Java regular expression, Regular Expression

Java regular expression, Regular Expression
Java Regular Expression

Regular Expression

1. Two classes are provided in the java. util. regex package to support regular expressions. 1. Matcher: Engine for matching character sequence by interpreting Pattern

Public final class Matcher implements MatchResult

2. Pattern: Expression of Regular Expression Compilation

Public final class Pattern implements java. io. Serializable

 

Code:

Package yuki. regular; import java. util. regex. matcher; import java. util. regex. pattern; public class FirstTest {public static void main (String [] args) {/*** Pattern. The regular expression is compiled in the form of * public final class Pattern implements java. io. serializable */String str = "hi! I am a tony; gglad to see you! "; String regex =" \ p {Punct} "; Pattern pattern = Pattern. compile (regex); String [] strArr = pattern. split (str); for (int I = 0; I <strArr. length; ++ I) System. out. println ("strArr [" + I + "] =" + strArr [I]);/*** Matcher, by interpreting Pattern, perform the matching operation on character sequence * public final class Matcher implements MatchResult */Matcher matcher = pattern. matcher (str); System. out. println (matcher. matches ()? "Match": "mismatch"); System. out. println (Pattern. compile ("\ p {Punct} + "). matcher (".,.; "). matches ()? "Match": "do not match"); String s2 = "yuki@gmail.com"; Pattern p2 = Pattern. compile ("\ w + @ \ w +. [a-zA-Z] + "); Matcher m2 = p2.matcher (s2); System. out. println ("m2.matches () =" + m2.matches ());}}

 

 

Running result:

StrArr [0] = histrArr [1] = I am a tonystrArr [2] = gglad to see that you do not match m2.matches () = true

 

 

2. Regular Expressions supported by the String class

Code:

Package yuki. regular; import java. util. regex. matcher; import java. util. regex. pattern; public class SecondTest {public static void main (String [] args) {/*** match and replace */String date = "2015/2/27"; Pattern p = Pattern. compile ("/"); Matcher m = p. matcher (date); String s = m. replaceAll ("-"); System. out. println ("m. matches () = "+ m. matches (); System. out. println ("s =" + s); System. out. println ("m. replaceFirst (\ "-\") = "+ m. replaceFirst ("-"); // match the phone number String phone = "0755-28792686 "; string regex = "\ d {3, 4}-\ d {7, 8}"; boolean isPhone = phone. matches (regex); System. out. println ("isPhone =" + isPhone );}}

 

Running result:

m.matches() = falses = 2015-2-27m.replaceFirst("-") = 2015-2/27isPhone = true

 

3. Common examples

Code:

Package yuki. regular; public class ThirdTest {public static void main (String [] args) {/*** contains at least one of the strings */String s = "123,456,789,012,345 "; string s2 = "123,456,789,013,345"; String regex = ". * (234 | 678 | 012 ). * "; boolean isMatch = s. matches (regex); boolean isMatch2 = s2.matches (regex); System. out. println ("isMatch =" + isMatch); System. out. println ("isMatch2 =" + isMatch2); // matching amount String price = "499.00"; System. out. println ("price. matches (\ "\ d +. \ d + \ ")" + price. matches ("\ d +. \ d + "));}}

 

Running result:

isMatch = trueisMatch2 = falseprice.matches("\d+.\d+")true

 

For more information, see:
API: java. util. regex
Ma Jianwei _ JAVA basics _ Regular Expressions

 

Click the red button belowFollow meRight!
Kong Dongyang
February 27, year 15
Http://www.cnblogs.com/kodoyang/