Regular expressions match any character (including line breaks)--Regular expressions

Today in Java, you want to use a regular expression to get any character in a paragraph of text. So it's very casual to write the following matching rules:
(.*)
After the results are run, the text after the wrapping cannot be obtained. Then I looked up the manual and found the regular expression, "." (dot notation) matches all characters except the newline character "\ n". At the same time, there is a word in the manual: to match any character including ' \ n ', use a pattern like ' [. \ n] '. So I modified the matching rule for the regular expression as follows:
([. \n]*), of course, if you write to a word directly in a Java program, you need to change to ([. \\n]*)
As a result, run the program again, and find out what content is not taken. I am baffled and revise it to the following rules:
([.| \n]*) and ([\ n.] *)
The result is still no, nothing can be obtained. It seems that the point symbol and the line Fu Yi Ober ~
Then the Internet to check, although did not find out what the above rules is where the problem, but found a solution, after a try, can indeed match including line-break characters, any character, the following is the correct regular expression matching rules:
([\s\s]*)
It can also be represented by "([\d\d]*)", "([\w\w]*)".


In a text file, this expression can match all the English
/[ -~]/
This expression can match all non-English (such as Chinese)
/[^ -~]/
/is used in VI. You don't need to be in a editplus or a program.