Re: java.util.regex.Pattern method matches() fails in this context

From:
Knute Johnson <nospam@rabbitbrush.frazmtn.com>
Newsgroups:
comp.lang.java.help
Date:
Thu, 08 May 2008 15:30:48 -0700
Message-ID:
<4823479a$0$1596$b9f67a60@news.newsdemon.com>
phillip.s.powell@gmail.com wrote:

<%

   String stuff = "<c:import url=\"/common/lib\" context=\"common\" /

";

   if (Pattern.matches("context=\"", stuff)) {
      out.println("the line has a match");
   } else {
      out.println("the line does not have a match");
   }

%>

The following bit of JSP appears to constantly fail no matter how many
times I run it. I am simply looking for the pattern context=" and
replacing it with context="/ throughout an entire String value, but
my regular expression appears to be wrong.

Could someone help me figure out what the right expression would be?

Phil


 From the docs;

  "A matcher is created from a pattern by invoking the pattern's matcher
method. Once created, a matcher can be used to perform three different
kinds of match operations:

     *

       The matches method attempts to match the entire input sequence
against the pattern.
     *

       The lookingAt method attempts to match the input sequence,
starting at the beginning, against the pattern.
     *

       The find method scans the input sequence looking for the next
subsequence that matches the pattern."

So your matches will always fail. You can either modify your regex to
match the entire sequence or use the find() method which searches.

import java.util.regex.*;

public class test {
     public static void main(String[] args) {
         String stuff =
          "<c:import url=\"/common/lib\" context=\"common\" /> >";

         Pattern p = Pattern.compile("context=\"");
         Matcher m = p.matcher(stuff);

         if (m.find()) {
             System.out.println("found");
             System.out.println("start="+m.start());
             System.out.println("end="+m.end());
         }
     }
}

C:\Documents and Settings\Knute Johnson>java test
found
start=28
end=37

--

Knute Johnson
email s/nospam/linux/

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