how to unescape XML in java

Question

I need to unescape a xml string containing escaped XML tags:

< > & etc... 

I did find some libs that can perform this task, but i'd rather use a single method that can perform this task.

Can someone help?

cheers, Bas Hendriks

Answer 1

StringEscapeUtils.unescapeXml(xml) 

(commons-lang, download)

Answer 2

Here's a simple method to unescape XML. It handles the predefined XML entities and decimal numerical entities (&#nnnn;). Modifying it to handle hex entities (&#xhhhh;) should be simple.

public static String unescapeXML( final String xml ) {     Pattern xmlEntityRegex = Pattern.compile( "&(#?)([^;]+);" );     //Unfortunately, Matcher requires a StringBuffer instead of a StringBuilder     StringBuffer unescapedOutput = new StringBuffer( xml.length() );      Matcher m = xmlEntityRegex.matcher( xml );     Map<String,String> builtinEntities = null;     String entity;     String hashmark;     String ent;     int code;     while ( m.find() ) {         ent = m.group(2);         hashmark = m.group(1);         if ( (hashmark != null) && (hashmark.length() > 0) ) {             code = Integer.parseInt( ent );             entity = Character.toString( (char) code );         } else {             //must be a non-numerical entity             if ( builtinEntities == null ) {                 builtinEntities = buildBuiltinXMLEntityMap();             }             entity = builtinEntities.get( ent );             if ( entity == null ) {                 //not a known entity - ignore it                 entity = "&" + ent + ';';             }         }         m.appendReplacement( unescapedOutput, entity );     }     m.appendTail( unescapedOutput );      return unescapedOutput.toString(); }  private static Map<String,String> buildBuiltinXMLEntityMap() {     Map<String,String> entities = new HashMap<String,String>(10);     entities.put( "lt", "<" );     entities.put( "gt", ">" );     entities.put( "amp", "&" );     entities.put( "apos", "'" );     entities.put( "quot", "\"" );     return entities; }