public void acessaSistema(){
        
        try{
        ConexaoBD conexao = new ConexaoBD();
        conexao.conectar();
        conexao.st = conexao.conn.createStatement();
        
        String sql = "SELECT * FROM LOGIN";
        
        conexao.rs = conexao.st.executeQuery(sql);
        conexao.rs.first();
        
        if(txtUsuario.getText().equals(conexao.rs.getString("Nome")) && txtSenha
                .getText().equals(conexao.rs.getString("Senha"))) {
        }else {
           }
        }catch (SQLException e){
            System.out.println("Erro: " +e.getMessage());  
        }
        if (txtUsuario.getText().equals("admin")){
            Principal2 p2 = new Principal2();
            p2.show();
            dispose();
            
        }else{
            Principal p1 = new Principal();
            p1.show();
            dispose();
        }
    }