solution:
this works:
String p="<pre>[\\\\w\\\\W]*</pre>";
I want to match and capture the enclosing content of the <pre></pre> tag
tried the following, not working, what's wrong?
String p="<pre>.*</pre>";
Matcher m=Pattern.compile(p,Pattern.MULTILINE|Pattern.CASE_INSENSITIVE).matcher(input);
if(m.find()){
String g=m.group(0);
System.out.println("g is "+g);
}
Regex is in fact not the right tool for this. Use a parser. Jsoup is a nice one.
Document document = Jsoup.parse(html);
for (Element element : document.getElementsByTag("pre")) {
System.out.println(element.text());
}
The parse() method can also take an URL or File by the way.
The reason I recommend Jsoup is by the way that it is the least verbose of all HTML parsers I tried. It not only provides JavaScript like methods returning elements implementing Iterable, but it also supports jQuery like selectors and that was a big plus for me.
You want the DOTALL flag, not MULTILINE. MULTILINE changes the behavior of the ^ and $, while DOTALL is the one that lets . match line separators. You probably want to use a reluctant quantifier, too:
String p = "<pre>.*?</pre>";
String stringToSearch = "H1 FOUR H1 SCORE AND SEVEN YEARS AGO OUR FATHER...";
// the case-insensitive pattern we want to search for
Pattern p = Pattern.compile("H1", Pattern.CASE_INSENSITIVE);
Matcher m = p.matcher(stringToSearch);
// see if we found a match
int count = 0;
while (m.find())
count++;
System.out.println("H1 : "+count);
Related
I'm using the following regex:
(?<=<((Pswrd>)|([^/]{1,2147483646}?:Pswrd>)))((?s).+?)(?=</(\\1))
And I have the following text to match:
<abc:Pswrd>PASSWORD_ONE</abc:Pswrd>
<Pswrd>PASSWORD_TWO</Pswrd>
I need to match the context of both XML tags but is only working for the second one.
The output is:
PASSWORD_TWO
And it should be:
PASSWORD_ONE
PASSWORD_TWO
It seems the OR is not working for some reason?
String message = " <abc:Pswrd>PASSWORD_ONE</abc:Pswrd>\n" +
" <Pswrd>PASSWORD_TWO</Pswrd>";
String regex = "(?<=<((Pswrd>)|([^/]{1,2147483646}?:Pswrd>)))((?s).+?)(?=</(\\1))";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(message);
while (matcher.find()) {
String group = matcher.group();
System.out.println(group);
}
Thanks
Update: It needs to be the matching group 0.
So in order to either match <Pswd> or <abc:Pswd> or <something:Pswd>, the RegEx would need to look something like <\w*:*Pswrd>. The problem however is that the look behind does not like non-fixed width quantifiers, so you can't create a look behind that caters for a "dynamic"
Instead I would suggest just go for something simple, such as :
(?<=Pswrd>)(.*)(?=<\/)
Essentially here you just look for the last bit of the opening tag (namely "Pswrd>") then you match any thing between that and the closing portion of the tag.
I've tried a few methods (jsoup shown below) to turn & into & only in links. The difficulty I'm encountering suggests I'm going about this all wrong. I suspect I'll be facepalming when solutions are offered, but maybe good old regex is the best answer (as I need to only do the replacing in hrefs) unless the reader code is modified?
The parsing libraries (also tried NekoHTML) want to convert all &s to & so I'm having trouble using them to even get the true link hrefs with which to use String's replace method.
Input:
String toParse = "The Link with an encoded ampersand (&) is challenging."
Desired output:
The Link with an encoded ampersand (&) is challenging.
I'm encountering this trying to read an RSS feed that is rendering <link>s with & instead of &.
Update
I ended up using regex to identify the links, then using replace to insert a decoded link in place of the one with &s. Pattern.quote() turned out to be very handy, but I had to manually close and re-open the quoted portions so I could regex or my ampersand condition:
final String cleanLink = StringUtils.strip(link).replaceAll(" ", "%20").replaceAll("'", "%27");
String regex = Pattern.quote(link);
// end and re-start literal matching around my or condition
regex = regex.replaceAll("&", "\\\\E(&|&)\\\\Q");
final Pattern pattern = Pattern.compile(regex);
final Matcher matcher = pattern.matcher(result);
while (matcher.find()) {
int index = result.indexOf(matcher.group());
while (index != -1) {
// this replaces the links with & with the same links with &
// because cleanLink is from the DOM and has been properly decoded
result.replace(index, index + matcher.group().length(), cleanLink);
index += cleanLink.length();
index = result.indexOf(matcher.group(), index);
linkReplaced = true;
}
}
I'm not thrilled with this approach, but I had to handle too many conditions myself without using a DOM tool to identify links.
Have a look at the StringEscapeUtils. Try unescapeHtml() on your String.
I am trying to parse out data from a HTML page using a Java RegEx but have not had much luck. The data is dynamic and often includes zero to many instances of spaces, tabs, new lines. Also, depending on the number of hits the structure of the string I'm parsing may change. Here is a sample in the cleanest format:
<div class="center">Showing 25 of 2,343,098 (search took 1.245 seconds)</div>
However it can also look like this:
<div class="center">Showing 2343098 (search took 1.245 seconds)</div>
or
<div class="center">
Showing 125
of 2,343,098
(search took 1.245 seconds)</div>
What I'm trying to parse is the 2,343,098 but since the pages is HTML I have to use either "Showing" or "(search took" to search between. The spaces, tabs and new lines are tripping me up and I've been trying to use lookahead & lookbehind but so far no luck. Here are a few patterns I've tried
String pattern1 = "Showing [0-9]*\\S"; // not useful
String pattern2 = "[[\\d,+\\.?\\d+]*[\\s*\\n]\\(search took"; //fails
String pattern3 = "(/i)(Showing)(.+?)(\\(search took)"; //fails
String pattern4 = "([\\s\\S]*)\\(search took"; //fails
String pattern5 = "(?s)[\\d].*?(?=\\(search took)"; //close...but fails
Pattern pattern = Pattern.compile(pattern5);
Matcher matcher = pattern.matcher(text); // text = the string I'm parsing
while(matcher.find()) {
System.out.println(matcher.group(0));
}
HTML is not a regular language, and cannot be accurately parsed using regular expressions. Regex-based solutions are likely to break when the format of the markup changes in future, but a parser-based solution will be more accurate.
However, if this is a one-off job, you can get away with the following regex:
Showing\s+(?:\d+\s+of\s+)?([\d,.]+)\s+\(search
Demo
The examples suggest
"Showing\\s+\\d+\\s+(of\\s+[\\d,.]+\\s+)?\\(search"
I'm writing a utility to extract the names of header files from JSPs. I have no problem reading the JSPs line by line and finding the lines I need. I am having a problem extracting the specific text needed using regex. After looking at many similar questions I'm hitting a brick wall.
An example of the String I'll be matching from within is:
<jsp:include page="<%=Pages.getString(\"MY_HEADER\")%>" flush="true"></jsp:include>
All I need is MY_HEADER for this example. Any time I have this tag:
<%=Pages.getString
I need what comes between this:
<%=Pages.getString(\" and this: )%>
Here is what I have currently (which is not working, I might add) :
String currentLine;
while ((currentLine = fileReader.readLine()) != null)
{
Pattern pattern = Pattern.compile("<%=Pages\\.getString\\(\\\\\"([^\\\\]*)");
Matcher matcher = pattern.matcher(currentLine);
while(matcher.find()) {
System.out.println(matcher.group(1).toString());
}}
I need to be able to use the Java RegEx API and regex to extract those header names.
Any help on this issue is greatly appreciated. Thanks!
EDIT:
Resolved this issue, thankfully. The tricky part was, after being given the right regex, it had to be taken into account that the String I was feeding to the regex was always going to have two " / " characters ( (/"MY_HEADER"/) ) that needed to be escaped in the pattern.
Here is what worked (thanks to the help ;-)):
Pattern pattern = Pattern.compile("<%=Pages\\.getString\\(\\\\\"([^\\\\\"]*)");
This should do the trick:
<%=Pages\\.getString\\(\\\\\"([^\\\\]*)
Yeah that's a scary number of back slashes. matcher.group(1) should return MY_HEADER. It starts at the \" and matches everything until the next \ (which I assume here will be at \")%>.)
Of course, if your target text contains a backslash (\), this will not work. But you didn't give an indication that you'd ever be looking for something like <%=Pages.getString(\"Fun!\Yay!\")%> -- where this regex would only return Fun! and ignore the rest.
EDIT
The reason your test case was failing is because you were using this test string:
String currentLine = "<%=Pages.getString(\"MY_HEADER\")%>";
This is the equivalent of reading it in from a file and seeing:
<%=Pages.getString("MY_HEADER")%>
Note the lack of any \. You need to use this instead:
String sCurrentLine = "<%=Pages.getString(\\\"MY_HEADER\\\")%>";
Which is the equivalent of what you want.
This is test code that works:
String currentLine = "<%=Pages.getString(\\\"MY_HEADER\\\")%>";
Pattern pattern = Pattern.compile("<%=Pages\\.getString\\(\\\\\"([^\\\\]*)");
Matcher matcher = pattern.matcher(currentLine);
while(matcher.find()) {
System.out.println(matcher.group(1).toString());
}
How do I match an URL string like this:
img src = "https://stackoverflow.com/a/b/c/d/someimage.jpg"
where only the domain name and the file extension (jpg) is fixed while others are variables?
The following code does not seem working:
Pattern p = Pattern.compile("<img src=\"http://stachoverflow.com/.*jpg");
// Create a matcher with an input string
Matcher m = p.matcher(url);
while (m.find()) {
String s = m.toString();
}
There were a couple of issues with the regex matching the sample string you gave. You were close, though. Here's your code fixed to make it work:
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class TCPChat {
static public void main(String[] args) {
String url = "<img src=\"http://stackoverflow.com/a/b/c/d/someimage.jpg\">";
Pattern p = Pattern.compile("<img src=\"http://stackoverflow.com/.*jpg\">");
// Create a matcher with an input string
Matcher m = p.matcher(url);
while (m.find()) {
String s = m.toString();
System.out.println(s);
}
}
}
First, I would use the group() method to retrieve the matched text, not toString(). But it's probably just the URL part you want, so I would use parentheses to capture that part and call group(1) retrieve it.
Second, I wouldn't assume src was the first attribute in the <img> tag. On SO, for example, it's usually preceded by a class attribute. You want to add something to match intervening attributes, but make sure it can't match beyond the end of the tag. [^<>]+ will probably suffice.
Third, I would use something more restrictive than .* to match the unknown part to the path. There's always a chance that you'll find two URLs on one line, like this:
<img src="http://so.com/foo.jpg"> blah <img src="http://so.com/bar.jpg">
In that case, the .* in your regex would bridge the gap, giving you one match where you wanted two. Again, [^<>]* will probably be restrictive enough.
There are several other potential problems as well. Are attribute values always enclosed in double-quotes, or could they be single-quoted, or not quoted at all? Will there be whitespace around the =? Are element and attribute names always lowercase?
...and I could go on. As has been pointed out many, many times here on SO, regexes are not really the right tool for working with HTML. They can usually handle simple tasks like this one, but it's essential that you understand their limitations.
Here's my revised version of your regex (as a Java string literal):
"(?i)<img[^<>]+src\\s*=\\s*[\"']?(http://stackoverflow\\.com/[^<>]+\\.jpg)"