从谷歌云端点使用生成的Objective-C客户端在GTLService.h中包含一个字段APIKey
// Some services require a developer key for quotas and limits. Setting this
// will include it on all request sent to this service via a GTLQuery class.
@property (nonatomic, copy) NSString *APIKey;
如何访问服务器代码中传递的值(Java加上Endpoint批注)?