Invalid character in input这是在那么回事啊，急切啊，高手请进

Question

<%@ page contentType="text/html;charset=gb2312"%>
<%@page import="java.sql.*"%>
<%@page import="java.util.*"%>
<jsp:useBean id="reg" scope="page" class="sql_data.sql_data" />
 <%
       String date=new java.util.Date().toString();
       String userid=(String)request.getParameter("userid");
       String password=(String)request.getParameter("password");
　     String cwords=(String)request.getParameter("cwords");
       byte[] tmpbyte=cwords.getBytes("ISO8859_1");
       cwords=new String(tmpbyte);
        String selected=(String)request.getParameter("select");
        byte[] tmpbyte1=selected.getBytes("ISO8859_1");
        selected=new String(tmpbyte1);  
        String sql="select * from userinfo where userid='"+userid+"' and password='"+password+"' ";
        ResultSet rs=reg.executeQuery(sql);
if (rs.next())
{
rs.close();
%>
<SCRIPT language=JavaScript>
alert("帐号或密码错误，请重新输入!");
self.location="guesthome.jsp";
</SCRIPT>
<%}
else
{
      String realname=rs.getString("realname");
      String  email=rs.getString("email");
      String  address=rs.getString("address");
       String str ="INSERT INTO liuyan(userid,realname,email,address,date,sex,cwords) VALUES('"+userid+"','"+realname+"','"+email+"','"+address+"','"+date+"','"+selected+"','"+cwords+"')";
       reg.executeUpdate(str);
      response.sendRedirect("index.jsp");}
%>

Answer 1

错误如下：org.apache.jasper.JasperException: Unable to compile class for JSPAn error occured between lines: 7 and 23 in the jsp file: /web/liuyan/leave.jspGenerated servlet error:
D:\Apache Tomcat\work\localhost\_\web\liuyan\leave$jsp.java:104: Invalid character in input.
                　     String cwords=(String)request.getParameter("cwords");
                ^
1 error

Answer 2

将出错那行删了重写，或者将我下面的拷过去
String cwords=(String)request.getParameter("cwords");
代码没有错，估计是有隐藏的无效字符
另外，从request的到的就是String类型，不需要强制转换

Answer 3

freefalcon(心宇)大哥：按照你说的好用了，可是又出现以下错误，请指教，谢谢 
javax.servlet.ServletException: [Microsoft][ODBC 驱动程序 管理器] 非法的游标状态

Answer 4

你的程序写反了
if (!rs.next()) //加上!
{
rs.close();//不管哪种情况，最后都应关闭rs以及stmt,conn
%>
<SCRIPT language=JavaScript>
alert("帐号或密码错误，请重新输入!");
self.location="guesthome.jsp";
</SCRIPT>
<%}
else
{
      String realname=rs.getString("realname");
      String  email=rs.getString("email");
      String  address=rs.getString("address");
       String str ="INSERT INTO liuyan(userid,realname,email,address,date,sex,cwords) VALUES('"+userid+"','"+realname+"','"+email+"','"+address+"','"+date+"','"+selected+"','"+cwords+"')";
       reg.executeUpdate(str);
      response.sendRedirect("index.jsp");}%>