code: public static String linkTagAction(String target, ServletRequest req) {
  
          return linkTagAction(target, req, null);
      }
docs: Returns a link to a file in the OpenCms VFS
  that has been adjusted according to the web application path and the
  OpenCms static export rules.<p>
  
  The current OpenCms user context URI will be used as source of the link.</p>
  
  Since OpenCms version 7.0.2, you can also use this method in case you are not sure
  if the link is internal or external, as
  {@link CmsLinkManager#substituteLinkForUnknownTarget(org.opencms.file.CmsObject, String)}
  is used to calculate the link target.<p>
  
  Relative links are converted to absolute links, using the current element URI as base.<p>
  
  @param target the link that should be calculated, can be relative or absolute
  @param req the current request
  
  @return the target link adjusted according to the web application path and the OpenCms static export rules
  
  @see org.opencms.staticexport.CmsLinkManager#substituteLinkForUnknownTarget(org.opencms.file.CmsObject, String)