Java Servlets: HTML Forms and MySQL DB

• Extends knowledge of Java Servlets for handling user input through HTML forms and database interaction.
• Covers handling POST requests, connecting to MySQL with JDBC, and performing basic CRUD operations.

Prerequisites

• Completion of Java Servlets Tutorial Part 1 for basic servlet setup in NetBeans with GlassFish
• Installed MySQL Database
• JDBC Driver for MySQL, such as mysql-connector-java

Setting Up a Database

• Install and configure MySQL.
• Create a database for the tutorial via MySQL Workbench or the Command Line:

  CREATE DATABASE userdb;
  USE userdb;
  

• Create table to store user data:

  CREATE TABLE users (
  id INT AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(50) NOT NULL,
  email VARCHAR(50) NOT NULL UNIQUE
  );
  

Handling Forms in Servlets

• Build a simple form for users to enter their names and email addresses, processed and stored by the servlet.
• The form submits data to the /register URL using the POST method.

Connecting to a Database Using JDBC

• Download the MySQL Connector/J
• In NetBeans, right-click on the Libraries node in your project.
• Select Add Library > Add JAR/Folder, and add the mysql-connector-java-X.X.X-bin.jar file.
• Create a servlet named RegisterServlet to handle the form submission.
• JDBC URL, username, and password provide connection details for the MySQL server.
• DriverManager establishes a connection with the database
• PreparedStatement is used to insert form data into the users table
• doPost() handles the form submission (POST request) and inserts the data into the database
• Map RegisterServlet to the /register URL in web.xml.

Running the Application

• Run the project in NetBeans
• Navigate to http://localhost:8080/MyFirstServletApp/register.html.
• Fill in and submit the form.
• Success message indicates data insertion into the MySQL database.

Displaying Data from the Database

• Create a servlet to display registered users (UserListServlet).
• JDBC URL is jdbc:mysql://localhost:3306/userdb.
• JDBC_USER is "root".
• JDBC_PASSWORD is "password".
• doGet() handles the HTTP GET request
• ResultSet rs = stmt.executeQuery("SELECT * FROM users") executes the query to retrieve all users
• Map the servlet in web.xml:

  <servlet>
  		<servlet-name>UserListServlet</servlet-name>
  		<servlet-class>com.example.servlet.UserListServlet</servlet-class>
  </servlet>
  <servlet-mapping>
  		<servlet-name>UserListServlet</servlet-name>
  		<url-pattern>/users</url-pattern>
  </servlet-mapping>
  

Running the Application

• Restart the GlassFish server.
• Access http://localhost:8080/MyFirstServletApp/users.
• Displays a list of users registered via the form.