如何更新Java Servlet代码

// 导入相关的类库
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Doupdateservlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        // 获取表单提交的数据
        String name = request.getParameter("name");
        String age = request.getParameter("age");
        String email = request.getParameter("email");
        String id = request.getParameter("id");

        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            // 加载数据库驱动
            Class.forName("com.mysql.jdbc.Driver");
            // 连接数据库
            String url = "jdbc:mysql://localhost:3306/mydb";
            String user = "root";
            String password = "password";
            conn = DriverManager.getConnection(url, user, password);
            // 定义SQL语句
            String sql = "UPDATE user SET name = ?, age = ?, email = ? WHERE id = ?";
            stmt = conn.prepareStatement(sql);
            // 绑定参数
            stmt.setString(1, name);
            stmt.setInt(2, Integer.parseInt(age));
            stmt.setString(3, email);
            stmt.setInt(4, Integer.parseInt(id));
            // 执行更新操作
            int rows = stmt.executeUpdate();
            if (rows > 0) {
                response.sendRedirect("list.jsp");
            } else {
                response.sendRedirect("error.jsp");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}