code: public String allRequestParamsAsUrl(Collection<String> excludes) {
  
          StringBuffer result = new StringBuffer(512);
          Map<?, ?> params = getJsp().getRequest().getParameterMap();
          Iterator<?> i = params.entrySet().iterator();
          while (i.hasNext()) {
              Entry<?, ?> entry = (Entry<?, ?>)i.next();
              String param = (String)entry.getKey();
              if ((excludes == null) || (!excludes.contains(param))) {
                  if (result.length() > 0) {
                      result.append("&");
                  }
                  result.append(param);
                  result.append("=");
                  String value;
                  if (entry.getValue() instanceof String[]) {
                      value = ((String[])entry.getValue())[0];
                  } else {
                      value = (String)entry.getValue();
                  }
                  String encoded = CmsEncoder.encode(value, getCms().getRequestContext().getEncoding());
                  result.append(encoded);
              }
          }
          return result.toString();
      }
docs: Returns all initialized parameters of the current request
  that are not in the given exclusion list as hidden field tags that can be inserted in a form.<p>
  
  @param excludes the parameters to exclude
  
  @return all initialized parameters of the current request