1. A method comprising: acquiring a preset character string; acquiring a to-be-collected character string in the preset character string in response to a trigger instruction; recognizing a character string before the to-be-collected character string from the preset character string, the character string before the to-be-collected character string being used as a first character string; recognizing a character string after the to-be-collected character string from the preset character string, the character string after the to-be-collected character string being used as a second character string; and generating a regular expression of the to-be-collected character string by a first preset rule according to character features of the to-be-collected character string, the first character string, and the second character string.