Java Regex或XML解析器？

Question

I want to remove any tags such as

<p>hello <namespace:tag : a>hello</namespace:tag></p>

to become

 <p> hello hello </p>

What is the best way to do this if it is regex for some reason this is now working can anyone help?

(<|</)[:]{1,2}[^</>]>

edit: added

Answer 1

Definitely use an XML parser. Regex should not be used to parse *ML

Answer 2

You should not use regex for these purposes use a parser like lxml or BeautifulSoup

>>> import lxml.html as lxht
>>> myString = '<p>hello <namespace:tag : a>hello</namespace:tag></p>'
>>> lxht.fromstring(myString).text_content()
'hello hello'

Here is a reason why you should not parse html/xml with regex.

Answer 3

If you're just trying to pull the plain text out of some simple XML, the best (fastest, smallest memory footprint) would be to just run a for loop over the data:

PSEUDOCODE BELOW

bool inMarkup = false;
string text = "";
for each character in data // (dunno what you're reading from)
{
    char c = current;
    if( c == '<' ) inMarkup = true;
    else if( c == '>') inMarkup = false;
    else if( !inMarkup ) text += c;
}

Note: This will break if you encounter things like CDATA, JavaScript, or CSS in your parsing.

So, to sum up... if it's simple, do something like above and not a regular expression. If it isn't that simple, listen to the other guys an use an advanced parser.

Answer 4

This is a solution I personally used for a likewise problem in java. The library used for this is Jsoup : http://jsoup.org/ .

In my particular case I had to unwrap tags that had an attribute with a particular value in them. You see that reflected in this code, it's not the exact solution to this problem but could put you on your way.

  public static String unWrapTag(String html, String tagName, String attribute, String matchRegEx) {
    Validate.notNull(html, "html must be non null");
    Validate.isTrue(StringUtils.isNotBlank(tagName), "tagName must be non blank");
    if (StringUtils.isNotBlank(attribute)) {
      Validate.notNull(matchRegEx, "matchRegEx must be non null when an attribute is provided");
    }    
    Document doc = Jsoup.parse(html);
    OutputSettings outputSettings = doc.outputSettings();
    outputSettings.prettyPrint(false);
    Elements elements = doc.getElementsByTag(tagName);
    for (Element element : elements) {
      if(StringUtils.isBlank(attribute)){
        element.unwrap();
      }else{
        String attr = element.attr(attribute);
        if(!StringUtils.isBlank(attr)){
          String newData = attr.replaceAll(matchRegEx, "");
          if(StringUtils.isBlank(newData)){
            element.unwrap();
          }
        }        
      }
    }
    return doc.html();
  }