阅读以下代码 /* * copyright 2016 google inc. all rights reserved. * * licensed under the apache license, version 2.0 (the "license"); * you may not use this file except in compliance with the license. * you may obtain a copy of the license at * * http://www.apache.org/licenses/license-2.0 * * unless required by applicable law or agreed to in writing, software * distributed under the license is distributed on an "as is" basis, * without warranties or conditions of any kind, either expres