Re: newbie Java regexp question

 timjowers <>
Mon, 02 Jul 2007 20:46:26 -0000
On Jul 2, 2:31 pm, "" <> wrote:

Below is a small test program I wrote to try and
do a simple parse of an XML expression, where I
can extract the tag(s) and the data on a single
line. Yes, I know about the other ways to parse
real XML, but I am trying to learn Java only. My
test case is very simple (see below). The problem
seems to be something tricky about the fact that
I am reading the input from the console.

I have tried the regexp in all of the following forms:

        Pattern p1 = Pattern.compile("<(\\S+)>(\\S+)</\\1>");
        Pattern p1 = Pattern.compile("<(\\S+)>(\\S+)</\\1>\n");
        Pattern p1 = Pattern.compile("<(\\S+)>(\\S+)</\\1>\r\n");

In Windows cmd.exe, none of these match when I enter


as standard input.

Any advice would be greatly appreciated.



import java.util.regex.*;

public class test {
    public static void main(String[] args) throws IOException {

    PrintWriter out = null;
    BufferedReader stdIn = null;
        String server = "";
        String userInput;

    stdIn = new BufferedReader(new InputStreamReader(;

    // read arguments
        if(args.length == 1) {
            server = args[0];
        } else {
            System.out.println("no args");

// this one works, but is not really what I want
// Pattern p1 = Pattern.compile("<(\\S+)>(\\S+)<(\\S+)>");

// this one is the correct one that won't match unless the closing tag
// the opening tag, but I cannot get it to work with input from the
        Pattern p1 = Pattern.compile("<(\\S+)>(\\S+)</\\1>\r\n");

        Matcher m1 = p1.matcher("<t1>foo</t1>\r\n");
    System.out.println("matched test string = " + m1.matches());

    while ((userInput = stdIn.readLine()) != null) {

            System.out.println("got user input: " + userInput + " length " +

            // Now see if the pattern matches

            Matcher m = p1.matcher(userInput);

            System.out.println("matched = " + m.matches());

                System.out.println("numGroups found: " + m.groupCount() + "\n");

                // If there were matches, print out the groups found

                if (m.matches()) {

                        for (int j = 1; j <= m.groupCount(); j++) {
                                System.out.println("group " + + " found\n");
                        } // end for
                } // end if

        } // end while


        } // end main

} // end class test

It works.

        Pattern p1 = Pattern.compile("<(\\S+)>(\\S+)</\\1>");

you may be putting a whitespace in the text of the element. Try
revising the regexp to look for anything not the terminator. E.g. this
works as is:

   Yet this does not.
<i>test two</i>


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