public Bd(){
        try{
            Class.forName("com.mysql.jdbc.Driver");
            conexao = DriverManager
                  //  .getConnection("jdbc:mysql://localhost:3306/trabalho","root","aluno");
            .getConnection("jdbc:mysql://localhost:3306/trabalho","root","170737");
            conexao.setAutoCommit(false);//mudar se der erro
        
        } catch (ClassNotFoundException | SQLException ex) {
            Logger.getLogger(Bd.class.getName()).log(Level.SEVERE, null, ex);                    
        }
    }