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java get next few words in string

I am trying to search a .txt file that contains HTML in it. I need to search the file for specific HTML tags, then grab the following next few characters of code. I am new to java, but am willing to learn what I need to.
For example: Say I have the code: <span class="date">Apr 13</span> and all I need is the date(Apr 13). How do I go about doing this?
Thanks a lot!

Have a look at String class docs and try to find the method to search the string.
Since you said you are getting it from a HTML file, you can have a look at Jsoup which is a HTML parser, which will make searching for strings in HTML documents a lot easier.
With jsoup, you can do it like this
File input = new File("input.html");
Document doc = Jsoup.parse(input, "UTF-8", "http://example.com/");
Elements spans = doc.select("span");
for (Element element : spans) {
System.out.println(element.html());
}

try this
Matcher m = Pattern.compile(">(.*?)<").matcher(s);
while(m.find()) {
String s = m.group(1);
}

If you want is something basic (I thought it would be good as you are new), you can use this :
if(s.indexOf("span class=\"date\"")!=0)
s=s.substring(s.indexOf(">")+1,s.lastIndexOf("<"));
But this answer is specific to your question than a broad one

String yourString = "<span class=\"date\">Apr 13</span>"
String date = yourString.split("class=\"date\">")[1].split("</sp")[0];

Parse html string in java servlet

I am trying to parse below string in java servlet.
<con>
<status>OK</status>
<session>12312332432</session>
</con>
I want value of <session> element.
Ideas ?

If it's not XML, you can use regex:
import java.util.regex.*;
String aParser="<con><status>OK</status><session>12312332432</session></con>";
Pattern p=Pattern.compile("<session>(.*)</session>");
Matcher m=p.matcher(aParser);
while(m.find())
{
System.out.println(m.group(1));
}

For XML purposes you should use an XMLParser.
Look at SAXParser it will do the job.
SAXParser is very good when dealing with big files, because the whole document isn´t hold
in memory.

If you just need session value and not the entire XMl data.just split() the string as below
xmlString.split(starttag)[1].split(endtag)[0];

Regex Email addresses out of xml

My question: What's a good way to parse the information below?
I have a java program that gets it's input from XML. I have a feature which will send an error email if there was any problem in the processing. Because parsing the XML could be a problem, I want to have a feature that would be able to regex the emails out of the xml (because if parsing was the problem then I couldn't get the error e-mails out of the xml normally).
Requirements:
I want to be able to parse the to, cc, and bcc attributes seperately
There are other elements which have to, cc, and bcc attributes
Whitespace does not matter, so my example may show the attributes on a newline, but that's not always the case.
The order of the attributes does not matter.
Here's an example of the xml:
<error_options
to="your_email#your_server.com"
cc="cc_error#your_server.com"
bcc="bcc_error#your_server.com"
reply_to="someone_else#their_server.com"
from="bo_error#some_server.org"
subject="Error running System at ##TIMESTAMP##"
force_send="false"
max_email_size="10485760"
oversized_email_action="zip;split_all"
>
I tried this error_options.{0,100}?to="(.*?)", but that matched me down to reply_to. That made me think there are probably some cases I might miss, which is why I'm posting this as a question.

This piece will put all attributes from your String s="<error_options..." into a map:
Pattern p = Pattern.compile("\\s+?(.+?)=\"(.+?)\\s*?\"",Pattern.DOTALL);
Map a = new HashMap() ;
Matcher m = p.matcher(s) ;
while( m.find() ) {
String key = m.group(1).trim() ;
String val = m.group(2).trim() ;
a.put(key, val) ;
}
...then you can extract the values that you're interested in from that map.

This question is similar to RegEx match open tags except XHTML self-contained tags. Never ever parse XML or HTML with regular expressions. There are many XML parser implementation in Java to do this task properly. Read the document and parse the attributes one by one.
Don't mind, if the users XML is not well-formed, the parsers can handle a lot of sloppiness.

/<error_options(?=\s)[^>]*?(?<=\n)\s*to="([^"]*)"/s;
/<error_options(?=\s)[^>]*?(?<=\n)\s*cc="([^"]*)"/s;
/<error_options(?=\s)[^>]*?(?<=\n)\s*bcc="([^"]*)"/s;

get a set of data from a chat log by using regex and java

I'm writing a Java program where I have to extract some data from a chat log file for a further processing using regex(I am new to regular expressions by the way). The chat log schema is defined as follows:[hh:mm:ss] string.
But the specific lines I would like to extract data are in the form of
[hh:mm:ss] <data1> data2. The data I would like to extract are hh:mm:ss, data1 and data2.
At first, I have tried to extract the time which was easier using
Pattern.compile("(\d{2}:\d{2}:\d{2}).
I have even been able to extract the data1 separately using
Pattern p1=Pattern.compile("<(.*)>"); and it was fine.
But when I try to get "hh:mm:ss",data1 and data2 by using the following regex
Pattern p=Pattern.compile("(\d{2}:\d{2}:\d{2}) <(.*)> (.*)") I have no match found.
So does any one have an Idea on how I can proceed in that case to achieve my goal?

Well if you were matching your own pattern everything would have been fine. You forget about the brackets of the time: [ hh:mm:ss ] . See here:
String text = "22:44:55 <data quite much> data 2";
text = text.replaceAll("(\\d{2}:\\d{2}:\\d{2}) <(.*)> (.*)", "replacement");
System.out.println(text);
text = "[22:44:55] <data quite much> data 2";
text = text.replaceAll("(\\d{2}:\\d{2}:\\d{2}) <(.*)> (.*)", "replacement");
System.out.println(text);
This produces:
replacement
[22:44:55] <data quite much> data 2
So first string was matched and second one - not. Just as expected.
Probably you will just need to change your pattern to \\[(\\d{2}:\\d{2}:\\d{2})\\] <(.*)> (.*).

Convert HTML symbols and HTML names to HTML number using Java

I have an XML which contains many special symbols like ® (HTML number &#174) etc.
and HTML names like &atilde (HTML number &#227) etc.
I am trying to replace these HTML symbols and HTML names with corresponding HTML number using Java. For this, I first converted XML file to string and then used replaceAll method as:
File fn = new File("myxmlfile.xml");
String content = FileUtils.readFileToString(fn);
content = content.replaceAll("®", "&\#174");
FileUtils.writeStringToFile(fn, content);
But this is not working.
Can anyone please tell how to do it.
Thanks !!!

The signature for the replaceAll method is:
public String replaceAll(String regex, String replacement)
You have to be careful that your first parameter is a valid regular expression. The Java Pattern class describes the constructs used in a Java regular expression.
Based on what I see in the Pattern class description, I don't see what's wrong with:
content = content.replaceAll("®", "&\#174");
You could try:
content = content.replaceAll("\\p(®)", "&\#174");
and see if that works better.

I don't think that \# is a valid escape sequence.
BTW, what's wrong with "&#174" ?

If you want HTML numbers try first escaping for XML.
Use EscapeUtils from Apache Commons Lang.
Java may have trouble dealing with it, so first I prefere to escape Java, and after that XML or HTML.
String escapedStr= StringEscapeUtils.escapeJava(yourString);
escapedStr= StringEscapeUtils.escapeXML(yourString);
escapedStr= StringEscapeUtils.escapeHTML(yourString);