Wednesday, December 28, 2011

Open Session In View Filter Usage

Open Session In View Filter of Spring framework takes care of hibernate session management of a web application.  The integration of it is done at the web.xml.

Firstly, the spring beans ought to be loaded to the application context. This is done with a 'context-param' element. Secondly, define a filter with a 'filter' element (here my filter class is com.shyarmal.filter.MyOpenSessionInViewFilter which extends org.springframework.orm.hibernate3.support.OpenSessionInViewFilter).  Thirdly, define a filter mapping to the filter appropriately using 'filter-mapping' element. Notice the init parameter (sessionFactoryBeanName) passed to the filter. It is the id of the session factory defined in spring beans xml configurations.

web.xml elements of interest are as follows.
===================================================================
<context-param>
   <param-name>contextConfigLocation</param-name>
   <param-value>/WEB-INF/springmvc-servlet.xml</param-value>
</context-param>

<filter>
   <filter-name>openSessionInViewFilter</filter-name>
   <filter-class>com.shyarmal.filter.MyOpenSessionInViewFilter</filter-class>
   <init-param>
        <param-name>sessionFactoryBeanName</param-name>
        <param-value>sessionFactory</param-value>
   </init-param>
</filter>

<filter-mapping>
        <filter-name>openSessionInViewFilter</filter-name>
        <url-pattern>/*</url-pattern>
</filter-mapping>
===================================================================

Following are the spring bean definitions related to session factory used for the integration of open session in view filter.
===================================================================

<bean id="hibernateConfigProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
   <property name="location">
       <value>classpath:hibernate.properties</value>
   </property>
</bean>

<bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource">
   <property name="driverClassName" value="${jdbc.driver.class.name}"/>
   <property name="url" value="${jdbc.url}"/>
   <property name="username" value="${jdbc.username}"/>
   <property name="password" value="${jdbc.password}"/>
</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="mappingResources">
        <list>
            <value>Accounts.hbm.xml</value>
             .....
            .....
            .....
        </list>
    </property>
    <property name="hibernateProperties" ref="hibernateConfigProperties"/>
</bean>

===================================================================

thanks,
Shyarmal.

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