将3个不同的值从数据库放入Hashmap

import java.sql.*;
import java.util.HashMap;

public class DatabaseToHashMap {
    public static void main(String[] args) {
        // 数据库连接信息
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String username = "root";
        String password = "password";

        // 创建HashMap对象
        HashMap<String, String> hashMap = new HashMap<>();

        // 连接数据库并查询数据
        try (Connection connection = DriverManager.getConnection(url, username, password)) {
            String sql = "SELECT column1, column2, column3 FROM mytable";
            Statement statement = connection.createStatement();
            ResultSet resultSet = statement.executeQuery(sql);

            // 遍历结果集并将数据放入HashMap
            while (resultSet.next()) {
                String key = resultSet.getString("column1");
                String value = resultSet.getString("column2");
                String anotherValue = resultSet.getString("column3");
                hashMap.put(key, value + ", " + anotherValue);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }

        // 输出HashMap中的数据
        for (String key : hashMap.keySet()) {
            System.out.println("Key: " + key + ", Value: " + hashMap.get(key));
        }
    }
}