The correct form of this method is integer. Parseint (stringstr) string. Charat (), the type returned by the method is char, so an error will occur. You can directly model between char and int, and intin = (int) str. charat (index+3);

The statement Integer.parseint () in java is to convert Integer data into basic data type int, Integer is an Integer object, just like String, and int is a basic data type (integer), so Integer.parseint () is to convert the plastic object integer into basic data type int (integer).