java正则表达式

 

1

Regular Expression Description

.	Matches any character
^regex	Finds regex that must match at the beginning of the line.
regex$	Finds regex that must match at the end of the line.
[abc]	Set definition, can match the letter a or b or c.
[abc][vz]	Set definition, can match a or b or c followed by either v or z.
[^abc]	When a caret appears as the first character inside square brackets, it negates the pattern. This can match any character except a or b or c.
[a-d1-7]	Ranges: matches a letter between a and d and figures from 1 to 7, but not d1.
X|Z	Finds X or Z.
XZ	Finds X directly followed by Z.
$	Checks if a line end follows.

2

Regular Expression Description

\d	Any digit, short for [0-9]
\D	A non-digit, short for [^0-9]
\s	A whitespace character, short for [ \t\n\x0b\r\f]
\S	A non-whitespace character, short for [^\s]
\w	A word character, short for [a-zA-Z_0-9]
\W	A non-word character [^\w]
\S+	Several non-whitespace characters
\b	Matches a word boundary where a word character is [a-zA-Z0-9_].

3

Regular Expression Description Examples

*	Occurs zero or more times, is short for {0,}	X* finds no or several letter X, .* finds any character sequence
+	Occurs one or more times, is short for {1,}	X+ - Finds one or several letter X
?	Occurs no or one times, ? is short for {0,1}.	X? finds no or exactly one letter X
{X}	Occurs X number of times, {} describes the order of the preceding liberal	\d{3} searches for three digits, .{10} for any character sequence of length 10.
{X,Y}	Occurs between X and Y times,	\d{1,4} means \d must occur at least once and at a maximum of four.
*?	? after a quantifier makes it a reluctant quantifier. It tries to find the smallest match.

4

s.matches("regex")	Evaluates if "regex" matches s. Returns only true if the WHOLE string can be matched.
s.split("regex")	Creates an array with substrings of s divided at occurrence of "regex". "regex" is not included in the result.
s.replace("regex"), "replacement"	Replaces "regex" with "replacement