Servlet中文问题

String userName = request.getParameter("userName");
得到userName的值是null，怎么解决？

解决方案 »

  1.   

    说明请求中没有userName这个参数,在页面中加上就行了
      

  2.   

    src='sendmessageservlet?userName="+userName+"'
    这个行不行？
      

  3.   

    你不是表单提交吗？？？
    <form。〉
      

  4.   

    out.println("<frameset rows='80%,*'>");
                    out.println("<frame src='topservlet?userName="+userName+"'>");
                    out.println("<frame src='sendmessageservlet?userName="+userName+"'>");
                    out.println("</frameset>");
      

  5.   


    PrintWriter out = response.getWriter();
            request.setCharacterEncoding("GBK");
            response.setCharacterEncoding("GBK");
            String userName = request.getParameter("userName");
    //        userName=new String(userName.getBytes("ISO-8859-1"),"gbk");
            if (userName.equals("") || userName == null) {
                out.println("<font color=red>您未写昵称，请输入昵称后再进入！</font>");
                response.sendRedirect("loginservlet");
            } else {
                ArrayList userList = (ArrayList) getServletContext().getAttribute(
                        "userName");
                if (userList == null) {
                    userList = new ArrayList();
                }
                if (!userList.contains(userName)) {
                    userList.add(userName);
                    HttpSession session = request.getSession();
                    session.setAttribute("userName", userName);
                    System.out.println("MainServlet:"+userName);
                    getServletContext().setAttribute("userName", userList);
                    out.println("<html>");
                    out.println("<head><title>聊天室</title></head>");
                    out.println("<frameset rows='80%,*'>");
                    out.println("<frame src='topservlet?userName="+userName+"'>");
                    out.println("<frame src='sendmessageservlet?userName="+userName+"'>");
                    out.println("</frameset>");
                    out.println("</html>");
                }else{
                    response.sendRedirect("loginservlet");
                }
            }
            out.close();