Servlet - CRUD Operation with Example

CRUD stands for Create, Read, Update, and Delete, which are the basic operations used to manage data in a database. In this example, we will build a simple User Registration application using Servlet, MySQL, and JDBC to perform all CRUD operations.

• Used to manage user data such as adding, viewing, updating, and deleting records.
• Demonstrates how Servlet interacts with MySQL database using JDBC.
• Commonly used in real-world web applications for data management.

Prerequisites

• java 8 or + version
• MySQL(workbench) Database
• IDE(Intellij)
• Apache Tomcat (I used the Tomcat 9 version).

Steps to Impement Servlet - CRUD Operation

Step 1: Create Database (MySQL)

First, we create the database and table in MySQL and appuserdb is the database user table stores user detailsi and id is auto-incremented.

Step 2: Create Project (IntelliJ + Tomcat)

After that we set up our project, for this example am using Intellij IDE, 

• Create a new project by selecting File( it will show you various options)
• Select New, then project
• Click on Java Enterprise and choose web application as your project Template

Setting Up Application server

• Select the application and choose new
• Select Tomcat base directory(The one saved in your working directory)

This is what the project structure will look like:

Step 3: Create Model Class (User.java)

Represents database table structure it is Used to transfer user data between layers

Step 4: Create Database Connection (UserDaoHandler.java)

Then we create a class that helps to perform CRUD operations on our database,

Step 5: Create servlet class (AddUser)

AddUser.java for adding users to the database.

Step 6: Create servlet class (UpdateUser)

This method gets the user id and matches it to the one in the database, then does an update on it.

Step 7: Create servlet class (PatchUser)

This method simply exchanges information on the database to the input parameters gotten from the web page and saves it into the database.

Step 8: Create servlet class (ViewUser)

This method gets all users from the database and displays it in a simple table format.

Step 9: Create servlet class (Delete)

The method below deletes the user from the database and sends the user view response, displaying the current users in the database.

Step 10: Run Your application

• Start the Apache Tomcat server from IntelliJ IDEA.
• Right-click the project and select Run to deploy the application on the server.
• Open the browser and access the application using the Tomcat URL:

http://localhost:8080/appuser_war_exploded/

Output:

The Java servlet renders the Java server page anytime a user calls.

when user succesfully inserted the data and Record saved succesfully message shown on the browser screen.

When we want to add a user The browser show the page

Explanation: The application uses Servlets to handle user requests and JDBC to interact with the MySQL database. Each servlet performs a specific CRUD operation such as adding, viewing, updating, or deleting users. The DAO class manages all database queries, while the User model stores user data throughout the application flow.