java sql查询如何选择不带参数的所有数据

import java.sql.*;

public class JavaSQLQueryExample {
    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";

        // SQL查询语句
        String sql = "SELECT * FROM mytable";

        try {
            // 连接数据库
            Connection connection = DriverManager.getConnection(url, username, password);

            // 执行查询
            Statement statement = connection.createStatement();
            ResultSet resultSet = statement.executeQuery(sql);

            // 处理查询结果
            while (resultSet.next()) {
                // 获取每行数据的具体字段值
                int id = resultSet.getInt("id");
                String name = resultSet.getString("name");
                // 其他字段...

                // 处理数据...
            }

            // 关闭连接
            resultSet.close();
            statement.close();
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}