Example Of Login Form In Servlet Tutorial

A Simple example of creating the login form using Servlet is going to be made in this example. By making use of oracle10g as the database. Five files are required for this example.

• index.html
• FirstServlet.java
• LoginDao.java
• SecondServlet.java
• web.xml

We need to make a table userreg with names and pass fields. Also, it must contain some amount of data. The table must be as:

create table userreg(name varchar2(40),pass varchar2(40));  

Index.html

<form action="servlet1" method="post">  
Name:<input type="text" name="username"/><br/><br/>  
Password:<input type="password" name="userpass"/><br/><br/>  
<input type="submit" value="login"/>  
</form>  

FirstServlet.java

import java.io.IOException;  
import java.io.PrintWriter;  
  
import javax.servlet.RequestDispatcher;  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
  
  
public class FirstServlet extends HttpServlet {  
public void doPost(HttpServletRequest request, HttpServletResponse response)  
        throws ServletException, IOException {  
  
    response.setContentType("text/html");  
    PrintWriter out = response.getWriter();  
          
    String n=request.getParameter("username");  
    String p=request.getParameter("userpass");  
          
    if(LoginDao.validate(n, p)){  
        RequestDispatcher rd=request.getRequestDispatcher("servlet2");  
        rd.forward(request,response);  
    }  
    else{  
        out.print("Sorry username or password error");  
        RequestDispatcher rd=request.getRequestDispatcher("index.html");  
        rd.include(request,response);  
    }  
          
    out.close();  
    }  
}  

LoginDao.java

import java.sql.*;  
  
public class LoginDao {  
public static boolean validate(String name,String pass){  
boolean status=false;  
try{  
Class.forName("oracle.jdbc.driver.OracleDriver");  
Connection con=DriverManager.getConnection(  
"jdbc:oracle:thin:@localhost:1521:xe","system","oracle");  
      
PreparedStatement ps=con.prepareStatement(  
"select * from userreg where name=? and pass=?");  
ps.setString(1,name);  
ps.setString(2,pass);  
      
ResultSet rs=ps.executeQuery();  
status=rs.next();  
          
}catch(Exception e){System.out.println(e);}  
return status;  
}  
}  

WelcomeServlet.java

import java.io.IOException;  
import java.io.PrintWriter;  
  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
  
public class WelcomeServlet extends HttpServlet {  
public void doPost(HttpServletRequest request, HttpServletResponse response)  
    throws ServletException, IOException {  
  
    response.setContentType("text/html");  
    PrintWriter out = response.getWriter();  
          
    String n=request.getParameter("username");  
    out.print("Welcome "+n);  
          
    out.close();  
    }  
  
}  

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