dispatch_group_t group=dispatch_group_create();
dispatch_queue_t queue = dispatch_queue_create("com.livotal.httprequest",DISPATCH_QUEUE_CONCURRENT);
dispatch_group_enter(group);
[LFLHttpClient refreshTokenToNewsuccess:^(id _Nonnull responseSuc) {
dispatch_group_leave(group);//方法A结束回调之后，开始方法B
}];
\
dispatch_group_notify(group, queue, ^{
//方法B
});
