JSP/Java – strip_tags() PHP like function | Remus Stratulat

Feb 2nd 06 Posted by Remus Stratulat in Java, Others

JSP/Java – strip_tags() PHP like function

Another PHP function that is very used is strip_tags.
This function tries to return a string with all HTML tags stripped from a given string.

   1:      public static String strip_tags(String text, String allowedTags) {

   2:          String[] tag_list = allowedTags.split(",");

   3:          Arrays.sort(tag_list);

4:

   5:          final Pattern p = Pattern.compile("<[/!]?([^\\\\s>]*)\\\\s*[^>]*>",

   6:                  Pattern.CASE_INSENSITIVE);

   7:          Matcher m = p.matcher(text);

8:

   9:          StringBuffer out = new StringBuffer();

  10:          int lastPos = 0;

  11:          while (m.find()) {

  12:              String tag = m.group(1);

  13:              // if tag not allowed: skip it

  14:              if (Arrays.binarySearch(tag_list, tag) < 0) {

  15:                  out.append(text.substring(lastPos, m.start())).append(" ");

16:

  17:              } else {

  18:                  out.append(text.substring(lastPos, m.end()));

  19:              }

  20:              lastPos = m.end();

  21:          }

  22:          if (lastPos > 0) {

  23:              out.append(text.substring(lastPos));

  24:              return out.toString().trim();

  25:          } else {

  26:              return text;

  27:          }

  28:      }

David Sickmiller [Visitor] says:

June 22, 2006 at 10:11 am

You have a mistake with a variable name on line 13. It should be changed to this:
if(Arrays.binarySearch(tag_list, tag) < 0) {

It’s also worth noting that this implementation is case sensitive.
David Sickmiller [Visitor] says:

June 22, 2006 at 10:22 am

Additionally, two backslashes (\\) need to be added before each occurrence of “s” in the regex pattern.
Remus Stratulat [Member] says:

June 22, 2006 at 11:05 am

Thank you for your observations. I’ve corrected them out.

this should work as well.

   1:      public static String stripTags(String text, String allowed) {

   2:          String pattern = "";

   3:          String[] allow = allowed.split(",");

   4:          if (allow.length > 0) {

   5:              StringBuffer sb = new StringBuffer();

   6:              sb.append(allow[0]);

   7:              for (int i = 1; i < allow.length; i++) {

   8:                  sb.append("|");

   9:                  sb.append(allow[i]);

  10:              }

  11:              pattern = "";

  12:          } else {

  13:              pattern = "";

  14:          }

  15:          return text.replaceAll(pattern, "");

  16:      }