Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gm

Test String

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "--([a-z\\d]+)-A--[\\s\\S]+?--\\1-Z--"; final String string = "--f15a0000-A--\n" + "[30/Aug/2018:14:06:33 +0200] W4fdyYHC0Xb8YDuIqk5YQgAAAD0 127.0.0.1 55454 127.0.0.1 80\n" + "--f15a0000-B--\n" + "GET /FormValidation/page1.php HTTP/1.1\n" + "Host: localhost\n" + "Connection: keep-alive\n" + "Upgrade-Insecure-Requests: 1\n" + "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36\n" + "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8\n" + "Referer: http://localhost/FormValidation/\n" + "Accept-Encoding: gzip, deflate, br\n" + "Accept-Language: en-US,en;q=0.9\n" + "tanuser: 00198343\n\n" + "--f15a0000-F--\n" + "HTTP/1.1 200 OK\n" + "X-Powered-By: PHP/5.6.35\n" + "Content-Length: 851\n" + "Keep-Alive: timeout=5, max=99\n" + "Connection: Keep-Alive\n" + "Content-Type: text/html; charset=UTF-8\n\n" + "--f15a0000-Z--\n\n" + "--bb410000-A--\n" + "[30/Aug/2018:14:06:37 +0200] W4fdzYHC0Xb8YDuIqk5YQwAAAD0 127.0.0.1 55454 127.0.0.1 80\n" + "--bb410000-B--\n" + "POST /FormValidation/validation.php HTTP/1.1\n" + "Host: localhost\n" + "Connection: keep-alive\n" + "Content-Length: 33\n" + "Accept: */*\n" + "Origin: http://localhost\n" + "X-Requested-With: XMLHttpRequest\n" + "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36\n" + "Content-Type: application/x-www-form-urlencoded; charset=UTF-8\n" + "Referer: http://localhost/FormValidation/page1.php\n" + "Accept-Encoding: gzip, deflate, br\n" + "Accept-Language: en-US,en;q=0.9\n" + "tanuser: 00198343\n\n" + "--bb410000-C--\n" + "name1=test&email1=ssn%40gmail.com\n" + "--bb410000-F--\n" + "HTTP/1.1 200 OK\n" + "X-Powered-By: PHP/5.6.35\n" + "Content-Length: 17\n" + "Keep-Alive: timeout=5, max=98\n" + "Connection: Keep-Alive\n" + "Content-Type: text/html; charset=UTF-8\n\n" + "--bb410000-Z--"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html