java 根据前端返回的字段名进行查询数据

import java.sql.*;

public class Main {
    public static void main(String[] args) {
        try {
            // 建立数据库连接
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");

            // 创建查询语句
            String fieldName = "name"; // 假设前端返回的字段名为"name"
            String query = "SELECT * FROM mytable WHERE " + fieldName + " = ?";

            // 创建PreparedStatement对象，并设置参数
            PreparedStatement stmt = conn.prepareStatement(query);
            stmt.setString(1, "John"); // 假设要查询的值为"John"

            // 执行查询
            ResultSet rs = stmt.executeQuery();

            // 处理查询结果
            while (rs.next()) {
                // 获取查询结果的字段值
                String name = rs.getString("name");
                int age = rs.getInt("age");
                // 其他字段类似

                // 处理查询结果，例如打印或返回给前端
                System.out.println("Name: " + name + ", Age: " + age);
            }

            // 关闭资源
            rs.close();
            stmt.close();
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}