DWR 获取request 错误
JS调用类方法：
UserSvlt.UserMessageAdd();

Java类方法：

	public void UserMessageAdd(HttpSession session)

	throws ServletException, IOException

	{

		System.out.println("Test 测试，添加函数进入成功");

		

	//	List<UserInfo> result = new ArrayList<UserInfo>();

		

		sqlBean db= new sqlBean();

		ResultSet rs = null;

		

//		HttpServletRequest request = getRequest();

		HttpServletRequest request = WebContextFactory.get().getHttpServletRequest();

		if(request == null)

		{

			System.out.println("Request Is Null From:UserMessageAdd");

			return ;

		}

		

		

		String strUserID =  new String(request.getParameter("UserID").getBytes("ISO8859_1"),"UTF-8");

		String strMessage =  new String(request.getParameter("message").getBytes("ISO8859_1"),"UTF-8");

		String strIP =  new String(request.getParameter("ip").getBytes("ISO8859_1"),"UTF-8");

当执行到：
String strUserID =  new String(request.getParameter("UserID").getBytes("ISO8859_1"),"UTF-8");
这句的时候，出现错误：

127.0.0.1

2013-9-27 11:49:33 org.directwebremoting.util.CommonsLoggingOutput info

信息: Exec: UserSvlt.UserMessageAdd()

Test 测试，添加函数进入成功

2013-9-27 11:49:33 org.directwebremoting.util.CommonsLoggingOutput warn

警告: Method execution failed: 

java.lang.NullPointerException

	at common.UserSvlt.UserMessageAdd(UserSvlt.java:169)

	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

	at java.lang.reflect.Method.invoke(Method.java:597)

	at org.directwebremoting.impl.ExecuteAjaxFilter.doFilter(ExecuteAjaxFilter.java:34)

	at org.directwebremoting.impl.DefaultRemoter$1.doFilter(DefaultRemoter.java:428)

	at org.directwebremoting.impl.DefaultRemoter.execute(DefaultRemoter.java:431)

	at org.directwebremoting.impl.DefaultRemoter.execute(DefaultRemoter.java:283)

	at org.directwebremoting.servlet.PlainCallHandler.handle(PlainCallHandler.java:52)

	at org.directwebremoting.servlet.UrlProcessor.handle(UrlProcessor.java:101)

	at org.directwebremoting.servlet.DwrServlet.doPost(DwrServlet.java:146)

	at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)

	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)

	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)

	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)

	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)

	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)

	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)

	at