AFNetworking 如何POST一个JSON数据到服务器

       NSString *pathStr=@"http://www.baidu.com" ;

                                AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@""]];//这里要将url设置为空

                                httpClient.parameterEncoding = AFJSONParameterEncoding;

                                [httpClient setDefaultHeader:@"Accept" value:@"text/json"];

                               
                                NSMutableDictionary *params=[[NSMutableDictionary alloc] init];   // 要传递的json数据是一个字典

                                [params setObject:UserID forKey:@"userId"];

                                [params setObject:[self.contDic objectForKey:@"weiboId" ] forKey:@"operateId"];

                                [params setObject:@"8d0ce196d0eafa27780cc3a7217de71d92474021dc0a4fc593d4f9b9eda320ca" forKey:@"key"];

                                 // httpClient 的postPath就是上文中的pathStr，即你要访问的URL地址，这里是向服务器提交一个数据请求，

                                [httpClient postPath:pathStr parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject) {

                                    NSLog(@"data====%@",params);