code: public static RootUriTemplateHandler addTo(RestTemplate restTemplate,
  			String rootUri) {
  		Assert.notNull(restTemplate, "RestTemplate must not be null");
  		RootUriTemplateHandler handler = new RootUriTemplateHandler(rootUri,
  				restTemplate.getUriTemplateHandler());
  		restTemplate.setUriTemplateHandler(handler);
  		return handler;
  	}
docs: Add a {@link RootUriTemplateHandler} instance to the given {@link RestTemplate}.
  @param restTemplate the {@link RestTemplate} to add the handler to
  @param rootUri the root URI
  @return the added {@link RootUriTemplateHandler}.