import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

@WebServlet("/DatabaseServlet")
public class DatabaseServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws IOException {
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;

        try {
            // 加载数据库驱动
            Class.forName("com.mysql.cj.jdbc.Driver");

            // 设置数据库连接信息
            String url = "jdbc:mysql://localhost:3306/your_database";
            String username = "your_username";
            String password = "your_password";

            // 创建数据库连接
            connection = DriverManager.getConnection(url, username, password);

            // 编写SQL查询语句
            String sql = "SELECT * FROM your_table";
            preparedStatement = connection.prepareStatement(sql);

            // 执行查询
            resultSet = preparedStatement.executeQuery();

            // 处理查询结果
            while (resultSet.next()) {
                // 获取数据并进行处理
                String columnName = resultSet.getString("column_name");
                // 具体操作...
            }

            // 其他数据库操作...

        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            // 关闭数据库资源
            try {
                if (resultSet != null) resultSet.close();
                if (preparedStatement != null) preparedStatement.close();
                if (connection != null) connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}