How To Write Servlet Program For Login Page In Eclipse

How To Articles

In this article, I will guide you through the process of writing a servlet program for a login page in Eclipse. As a web developer, I have found servlets to be a powerful tool in creating dynamic web applications. They allow for server-side processing and interaction with the client’s request. So, if you’re ready, let’s dive into the world of servlet programming!

Setting up the Environment

Before we begin writing our servlet program, let’s make sure we have everything set up in Eclipse. First, ensure that you have the Java Development Kit (JDK) installed on your machine. You can download the latest version from the official Oracle website. Once you have installed the JDK, open Eclipse and create a new Dynamic Web Project.

After creating the project, you will see a directory structure in the project explorer. Right-click on the “src” folder, go to “New” and select “Servlet.” Fill in the necessary details like the servlet name and the package name. Click “Finish” to create the servlet file.

Writing the Servlet Program

Now that we have set up the environment, let’s start writing our servlet program. Open the servlet file you just created in Eclipse and override the `doGet()` and `doPost()` methods. These methods handle the HTTP GET and POST requests, respectively.


@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Your code for handling GET requests goes here
}

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Your code for handling POST requests goes here
}

Next, let’s focus on the login functionality. Inside the `doPost()` method, retrieve the username and password parameters from the request using the `getParameter()` method. You can validate the credentials against your database or any other authentication mechanism you prefer.


@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");

// Your authentication logic goes here
}

Creating the Login Page

Now that we have the servlet logic ready, let’s create a simple login page for our users. In the project explorer, right-click on the WebContent folder, go to “New” and select “HTML File.” Name the file “login.html” and click “Finish.” Open the file and add the necessary HTML code to create a form for the login page.





Login Page

Login






Ensure that the `action` attribute of the form points to the URL pattern of your servlet. In our case, it is “LoginServlet” as defined in the web.xml file.

Mapping the Servlet in web.xml

For our servlet to work, we need to map it in the web.xml file. In the project explorer, open the WebContent/WEB-INF folder and create a new XML file named “web.xml” if it doesn’t exist. Add the following code to the file:



MyServletApp


LoginServlet
com.example.LoginServlet


LoginServlet
/LoginServlet


Make sure to replace “com.example.LoginServlet” with the actual package and class name of your servlet. This configuration tells the server how to handle requests for the “/LoginServlet” URL pattern.

Running the Application

With everything in place, it’s time to run our application and see the login page in action. Right-click on your project in the project explorer, go to “Run As” and select “Run on Server.” Choose a server (e.g., Apache Tomcat) and click “Finish.”

You should see the login page in your web browser. Enter a username and password, and click the “Login” button. The form data will be sent to the servlet, and you can handle it as per your logic. You can then redirect the user to a different page based on the authentication result.

Conclusion

Writing a servlet program for a login page in Eclipse involves setting up the environment, writing the servlet code, creating the login page, and mapping the servlet in the web.xml file. While this tutorial provides a basic foundation, there are endless possibilities for enhancing the login functionality and building upon the servlet’s capabilities.

I hope this article has given you a good understanding of how to write a servlet program for a login page in Eclipse. Happy coding!