Java Database Connectivity (JDBC)

Java Database Connectivity (JDBC) is a vital API that facilitates seamless communication between Java applications and databases. It enables developers to establish connections, execute SQL queries, and retrieve data from databases.

Example of Connecting to a Database:

import java.sql.*;

public class JdbcExample {
public static void main(String[] args) {
String url = “jdbc:mysql://localhost:3306/mydatabase”;
String username = “username”;
String password = “password”;

try (Connection connection = DriverManager.getConnection(url, username, password)) {
System.out.println(“Connected to the database!”);
} catch (SQLException e) {
e.printStackTrace();
}
}
}

JDBC empowers developers to execute SQL queries and interact with the database effectively. You can perform operations like INSERT, SELECT, UPDATE, and DELETE to manage data.

Example of Executing SQL Query:

try (Statement statement = connection.createStatement()) {
String sql = “SELECT * FROM employees”;
ResultSet resultSet = statement.executeQuery(sql);

while (resultSet.next()) {
int id = resultSet.getInt(“id”);
String name = resultSet.getString(“name”);
double salary = resultSet.getDouble(“salary”);
System.out.println(“Employee ID: ” + id + “, Name: ” + name + “, Salary: ” + salary);
}
} catch (SQLException e) {
e.printStackTrace();
}

To prevent SQL injection attacks, JDBC provides PreparedStatement, which allows parameterized queries and automatically escapes user input.

Example of PreparedStatement:

String name = “John”;
int age = 25;

String sql = “SELECT * FROM employees WHERE name = ? AND age = ?”;
try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
preparedStatement.setString(1, name);
preparedStatement.setInt(2, age);

ResultSet resultSet = preparedStatement.executeQuery();

while (resultSet.next()) {
// process the result set
}
} catch (SQLException e) {
e.printStackTrace();
}