api-servlet/src/main/java/org/ocpsoft/rewrite/servlet/util/QueryStringBuilder.java
public QueryStringBuilder addParameterLists(final Map<String, List<String>> params)
   {
      if (params != null)
      {
         for (Entry<String, List<String>> entry : params.entrySet())
         {
            List<String> values = null;
            if (entry.getValue() != null)
            {
               values = new ArrayList<String>(entry.getValue());
            }
            parameters.put(entry.getKey(), values);
         }
      }
      return this;
   }
public QueryStringBuilder addParameterLists(final Map<String, List<String>> params)
   {
      if (params != null)
      {
         for (Entry<String, List<String>> entry : params.entrySet())
         {
            List<String> values = null;
            if (entry.getValue() != null)
            {
               values = new ArrayList<String>(entry.getValue());
            }
            parameters.put(entry.getKey(), values);
         }
      }
      return this;
   }
Add parameters from the given map of name=value pairs. For parameters with more than one value, each value will be
appended using the same name. If a parameter already exists, append new values to the existing list of values for
that parameter.