" > userListController </prop >
</props>
</property>
</bean>