Servlet :
package com.arham.servlet;
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;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.SQLException;
public class logincheck extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter(“username”).toString();
String password = request.getParameter(“password”).toString();
Connection connection = null;
try {
String driverName = “org.gjt.mm.mysql.Driver”; // MySQL MM JDBC driver
Class.forName(driverName);
String serverName = “localhost”;
String mydatabase = “arhamjava”;
String url = “jdbc:mysql://” + serverName + “/” + mydatabase; // a JDBC url
String sqlusername = “root”;
String sqlpassword = “MyP@SsW0rD”;
connection = DriverManager.getConnection(url, sqlusername, sqlpassword);
}
catch (ClassNotFoundException e) {
// Could not find the database driver
}
catch (SQLException e) {
// Could not connect to the database
}
Statement stmt = null;
ResultSet rs = null;
String checkUsername = null;
String checkPassword = null;
int checkAccessPower = 0;
try
{
stmt = connection.createStatement();
rs = stmt.executeQuery(“SELECT username, password, accesspower FROM account WHERE username = ‘” + username + “‘ AND id > 0”);
PrintWriter out2 = response.getWriter();
while(rs.next())
{
checkUsername = rs.getString(“username”);
checkPassword = rs.getString(“password”);
checkAccessPower = rs.getInt(“accesspower”);
}
if(checkUsername != null)
{
if(checkPassword.equals(password))
{
out2.println(“Welcome ” + username + “<br/> <h2>Login Success</h2>”);
if(checkAccessPower > 150)
out2.println(“Status : ADMIN”);
else if (checkAccessPower > 50)
out2.println(“Status : Normal User”);
else if (checkAccessPower < 9)
out2.println(“You have been banned by admin. Contact your administrator for clarification”);
}
else
out2.println(“<h1>Login Fail</h1> <br/> Click back to relogin!”);
}
else
out2.println(“<h2>Login Fail</h2> <br/> Reason : Your username not exist in our database.”);
}
catch (SQLException ex)
{
// handle any errors
System.out.println(“SQLException: ” + ex.getMessage());
System.out.println(“SQLState: ” + ex.getSQLState());
System.out.println(“VendorError: ” + ex.getErrorCode());
}
response.setContentType(“text/html;charset=UTF-8”);
PrintWriter out = response.getWriter();
try {
out.println(“<html>”);
out.println(“<head>”);
out.println(“<title>Servlet Login Check </title>”);
out.println(“</head>”);
out.println(“<body>”);
out.println(“</body>”);
out.println(“</html>”);
} finally
{
out.close();
}
}
// <editor-fold defaultstate=”collapsed” desc=”HttpServlet methods. Click on the + sign on the left to edit the code.”>
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
@Override
public String getServletInfo() {
return “Short description”;
}// </editor-fold>
}
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