Java JDBC Tutorial: Connecting to Databases with Java

JDBC (Java Database Connectivity) is a Java API that enables Java applications to interact with relational databases. It provides a standard way to execute SQL statements and retrieve data.

Key Components of JDBC

JDBC relies on several core classes and interfaces:

• Driver: Manages the connection to the database (e.g., MySQL, PostgreSQL).
• Connection: Represents a connection to a specific database.
• Statement: Executes SQL queries and updates.
• ResultSet: Stores the data returned from a database query.
• PreparedStatement: Used for precompiled SQL statements to prevent SQL injection.

Steps to Use JDBC

1. Add JDBC Driver
   Include the appropriate JDBC driver JAR (e.g., mysql-connector-java) in your project.
   💡 Example: For MySQL, use com.mysql.cj.jdbc.Driver.

2. Load the Driver
   Register the driver with the DriverManager class.

   Class.forName("com.mysql.cj.jdbc.Driver");
   

3. Establish a Connection
   Use DriverManager.getConnection() to connect to the database.
   🔗 Example:

   Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "user", "password");
   

4. Execute SQL Queries
   Create a Statement or PreparedStatement to run SQL commands.
   📜 Example:

   Statement stmt = conn.createStatement();
   ResultSet rs = stmt.executeQuery("SELECT * FROM users");
   

5. Process Results
   Iterate through ResultSet to extract data.
   📌 Example:

   while (rs.next()) {
       int id = rs.getInt("id");
       String name = rs.getString("name");
   }
   

6. Close Resources
   Always close ResultSet, Statement, and Connection to avoid leaks.
   🧹 Use try-with-resources for automatic cleanup:

   try (Connection conn = ...) {
       // Code here
   }
   

Best Practices

✅ Use PreparedStatement for dynamic queries.
✅ Implement connection pooling for performance.
✅ Handle exceptions properly and close resources in finally blocks.
✅ Avoid hardcoding database credentials in production code.

Expand Your Knowledge

For a deeper dive into database connections in Java, check out our Java Database Connections Guide.