紧急求助org.apache.jasper.JasperException: java.lang.Integer

代码如下：<%@ page import="java.sql.*"
contentType="text/html;charset=gb2312"%><html>
<head><title>用户登录信息检测</title></head>
<body>
<%
       String username=new String(request.getParameter("username").getBytes("ISO8859_1"),"GBK");
       String password=new String(request.getParameter("password").getBytes("ISO8859_1"),"GBK");
        int isvalid,isadmin,uid;
        String uname,sql; 
        
         String users="sa";
         String pwd="sa";
         Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
         String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=bbs"; //bbs　为你的数据库的       
         Connection conn=DriverManager.getConnection(url,users,pwd);
         Statement stmt=conn.createStatement();
         sql="SELECT * FROM Users WHERE UserName='"+username+"'AND PassWord='"+password+"'";
         ResultSet rs=stmt.executeQuery(sql);
         if(rs.next())
         
         {
            uname=rs.getString("UserName");
            uid= rs.getInt("ID");
            isadmin=rs.getInt("IsAdmin");
            isvalid=rs.getInt("IsValid");
            
          //uid=Integer.parseInt(rs.getString("ID").toString());
           //isadmin=rs.getInt("IsAdmin");       
           //isvalid=rs.getInt("IsValid");
          // isadmin=Integer.parseInt(rs.getString("IsAdmin").toString());
          // isvalid=Integer.parseInt(rs.getString("IsValid").toString());
           
           
           if(isadmin==1&&isvalid==1)
           {
             session.setAttribute("current_id",uid);
             session.setAttribute("current_name",uname);
             response.sendRedirect("/bbs/manage.jsp");  
           }
            if(isadmin==0&&isvalid==1)
           {
              session.setAttribute("current_id",uid);
              session.setAttribute("current_name",uname);
              response.sendRedirect("/bbs/listarticle.jsp");  
           }
           if(isadmin==0&&isvalid==0)
           { 
            out.print("<font color='red'>"); 
            out.print("您注册后还未通过审核不能进入技术论坛管理系统");
            out.print("<br>经过5秒网页会自动转到登录页面");
            out.print("</font>");
            response.setHeader("Refresh","5;URL=login.html"); 
                 
           }
                  
         }
         else
         {
           out.print("<font color='red'>"); 
           out.print("用户名或密码错误");
           out.print("<br>经过5秒网页会自动转到登录页面");
           out.print("</font>");
           response.setHeader("Refresh","5;URL=login.html");
         
         }
                       
  
     
%>
</body>
</html>
异常：The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException: java.lang.Integer
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:460)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
root cause java.lang.ClassCastException: java.lang.Integer
org.apache.jsp.listarticle_jsp._jspService(listarticle_jsp.java:51)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.28 logs.小弟做毕业设计遇到这个问题，希望各位大侠帮我解决一下