title: Tokenize words ignoring hashtags with Open nlp
body: <p>I'm trying to tokenize some sentences. For example the sentences :</p>
  
  <pre><code>String sentence = "The sky is blue. A cat is #blue.";
  </code></pre>
  
  <p>I use the following command with Open nlp:</p>
  
  <pre><code>SimpleTokenizer tokenizer = SimpleTokenizer.INSTANCE;
  String[] result = tokenizer.tokenize(sentence);
  </code></pre>
  
  <p>But I want opennlp considers '<code>#</code>' as a letter of a word. So '<code>#blue#</code>' will be a token.</p>
  
  <p>How to do this ?</p>