OpenSessionInViewFilter 配置解决延迟加载
一、手动加载 如：
Hibernate.initialize(obj.getUser());//加载用户对象
二、使用OpenSessionInViewFilter 配置解决延迟加载 如：
<!--OpenSessionInViewFilter 解决延迟加载问题 -->
<filter>
<filter-name>OpenSessionInViewFilter</filter-name>
<filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter </filter-class>
<!-- singleSession默认为true,若设为false则等于没用OpenSessionInView -->
<init-param>
<param-name>singleSession</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>OpenSessionInViewFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
