Login Form Servlet + JDBC + MySQL Example

This article is a series of Servlet tutorials. In this article, we will build a simple Employee login module using Servlet, JDBC, and the MySQL database.

Learn complete Servlet at https://www.javaguides.net/p/servlet-tutorial.html

Notice that in this article, we are not using JSP to develop a web application. If you want to use JSP and servlet together then check out the below tutorials:

• JSP Servlet JDBC MySQL CRUD Example Tutorial

• Servlet + JSP + JDBC + MySQL Example

• Registration Form using JSP + Servlet + JDBC + Mysql Example

• Login Form using JSP + Servlet + JDBC + MySQL Example

In this example, we will write the JDBC code separate from the Servlet. Servlet file we will be used only for handling HTTP requests and business logic. We use the JDBC API to connect to the MySQL database.

You can download the source code of this article from my GitHub repository. The link has given at end of this article.

What we will build?

We will build a simple Employee login module using Servlet, JDBC, and the MySQL database. Here is the login form:

Tools and technologies used

• IDE - STS/Eclipse Neon.3
• JDK - 1.8 or later
• Apache Tomcat - 8.5
• Servlet - 2.5+
• MySQL - mysql-connector-java-8.0.13.jar

Development Steps

1. Create Eclipse Dynamic web project
2. Add Dependencies
3. Project Structure
4. MySQL Database Setup
5. Create a JavaBean - Login.java
6. Create a LoginDao.java
7. Create LoginServlet.java
8. Create a login.html
9. Create a loginsuccess.html
10. Demo

1. Create an Eclipse Dynamic Web Project

To create a new dynamic Web project in Eclipse:

1. On the main menu select File > New > Project....

2. In the upcoming wizard choose Web > Dynamic Web Project.

3. Click Next.

4. Enter project name as "login-servlet-jdbc-example";
5. Make sure that the target runtime is set to Apache Tomcat with the currently supported version. 

2. Add Dependencies

Add the latest release of the below jar files to the lib folder.

- servlet-api.2.3.jar
- mysql-connector-java-8.0.13.jar

In Eclipse, paste these JAR files to your project directory: WebContent/WEB-INF/lib

3. Project Structure

Standard project structure for your reference - 

4. MySQL Database Setup

Let's create a database named "demo" in MySQL. Now, create a login table using the below DDL script:

CREATE TABLE `login` (
  `username` varchar(45) NOT NULL,
  `password` varchar(45) DEFAULT NULL,
  PRIMARY KEY (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

Here is an Insert SQL statement:

INSERT INTO `demo`.`login` (`username`, `password`) VALUES ("Ramesh", "Ramesh");

5. Create a JavaBean - LoginBean.java

Let's create an Employee JavaBean class which we will use to create an object and populate registration data in Servlet:

import java.io.Serializable;

public class LoginBean implements Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = 1 L;
    private String username;
    private 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;
    }
}

6. Create a LoginDao.java

We will separate JDBC accessing code separate from Servlet. 

So let's create a LoginDao.java class and add the following code to it:

package net.javaguides.login.database;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import net.javaguides.login.bean.LoginBean;

public class LoginDao {

    public boolean validate(LoginBean loginBean) throws ClassNotFoundException {
        boolean status = false;

        Class.forName("com.mysql.jdbc.Driver");

        try (Connection connection = DriverManager
            .getConnection("jdbc:mysql://localhost:3306/demo?useSSL=false", "root", "root");

            // Step 2:Create a statement using connection object
            PreparedStatement preparedStatement = connection
            .prepareStatement("select * from login where username = ? and password = ? ")) {
            preparedStatement.setString(1, loginBean.getUsername());
            preparedStatement.setString(2, loginBean.getPassword());

            System.out.println(preparedStatement);
            ResultSet rs = preparedStatement.executeQuery();
            status = rs.next();

        } catch (SQLException e) {
            // process sql exception
            printSQLException(e);
        }
        return status;
    }

    private void printSQLException(SQLException ex) {
        for (Throwable e: ex) {
            if (e instanceof SQLException) {
                e.printStackTrace(System.err);
                System.err.println("SQLState: " + ((SQLException) e).getSQLState());
                System.err.println("Error Code: " + ((SQLException) e).getErrorCode());
                System.err.println("Message: " + e.getMessage());
                Throwable t = ex.getCause();
                while (t != null) {
                    System.out.println("Cause: " + t);
                    t = t.getCause();
                }
            }
        }
    }
}

7. Create a LoginServlet.java

Let's create LoginServlet to process HTTP request parameters and redirect to the appropriate HTML page based on the employee login status.

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import net.javaguides.login.bean.LoginBean;
import net.javaguides.login.database.LoginDao;

/**
 * @email Ramesh Fadatare
 */

@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1 L;
    private LoginDao loginDao;

    public void init() {
        loginDao = new LoginDao();
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {

        String username = request.getParameter("username");
        String password = request.getParameter("password");
        LoginBean loginBean = new LoginBean();
        loginBean.setUsername(username);
        loginBean.setPassword(password);

        try {
            if (loginDao.validate(loginBean)) {
                response.sendRedirect("loginsuccess.html");
            } else {
                HttpSession session = request.getSession();
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

8. Create a login.html

Let's design a login HTML form with the following fields:

• username
• password

<!DOCTYPE html>
<html>

<head>
    <meta charset="ISO-8859-1">
    <title>Insert title here</title>
</head>

<body>
    <div align="center">
        <h1>Employee Login Form</h1>
        <form action="login" method="post">
            <table style="with: 100%">
                <tr>
                    <td>UserName</td>
                    <td><input type="text" name="username" /></td>
                </tr>
                <tr>
                    <td>Password</td>
                    <td><input type="password" name="password" /></td>
                </tr>
            </table>
            <input type="submit" value="Submit" />
        </form>
    </div>
</body>
</html>

9. Create a loginsuccess.html

After an employee successfully login then this page shows a successful message on the screen:

<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
 <div align="center">
  <h1>You have logined successfully</h1>
 </div>
</body>
</html>

10. Demo

It's time to see a demo of the above development. Deploy this web application to the tomcat server.

Employee Login Form

Once you deploy this application successfully then hit this link into a browser - http://localhost:8080/login-servlet-jdbc-mysql-example/login.html

Employee Login Success Page

Related Servlet Articles

• Servlet Life Cycle

• Servlet Interface Example

• GenericServlet Class Example

• HttpServlet Class Example Tutorial

• HttpServlet doGet() Method Example

• HttpServlet doPost() Method Example

• ServletConfig Interface Example

• @WebServlet Annotation Example

• @WebInitParam Annotation Example

• @WebListener Annotation Example

• @WebFilter Annotation Example

• @MultipartConfig Annotation Example

• How to Return a JSON Response from a Java Servlet

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