I just introduced hibernate to my new project using spring + hibernate + dwr,

All the hibernate configuration are done in the dispatcher-servlet.xml (transaction etc..),

my project lay out look like this

DwrLayer --> FacadeLayer --> Servicelayer --> DaoLayer

In the above four java class , transaction applied in FacadeLayer, so if i select some data from table with lazy loading is true, i can access all fields from FacadeLayer or Servicelayer or DaoLayer with out any lazy loading errors,
But if i returned data from DwrLayer, then the lazy -true object will thrown errors, So i force to do, that setting all unwanted lazy-true object as null with in FacadeLayer before return.

Is there is any way to do it safely withg out setting object as null ?

Thanks in advance

Hi,

This is because tyou are trying to access the collection object outside the scope of the session you created.The collection object hasn't been initialised as you require it only when you access it from you rdwr layer.You close the session in your facade layer and then access it from dwr layer which is out of your Hibernate session scope.This problem can be resolved by using "OpenSessionInView"Interceptor.

There are two ways to resolve your issue keeping lazy="true" as it is.

1)In your dispatcher-servlet.xml add the following entry

<bean id="openSessionInViewInterceptor"
class="org.springframework.orm.hibernate3.support.OpenSessionInViewInterceptor">

and the refer this interceptor in your handler mapping.Let say you are using SimpleHandlerMapping then you can inject it as shown below.

<bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
<property name="interceptors">
<list>
<ref bean="openSessionInViewInterceptor"/>
</list>
</property>
<property name="mappings">
<props>
<prop key="/login.do">logginController</prop>
</props>


OR

2) Add the following in your web.xml where servlet-name should be the same name you gave it for your Dispatcher servlet.

<filter>
<filter-name>openSessionInViewFilter</filter-name>
<filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>openSessionInViewFilter</filter-name>
<servlet-name>action</servlet-name>
</filter-mapping>


kartik