How does Java interact with databases?

Java is able to interact with databases through the JDBC (Java Database Connectivity) API. Here are some basic steps: 1. Import the JDBC package: To use JDBC in a Java project, you need to import the JDBC package, which can be done by adding dependencies through build tools like Maven or Gradle, or manually downloading and importing the JAR file. 2. Load the database driver: Use the Class.forName() method in your code to load the database driver. Different databases have different driver classes, for example, the driver class for MySQL is com.mysql.jdbc.Driver. 3. Establish a database connection: Use the DriverManager.getConnection() method to establish a connection with the database. You will need to provide connection parameters such as the database URL, username, and password. 4. Create a Statement or PreparedStatement object: Use the createStatement() or prepareStatement() method of the connection object to create a Statement or PreparedStatement object for executing SQL queries. 5. Execute SQL queries: Use the executeQuery() method of the Statement or PreparedStatement object to execute select queries and use the executeUpdate() method to execute insert, update, or delete queries. 6. Handle query results: For select queries, you can use the ResultSet object’s next() and getXXX() methods to iterate over and retrieve data from the result set. 7. Close the connection: Use the close() method of the connection object to close the connection to the database and release resources. Below is a simple example code that demonstrates how to connect to a MySQL database and execute a query.

import java.sql.*;
public class JDBCTest {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            // 加载数据库驱动
            Class.forName("com.mysql.jdbc.Driver");
            // 建立数据库连接
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", 
            "password");
            // 创建Statement对象
            stmt = conn.createStatement();
            // 执行查询语句
            rs = stmt.executeQuery("SELECT * FROM users");
            // 处理查询结果
            while (rs.next()) {
                String username = rs.getString("username");
                String password = rs.getString("password");
                System.out.println("Username: " + username + ", Password: " + password);
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            // 关闭连接和释放资源
            try {
                if (rs != null) rs.close();
                if (stmt != null) stmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

The above code demonstrates basic database connection and query operations. In practical applications, PreparedStatement can be used to execute parameterized SQL statements to enhance security and performance. Additionally, JDBC’s transaction management feature can be utilized to ensure consistency in multiple database operations.