title: Add a page number in header in .docx using apache poi
body: <p>I have a text header in my .docx document which is aligned to the left hand side.
  I want to add page number as "Page 1", "Page 2" and so on on the right hand side of the header.I am using Apache POI for the same, is there any possible way to do the same.I am using the below piece of code to add left aligned header -</p>
  
  <pre><code>XWPFDocument document = new XWPFDocument();         
  CTSectPr sectPr = document.getDocument().getBody().addNewSectPr();
  XWPFHeaderFooterPolicy policy = new XWPFHeaderFooterPolicy(document, sectPr);   
  //write header content
  CTP ctpHeader = CTP.Factory.newInstance();
  CTR ctrHeader = ctpHeader.addNewR();
  CTText ctHeader = ctrHeader.addNewT();
  String headerText = "This is a header";
  ctHeader.setStringValue(headerText);    
  XWPFParagraph headerParagraph = new XWPFParagraph(ctpHeader, document);
  XWPFParagraph[] parsHeader = new XWPFParagraph[1];
  parsHeader[0] = headerParagraph;
  policy.createHeader(XWPFHeaderFooterPolicy.DEFAULT, parsHeader);`
  </code></pre>
  
  <p>Please help me with any pointers on this issue.</p>