// Data Assist Object
public class DAO {

    static String jdbcurl;
    static String username;
    static String password;

    static{
        try {
            Class.forName("com.mysql.jdbc.Driver");
            ResourceBundle rb = ResourceBundle.getBundle("db");
            jdbcurl = rb.getString("jdbcurl");
            username = rb.getString("username");
            password = rb.getString("password");
        } catch (ClassNotFoundException ex) {
            ex.printStackTrace();
        }
    }

    // for insert, delete and update
    public int modify(String sql, String[] args){
        int x=0;
        try(Connection con = DriverManager.getConnection( jdbcurl,username ,password);
            PreparedStatement ps = con.prepareStatement(sql);){

            for (int i = 0; i < args.length; i++) {
                ps.setString(i+1, args[i]);
            }

            x =ps.executeUpdate();
            System.out.println(x);

        }catch(SQLException e){
            e.printStackTrace();
        }
        return x;
    }

    // for select
    public List<Map<String,String>> query(String sql, String[] params){

        List<Map<String,String>> resList = new ArrayList<>();
        try(Connection con = DriverManager.getConnection( jdbcurl,username ,password);
            PreparedStatement ps = con.prepareStatement(sql);){

            for (int i = 0; i < params.length; i++) {
                ps.setString(i+1, params[i]);
            }

            try(ResultSet res =ps.executeQuery();){

                ResultSetMetaData mdata = res.getMetaData();
                int num = mdata.getColumnCount();
                while(res.next()){
                    HashMap<String,String> data = new HashMap<>();
                    for (int i = 1; i <= num; i++) {
                        String result = res.getString(i);
                        String columnName = mdata.getColumnName(i);
                        data.put(columnName,result);
                    }
                    resList.add(data);
                }
            }

        }catch(Exception e){
            e.printStackTrace();
        }
        return resList;
    }

    public static void main(String[] args) throws SQLException {
        DAO dao = new DAO();

        String sql = "insert into person(name,tel,birthday,address) values(?,?,?,?)";

        sql = "select ?,?,?,?,? from person";
        List<Map<String,String>> res = dao.query(sql, new String[]{"no","name","tel","birthday","address"});

        for(Map m:res){
            System.out.print("no: "+m.get("no")+",");
            System.out.print("name: "+m.get("name")+",");
            System.out.print("tel: "+m.get("tel")+",");
            System.out.print("birthday: "+m.get("birthday")+",");
            System.out.println("address: "+m.get("address"));
        }

    }
}