title: xs:String in xs:DateTime format to XMLGregorianCalendar
body: <p>I use JAXB for un/marshaling XML messages which I get from server. Usually I get the XMLGregorianCalendar values in the fields, that are defind as xs:dateTime in the describing XSD files, so the conversion to XMLGregorianCalendar is done automatically by JAXB.</p>
  
  <p>Example from XSD file</p>
  
  <pre><code>&lt;xs:attribute name="readouttime" use="required" type="xs:dateTime" /&gt;
  </code></pre>
  
  <p>However one field is defined as xs:string like this:</p>
  
  <pre><code>&lt;xs:element minOccurs="1" maxOccurs="1" name="Value" type="xs:string" /&gt;
  </code></pre>
  
  <p>but I am receiving a value that should represent the dateTime:</p>
  
  <pre><code>&lt;Value&gt;2014-08-31T15:00:00Z&lt;/Value&gt;
  </code></pre>
  
  <p>Is there any nice way, how to convert this string to XMLGregorianCallendar, or should I use SimpleDateFormat and type the pattern manually? I feel this may be a dangerous part.</p>