Java -- Regular Expression-simply finding numbers in strings, java -- Regular Expression

Java -- Regular Expression-simply finding numbers in strings, java -- Regular Expression

import org.junit.Test;import java.util.regex.Matcher;import java.util.regex.Pattern;public class RegexTest {    @Test    public void test(){        String line = "This order was placed for QT3000! OK?";        String pattern = "\\d+";        // Create a Pattern object        Pattern r = Pattern.compile(pattern);        // Now create matcher object.        Matcher m = r.matcher(line);        if (m.find( )) {            System.out.println("Found value: " + m.group() );        } else {            System.out.println("NO MATCH");        }    }}

 

\ D + matches one or more numbers.

The output result is 3000.

 

The following is a regular expression metacharacter Syntax:

Subexpression	Matched
^	Match the beginning of a line
$	Match the end of a row
.	Match any single character except the linefeed. You can also use the m option to allow it to match the linefeed.
[...]	Match any single character in the brackets.
[^...]	Match any single character that is not in parentheses.
\	Start of the entire string
\ Z	End of the entire string
\ Z	The end of the entire string, except the end character of the last line
Re *	Matches 0 or more pre-expression events
Re +	Match one or more previous events
Re?	Matches 0 or 1 items before expressing the event
Re {n}	Match a specified n predicate events
Re {n ,}	Match n or more pre-expression events
Re {n, m}	Events are expressed before matching at least n m pieces
A | B	Match a or B
(Re)	Regular Expression group match text memory
(? : Re)	No regular expression group matching text memory
(?> Re)	Matching independent modes without backtracking
\ W	Match word characters
\ W	Match non-word characters
\ S	Match spaces. Equivalent to [\ t \ n \ r \ f]
\ S	Match non-space characters
\ D	Match a number. It is equivalent to [0-9].
\ D	Match non-Numbers
\	Start of matching string
\ Z	Matches the end of the string. If a new row exists, it matches the previous row.
\ Z	Match the end of a string
\ G	Match where the last match ends
\ N	Return reference capture group number "N"
\ B	Match the word boundary if it is not in parentheses. Match the backspace key in brackets
\ B	Match non-word boundary
\ N, \ t, etc.	Match line breaks, carriage returns, tabs, etc.
\ Q	Start of the referenced character and end with \ E
\ E	End reference starting with \ Q