// 得到WebContext对象
  WebContext webcontext = WebContextFactory.get();
 webcontext.getHttpServletRequest(); //得到Request对象
 webcontext.getHttpServletResponse();//得到Response对象
 webcontext.getSession();得到Session对象

在WEB.xml中配置

 <servlet>
  <servlet-name>dwr-invoker</servlet-name>
  <servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class>
  <init-param>
   <param-name>debug</param-name>
   <param-value>true</param-value> //是否打开degug调式..true打开
  </init-param>
  <init-param>
   <param-name>config-Article</param-name>
   <param-value>
    /WEB-INF/classes/dwr/Session.xml //指定dwr的配置文件
   </param-value>
  </init-param>
 </servlet>

 <servlet-mapping>
  <servlet-name>dwr-invoker</servlet-name>
  <url-pattern>/dwr/*</url-pattern>
 </servlet-mapping>

Session.xml的配置
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://www.getahead.ltd.uk/dwr/dwr20.dtd">
<dwr>
 <allow>
  <create creator="spring" javascript="Session"> //由Spring来管理
   <param name="beanName" value="sessionHandler"></param>//value=Spring配置的ID
   <include method="getCurrentBean"/> //暴露的方法
   <include method="checkAccountSession"/>//
  </create>
 </allow>
</dwr>