Hibernate的懒加载session丢失解决方法

在web.xml加入spring提供的过滤器，延长session的生命周期

<!--Hibernate的懒加载session丢失解决方法 -->
    <filter>
        <filter-name>openSessionInView</filter-name>
        <filter-class>org.springframework.orm.hibernate4.support.OpenSessionInViewFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>openSessionInView</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>