I have two methods to do a validation like leave in only one?

Question

connection class:

public class ConnectionFactory {

    private static final String DRIVER = "com.mysql.jdbc.Driver";
    private static final String URL = "jdbc:mysql://localhost:3306/helpsemeq"+"?verifyServerCertificate=false&useSSL=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=America/Sao_Paulo";
    private static final String USER = "root";
    private static final String PASS = "";
    private static Connection conexao;
    public Statement statement;
    public ResultSet resultset;

    public boolean getConnection() {
        boolean result = true;
        try {
            Class.forName(DRIVER);
            conexao = DriverManager.getConnection(URL, USER, PASS);
            result = true;
        } catch (ClassNotFoundException | SQLException ex) {
            result = false;
            throw new RuntimeException("Erro na conexão: ", ex);
        }
        return result;
    }

    public static void closeConnection(Connection con) {
        try {
            if (con != null) {
                con.close();
            }
        } catch (SQLException ex) {
            Logger.getLogger(ConnectionFactory.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public static void closeConnection(Connection con, PreparedStatement stmt) {
        closeConnection(con);
        try {
            if (stmt != null) {
                stmt.close();
            }
        } catch (SQLException ex) {
            Logger.getLogger(ConnectionFactory.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public static void closeConnection(Connection con, PreparedStatement stmt, ResultSet rs) {
        closeConnection(con, stmt);
        try {
            if (rs != null) {
                rs.close();
            }
        } catch (SQLException ex) {
            Logger.getLogger(ConnectionFactory.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public void executeSQL(String sql) {
        try {
            statement = conexao.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            resultset = statement.executeQuery(sql);
        } catch (SQLException sqlex) {
            System.out.println("Não foi possivel executar o comando: \n" + sqlex + "\n o sql passado foi: \n" + sql);
        }
    }
}

here is the method that is in the connection class to run the query:

public void executeSQL(String sql) {
        try {
            statement = conexao.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
            resultset = statement.executeQuery(sql);
        } catch (SQLException sqlex) {
            System.out.println("Não foi possivel executar o comando: \n" + sqlex + "\n o sql passado foi: \n" + sql);
        }
    }

the other method that gets inside the jframe:

public void validaLogin(){
        try {
            ConnectionFactory conn = new ConnectionFactory();
            conn.getConnection();

            String sql = "SELECT login,senha FROM usuario where login = '" + jTextField1.getText() + "' and  senha = '" + jTextField2.getText() + "'";
            conn.executeSQL(sql);

            //Se houver resultado, ou seja, se validar o usuario e senha, faça algo.
            if (conn.resultset.next()) {
                new NewJFrame1().setVisible(true);
                dispose();
            } else {
                System.out.println("Acesso negado.");
            }
        }catch(SQLException e){
            System.out.println("Erro: "+e);
        }
    }

it would be possible to do all this in just one method?

Answer 1

I think it’s really cool your code. My suggestion is to create two more classes. User and User

A User object will be used to store the id.

An object of the User type will be responsible for accessing the database using the Connectionfactory you created. An example would be:

class Usuario {
    Long id;
    public Usuario(Long id) {
        this.id = id;
    }
}

class UsuarioDAO {

    private ConnectionFactory connectionFactory;

    public UsuarioDAO {
        this.connectionFactory = connectionFactory;    
    }

    public User autentica(String login, String senha) {
        String query = ...// O código para montar a query
        this.connectionFactory.getConnection();
        this.connectionFactory.executeSql(query);
        ResultSet rs = this.connectionFactory.resultset;
        if (rs.next()) {
            Usuario usuario = new Usuario(rs.getLong("id"));
            return usuario;
        }
        return null; //Se for null, quer dizer que não foi possível autenticar
    }
}

And so, in Jframe you use the user.

It’s nice to do this separation to make your code less coupled and more cohesive. It has some principles of Object-Oriented Programming that deal with coupling and cohesion. DRY, SOLID, Tell Don’t Ask are some. Worth a look at!

On BD access indications, I suggest the same google. Search for JDBC(Java Database Connectivity) that you will find many subjects, frameworks and library to work with.

Good luck!