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Possible Duplicate:
Java: How to decode HTML character entities in Java like HttpUtility.HtmlDecode?
I need to extract paragraphs (like title in StackOverflow) from an html file.
I can use regular expressions in Java to extract the fields I need but I have to decode the fields obtained.
EXAMPLE
field extracted:
Paging Lucene's search results (with **;** among **'** and **s**)
field after decoding:
Paging Lucene's search results
Is there any class in java that will allow me to convert these html codes?
2 Answers
Use methods provided by Apache Commons Lang
import org.apache.commons.lang.StringEscapeUtils;
// ...
String afterDecoding = StringEscapeUtils.unescapeHtml(beforeDecoding);
Do not try to solve everything by regexp.
While you can do some parts - such as replacing entities, the much better approach is to actually use a (robust) HTML parser.
See this question: RegEx match open tags except XHTML self-contained tags for why this is a bad idea to do with the regexp swiss army chainsaw. Seriously, read this question and the top answer, it is a stack overflow highlight!
Chuck Norris can parse HTML with regex.
The bad news is: there is more than one way to encode characters.
For example, the character 'λ' can be represented as
λ,λorλ
And if you are really unlucky, some web site relies on some browsers capabilities to guess character meanings. ™ for example is not valid, yet many browsers will interpret it as ™.
Clearly it is a good idea to leave this to a dedicated library instead of trying to hack a custom regular expression yourself.
So I strongly recommend:
- Feed string into a robust HTML parser
- Get parsed (and fully decoded) string back
