@Override public double getcosttotal() { // TODO Auto-generated method stub try { mysqlimp = new MySqlImp(); String getsum = "SELECT SUM(支出) FROM 利润表"; ResultSet rs = mysqlimp.query(getsum); rs.next(); double result = rs.getDouble(1); rs.close(); return result; } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); return 0; } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); return 0; } }