웹에서 입력받은 값을 엔터값 입력시 자동으로 mysql에 있는 데이터랑 비교해서

같을경우 출력이나 alert를 주려고 하는데... 에러가 나네요 ㅠㅠ

어떤식으로 해야되는지좀 알려주세요..

db_code.equlas(id)이부분에 널값이 들어가는거같은데;;;; 

어떻게해야될까요;

 

<%@ page language="java" contentType="text/html; charset=EUC-KR"
 import="java.sql.*" pageEncoding="EUC-KR"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=EUC-KR">
<title>Insert title here</title>
</head>
<body>
 <input type=text id=loginId value="" onkeyup=onKeyupPasswd(event)>
</body>
</html>
<script type="text/javascript">
function onKeyupPasswd(ev){
 var objLoginInfo = document.getElementById("loginId");
            var evKeyup = null;
            if(ev)                                            // firefox
                evKeyup = ev;   
            else                                            // explorer
                evKeyup = window.event;
               
            if(evKeyup.keyCode == 13){                        // enter key code:13
               // document.getElementById("passwd").blur();
                //fnLogin();
                <%
                String id = request.getParameter("objLoginInfo");
          

          Connection conn = null;
          Statement stmt = null;
          ResultSet rs = null;
          String db_code=null;
          //Boolean isLogin = false;

          try {
           Class.forName("com.mysql.jdbc.Driver");
           conn = DriverManager.getConnection(
             "jdbc:mysql://localhost:3306/mobileskhu?"
               + "characterEncoding=utf-8", "root_user",
             "tkdcjs2");

           stmt = (Statement) conn.createStatement();
           // 현재 페이지의 글 가져오기
           rs = stmt.executeQuery("select * from student where code='"
             + id + "'");
           while (rs.next()) {
            db_code = rs.getString("code");
           }
           if (db_code.equals(id)) {
            out.print("성공");
            }
/*
            if (!isLogin) {
             out.print("회원정보가 없습니다. ");
          
            } */
          }

          catch (ClassNotFoundException cnfe) {
           out.println("해당 클래스를 찾을 수 없습니다." + cnfe.getMessage());
          }

          catch (SQLException se) {
           out.println(se.getMessage());
          }

          try {
           conn.close();
          } catch (SQLException e) {
           out.println(e.getMessage());
          }
         %>
               
              

            }    // end if
       
        }    // end function onKeyupPasswd()
        </script>

 

에러 메시지는 이거에요 ㅠ

type Exception report

message An exception occurred processing JSP page /code.jsp at line 49

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /code.jsp at line 49

46:         			while (rs.next()) { 
47:         				db_code = rs.getString("code");
48:         			}
49:         			if (db_code.equals(id)) {
50:         				out.print("성공");
51:         				}
52: /* 


Stacktrace:
	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

root cause

java.lang.NullPointerException
	org.apache.jsp.code_jsp._jspService(code_jsp.java:111)
	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:728)