DECODE-IT

Complete Java Course

45-Day Python Course Roadmap: From Basics to Database Connectivity and Libraries

75 Day Study

Untitled page

Explore

Day 1: Introduction to Java

Day 15: JDBC - Database Connectivity

Java Database Connectivity (JDBC): A Comprehensive Guide

Introduction to JDBC

JDBC is a Java-based API that allows Java applications to interact with relational databases like MySQL, Oracle, PostgreSQL, and more. It provides a standard interface for connecting to databases, executing SQL queries, and handling query results.

Let's begin by importing the necessary Java packages for JDBC:

javaCopy code

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

Connecting to a Database

To connect to a database, you need to establish a connection using the Connection object. Here's how you can do it:

javaCopy code

public static Connection getConnection() throws SQLException {

String jdbcUrl = "jdbc:mysql://localhost:3306/mydatabase";

String username = "your_username";

String password = "your_password";

Connection connection = DriverManager.getConnection(jdbcUrl, username, password);

return connection;

}

Replace "jdbc:mysql://localhost:3306/mydatabase", "your_username", and "your_password" with your database URL, username, and password.

Executing SQL Queries

Once you have a connection, you can execute SQL queries. For instance, let's select all records from a table:

javaCopy code

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

public static void main(String[] args) {

try {

Connection connection = getConnection();

Statement statement = connection.createStatement();

String sql = "SELECT * FROM mytable";

ResultSet resultSet = statement.executeQuery(sql);

while (resultSet.next()) {

// Process each row of the result set here

}

connection.close();

} catch (SQLException e) {

e.printStackTrace();

}

Handling ResultSets

The ResultSet object contains the query result. You can iterate through it to retrieve data:

javaCopy code

while (resultSet.next()) {

int id = resultSet.getInt("id");

String name = resultSet.getString("name");

// Process data

}

Complete Login and Registration with database

package JavaCompleteCourse;

import javax.swing.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

public class day15 {

private static final String DB_URL = "jdbc:mysql://your_database_url:your_port/your_database_name";

private static final String DB_USER = "your_database_username";

private static final String DB_PASSWORD = "your_database_password";

private JFrame frame;

private JTextField usernameField;

private JPasswordField passwordField;

private JPanel loginPanel;

private JPanel welcomePanel;

public static void main(String[] args) {

SwingUtilities.invokeLater(() -> {

try {

new day15();

} catch (Exception e) {

e.printStackTrace();

}

});

}

public day15() {

frame = new JFrame("Login Example");

frame.setSize(400, 300);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setLayout(null);

loginPanel = createLoginPanel();

welcomePanel = createWelcomePanel();

frame.setContentPane(loginPanel);

frame.setVisible(true);

}

private JPanel createLoginPanel() {

JPanel panel = new JPanel();

panel.setLayout(null);

JLabel usernameLabel = new JLabel("Username:");

usernameLabel.setBounds(50, 50, 80, 25);

panel.add(usernameLabel);

JLabel passwordLabel = new JLabel("Password:");

passwordLabel.setBounds(50, 80, 80, 25);

panel.add(passwordLabel);

usernameField = new JTextField();

usernameField.setBounds(150, 50, 150, 25);

panel.add(usernameField);

passwordField = new JPasswordField();

passwordField.setBounds(150, 80, 150, 25);

panel.add(passwordField);

JButton loginButton = new JButton("Login");

loginButton.setBounds(50, 120, 100, 25);

panel.add(loginButton);

JButton registerButton = new JButton("Register");

registerButton.setBounds(200, 120, 100, 25);

panel.add(registerButton);

loginButton.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

String username = usernameField.getText();

char[] passwordChars = passwordField.getPassword();

String password = new String(passwordChars);

if (login(username, password)) {

frame.setContentPane(welcomePanel);

frame.revalidate();

} else {

JOptionPane.showMessageDialog(frame, "Invalid username or password.");

}

});

registerButton.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

String username = usernameField.getText();

char[] passwordChars = passwordField.getPassword();

String password = new String(passwordChars);

if (register(username, password)) {

JOptionPane.showMessageDialog(frame, "Registration successful!");

} else {

JOptionPane.showMessageDialog(frame, "Registration failed.");

}

});

return panel;

}

private JPanel createWelcomePanel() {

JPanel panel = new JPanel();

panel.setLayout(null);

JLabel welcomeLabel = new JLabel("Welcome!");

welcomeLabel.setBounds(150, 50, 100, 25);

panel.add(welcomeLabel);

JButton logoutButton = new JButton("Logout");

logoutButton.setBounds(150, 100, 100, 25);

panel.add(logoutButton);

logoutButton.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

frame.setContentPane(loginPanel);

frame.revalidate();

usernameField.setText("");

passwordField.setText("");

}

});

return panel;

}

private boolean login(String username, String password) {

try {

Connection connection = DriverManager.getConnection(DB_URL, DB_USER, DB_PASSWORD);

String query = "SELECT * FROM users WHERE username=? AND password=?";

PreparedStatement preparedStatement = connection.prepareStatement(query);

preparedStatement.setString(1, username);

preparedStatement.setString(2, password);

ResultSet resultSet = preparedStatement.executeQuery();

return resultSet.next();

} catch (Exception e) {

Want to print your doc?
This is not the way.

Try clicking the ⋯ next to your doc name or using a keyboard shortcut (

CtrlP

) instead.