code: @MatchCode(codes = {301, 302})
      public void visitRedirect(Page page, CrawlDatums next){
          try {
              // page.location() may be relative url path
              // we have to construct an absolute url path
              String redirectUrl = new URL(new URL(page.url()), page.location()).toExternalForm();
              next.addAndReturn(redirectUrl).meta(page.copyMeta());
          } catch (MalformedURLException e) {
              //the way to handle exceptions in WebCollector
              ExceptionUtils.fail(e);
          }
      }
docs: you have to copy it to the added task by "xxxx.meta(page.copyMeta())"