Login Code Error

Pranit Sonawane

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Posts: 172

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posted 5 years ago

This is my Login Code

Web Page Login.jsp

loginbean.jsp to set the parameter of the login.

LoginBean.java to mapping the parameter of loginbean.jsp

login.java to validate the user login

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.sql.*;
import java.sql.*;
public class login extends HttpServlet{ 
 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException,IOException{
  response.setContentType("text/html");
  PrintWriter out = response.getWriter();
  System.out.println("MySQL Connect Example.");
  Connection conn = null;
  String url = "jdbc:mysql://localhost:3306/";
  String dbName = "user_register";
  String driver = "com.mysql.jdbc.Driver";
  String userName = "root"; 
  String password = "root";
 String username="";
 String userpass="";
 String strQuery= ""; 
  Statement st=null;
  ResultSet rs=null;
  HttpSession session = request.getSession(true);
  try {
  Class.forName(driver).newInstance();
  conn = DriverManager.getConnection(url+dbName,userName,password);
  if(request.getParameter("username")!=null &&
     request.getParameter("username")!="" && request.getParameter("password")!=null &&
     request.getParameter("password")!="")
  {
  username = request.getParameter("username").toString();
  userpass = request.getParameter("password").toString();
  strQuery="select * from userregister where 
    username='"+username+"' and  password='"+userpass+"'";
 System.out.println(strQuery);
  st = conn.createStatement();
  rs = st.executeQuery(strQuery);
  int count=0;
  while(rs.next())
  {
  session.setAttribute("username",rs.getString(2));
  count++;
  }
  if(count>0)
  {
  response.sendRedirect("welcome.jsp");
  }
  else
  {
 response.sendRedirect("login.jsp");
  }
  }
  else
  {
 response.sendRedirect("login.jsp");
  }
  System.out.println("Connected to the database"); 
  conn.close();
  System.out.println("Disconnected from database");
  } catch (Exception e) {
  e.printStackTrace();
  }
  }
}

welcome.jsp

it gives me error saying Jasper Exception cannot retrieve details from 'username' field.

please Help
Many Thanks
Pranit

Palak Mathur

Ranch Hand

Posts: 343

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posted 5 years ago

Pranit Sonawane wrote:This is my Login Code

Web Page Login.jsp

<html> <head> </head> <body> <form name="loginform" method="post" action="loginbean.jsp"> <br><br> <table align="center"><tr><td><h2>Login Authentication</h2></td></tr></table> <table width="300px" align="center" style="border:1px solid #000000;background-color:#efefef;"> <tr><td colspan=2></td></tr> <tr><td colspan=2> </td></tr> <tr> <td><b>Login Name</b></td> <td><input type="text" name="userName" value=""></td> </tr> <tr> <td><b>Password</b></td> <td><input type="password" name="password" value=""></td> </tr> <tr> <td></td> <td><input type="submit" name="Submit" value="Submit"></td> </tr> <tr><td colspan=2> </td></tr> </table> </form> </body> </html>

loginbean.jsp to set the parameter of the login.

<%@ page language="Java" import="java.sql.*" %> <HTML> <HEAD><TITLE>DataBase Search</TITLE></HEAD> <BODY> <jsp:useBean id="db" scope="request" class="logbean.LoginBean" > <jsp:setProperty name="db" property="userName" value="<%=request.getParameter("userName")%>"/> <jsp:setProperty name="db" property="password" value="<%=request.getParameter("password")%>"/> </jsp:useBean> <jsp:forward page="hello"> <jsp:param name="username" value="<%=db.getUserName()%>" /> <jsp:param name="password" value="<%=db.getPassword()%>" /> </jsp:forward> </body> </html>

LoginBean.java to mapping the parameter of loginbean.jsp

package logbean; public class LoginBean { String userName=""; String password=""; public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }

login.java to validate the user login
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import javax.sql.*; import java.sql.*; public class login extends HttpServlet{ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException{ response.setContentType("text/html"); PrintWriter out = response.getWriter(); System.out.println("MySQL Connect Example."); Connection conn = null; String url = "jdbc:mysql://localhost:3306/"; String dbName = "user_register"; String driver = "com.mysql.jdbc.Driver"; String userName = "root"; String password = "root"; String username=""; String userpass=""; String strQuery= ""; Statement st=null; ResultSet rs=null; HttpSession session = request.getSession(true); try { Class.forName(driver).newInstance(); conn = DriverManager.getConnection(url+dbName,userName,password); if(request.getParameter("username")!=null && request.getParameter("username")!="" && request.getParameter("password")!=null && request.getParameter("password")!="") { username = request.getParameter("username").toString(); userpass = request.getParameter("password").toString(); strQuery="select * from userregister where username='"+username+"' and password='"+userpass+"'"; System.out.println(strQuery); st = conn.createStatement(); rs = st.executeQuery(strQuery); int count=0; while(rs.next()) { session.setAttribute("username",rs.getString(2)); count++; } if(count>0) { response.sendRedirect("welcome.jsp"); } else { response.sendRedirect("login.jsp"); } } else { response.sendRedirect("login.jsp"); } System.out.println("Connected to the database"); conn.close(); System.out.println("Disconnected from database"); } catch (Exception e) { e.printStackTrace(); } } }

welcome.jsp

<HTML> <HEAD><TITLE>Welcome</TITLE></HEAD> <BODY> <br><br><br><br> <table align="center" style="border:1px solid #000000;"> <% if(session.getAttribute("username")!=null && session.getAttribute("username")!="") { String user = session.getAttribute("username").toString(); %> <tr><td align="center"><h1>Welcome <b><%= user%></b></h1></td></tr> <% } %> </table> </body> <html>

it gives me error saying Jasper Exception cannot retrieve details from 'username' field.

please Help
Many Thanks
Pranit

Where and when are you getting error? You have pasted your entire code. Paste the stacktrace also.

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Pranit Sonawane

Ranch Hand

Posts: 172

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posted 5 years ago

Palak Mathur wrote:

Pranit Sonawane wrote:This is my Login Code

Web Page Login.jsp

<html> <head> </head> <body> <form name="loginform" method="post" action="loginbean.jsp"> <br><br> <table align="center"><tr><td><h2>Login Authentication</h2></td></tr></table> <table width="300px" align="center" style="border:1px solid #000000;background-color:#efefef;"> <tr><td colspan=2></td></tr> <tr><td colspan=2> </td></tr> <tr> <td><b>Login Name</b></td> <td><input type="text" name="userName" value=""></td> </tr> <tr> <td><b>Password</b></td> <td><input type="password" name="password" value=""></td> </tr> <tr> <td></td> <td><input type="submit" name="Submit" value="Submit"></td> </tr> <tr><td colspan=2> </td></tr> </table> </form> </body> </html>

loginbean.jsp to set the parameter of the login.

<%@ page language="Java" import="java.sql.*" %> <HTML> <HEAD><TITLE>DataBase Search</TITLE></HEAD> <BODY> <jsp:useBean id="db" scope="request" class="logbean.LoginBean" > <jsp:setProperty name="db" property="userName" value="<%=request.getParameter("userName")%>"/> <jsp:setProperty name="db" property="password" value="<%=request.getParameter("password")%>"/> </jsp:useBean> <jsp:forward page="hello"> <jsp:param name="username" value="<%=db.getUserName()%>" /> <jsp:param name="password" value="<%=db.getPassword()%>" /> </jsp:forward> </body> </html>

LoginBean.java to mapping the parameter of loginbean.jsp

package logbean; public class LoginBean { String userName=""; String password=""; public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }

login.java to validate the user login
import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import javax.sql.*; import java.sql.*; public class login extends HttpServlet{ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException{ response.setContentType("text/html"); PrintWriter out = response.getWriter(); System.out.println("MySQL Connect Example."); Connection conn = null; String url = "jdbc:mysql://localhost:3306/"; String dbName = "user_register"; String driver = "com.mysql.jdbc.Driver"; String userName = "root"; String password = "root"; String username=""; String userpass=""; String strQuery= ""; Statement st=null; ResultSet rs=null; HttpSession session = request.getSession(true); try { Class.forName(driver).newInstance(); conn = DriverManager.getConnection(url+dbName,userName,password); if(request.getParameter("username")!=null && request.getParameter("username")!="" && request.getParameter("password")!=null && request.getParameter("password")!="") { username = request.getParameter("username").toString(); userpass = request.getParameter("password").toString(); strQuery="select * from userregister where username='"+username+"' and password='"+userpass+"'"; System.out.println(strQuery); st = conn.createStatement(); rs = st.executeQuery(strQuery); int count=0; while(rs.next()) { session.setAttribute("username",rs.getString(2)); count++; } if(count>0) { response.sendRedirect("welcome.jsp"); } else { response.sendRedirect("login.jsp"); } } else { response.sendRedirect("login.jsp"); } System.out.println("Connected to the database"); conn.close(); System.out.println("Disconnected from database"); } catch (Exception e) { e.printStackTrace(); } } }

welcome.jsp

<HTML> <HEAD><TITLE>Welcome</TITLE></HEAD> <BODY> <br><br><br><br> <table align="center" style="border:1px solid #000000;"> <% if(session.getAttribute("username")!=null && session.getAttribute("username")!="") { String user = session.getAttribute("username").toString(); %> <tr><td align="center"><h1>Welcome <b><%= user%></b></h1></td></tr> <% } %> </table> </body> <html>

it gives me error saying Jasper Exception cannot retrieve details from 'username' field.

please Help
Many Thanks
Pranit

Where and when are you getting error? You have pasted your entire code. Paste the stacktrace also.

Jasper Exception cannot retrieve details from 'username' field.

This is my error i have mentioned it already

Punit Jain

Ranch Hand

Posts: 1085

posted 5 years ago

Pranit, palak means posting only exception like this

not helps, post your full stack trace, not only single line.
means output of this:

Rob Spoor

Sheriff

Posts: 21095

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posted 5 years ago

Punit is right. I've now seen that piece of code three times (twice in quotes) and I still have no idea where the error comes from.

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