[SOLVED] java regex for links:

trscookie · 03-22-2011, 08:05 AM

Hello all,

Im trying to extract the href of a <link> tag from a html page however as some links contain further preferences I seem to be unable to extract them, do you have any idea how I can write this:

Link:

PHP Code:


			
<link rel="stylesheet" type="text/css" media="screen,print" href="Home_files/Home.css" />

regex:

Code:

"(?i)<link\\s*href="

trying to extract the Home_files/Home.css, thanks in advance.

trscookie

Snark1994 · 03-22-2011, 08:18 AM

You need to add to the regex, then extract a group. This is from memory, so just a rough approach:

Code:

Pattern p = Pattern.compile("<link.*?href=\"(.*)\".*?/>");
Matcher m = p.matcher("<link rel="stylesheet" type="text/css" media="screen,print" href="Home_files/Home.css" />");

if (m.find()) {
    System.out.println(m.group(1));
}

This should print out the first group - in your case, the bit between the two quotes after the 'href' in a 'link' tag

Again, it's untested, but you should be able to adapt it so that it works

Hope this helps,

trscookie · 03-22-2011, 12:25 PM

Ah, just got another quick question for some reason my regex is skipping one image:

Regex:

Code:

"(?i)<img(.*?)src\\s*=\\s*[\"'](.*?)[\"']"

Finding images:

Code:

Image Found: Home_files/logonew.png
Image Found: Home_files/shapeimage_1.png
Image Found: Home_files/shapeimage_2.jpg

But not finding this one:

Code:

:<img src="Home_files/logonew.png" alt="" style="border: none; height: 425px; width: 230px; " />
:<img usemap="#map1" id="shapeimage_1" src="Home_files/shapeimage_1.png" 
style="border: none; height: 359px; left: -6px; position: absolute; top: -5px; width: 226px; z-index: 1;  title="" />
<map name="map1" id="map1">
<area href="" title="" onmouseover="IMmouseover('shapeimage_1', '0');" alt="" 
onmouseout="IMmouseout('shapeimage_1', '0');" shape="rect" coords="11, 207, 177, 225" /></map>
<img style="height: 18px; left: 5px; position: absolute; top: 202px; width: 166px; "
 id="shapeimage_1_link_0" alt="shapeimage_1_link_0" src="Home_files/shapeimage_1_link_0.png" />
: <img src="Home_files/shapeimage_2.jpg" alt="" style="height: 301px; left: 0px; position: absolute; top: 0px; width: 723px; " />

Do you know why it wouldn't find the one in red?

trscookie.

Snark1994 · 03-22-2011, 12:54 PM

Only thing I can see is that it's over 2 lines - it's possible the regex may not match over this... See if moving it all onto one line fixes it

EDIT: Got home and tested it, and yes the newline causes problems

trscookie · 03-22-2011, 01:09 PM

I think that you are right, I have changed it to:

Code:

"(?im)<img(.*?)src\\s*=\\s*[\"'](.*?)[\"']"

however this doesnt seem to have fixed it, is there any other options I can use?

Snark1994 · 03-22-2011, 01:38 PM

Try using 's' instead

trscookie · 03-22-2011, 08:06 PM

Just worked out that its because I have multiple occurrences on the same line, whats the best way I can split that up?

Cheers again,
trscookie.

Snark1994 · 03-23-2011, 11:27 AM

Hm, reading the Matcher docs it looks like you should use the find() method to move onto the next match in the input string

It depends how your code is laid out, though (I'm guessing you're feeding them to the matcher line-by-line?)

trscookie · 03-23-2011, 11:53 AM

humm, tried the .find() option but it would only find one per line, I've cheated a little and split the string at the end of each tag like so: for(String tag : string.split(">")) but it seems to work

cheers for your help

Snark1994 · 03-24-2011, 10:45 AM

No problem

It was nice to dig out java again