Dwr的ScriptSessionListener使用，监听ScriptSessionListener的产生，消亡（1）
由于时间紧迫，本人只记录关键部分代码，不明白的可以询问,例子封装的不是很好，只代表明白意思即可，
?标注红色的要注意
dwr.xml
?
<dwr>
? <allow>
??? <create creator="new" javascript="UserService">
????? <param name="class" value="com.huawei.service.UserService"/>
??? </create>
??? <convert converter="bean" match="com.huawei.model.User"/>
? </allow>
</dwr>
------------------------------------------------------------
web.xml
<listener>
??<listener-class>com.huawei.listener.AddScriptSessionListener</listener-class>
?</listener>
?<servlet>
??<servlet-name>dwr-invoker</servlet-name>
??<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
??<!--
??<init-param>
???<param-name>debug</param-name>
???<param-value>true</param-value>
??</init-param>
?? -->
??<init-param>
???<param-name>activeReverseAjaxEnabled</param-name>
???<param-value>true</param-value>
??</init-param>
??<init-param>
???<param-name>org.directwebremoting.event.ScriptSessionListener</param-name>
???<param-value>com.huawei.listener.AddScriptSessionListener</param-value>
??</init-param>
??<load-on-startup>3</load-on-startup>
?</servlet>
?<servlet-mapping>
??<servlet-name>dwr-invoker</servlet-name>
??<url-pattern>/dwr/*</url-pattern>
?</servlet-mapping>
?
