iOS AFNetworking urlencoded

只需要加上：

[manager.requestSerializer setValue:@" application/x-www-form-urlencoded; charset=UTF-8" forHTTPHeaderField:@"Content-Type];

示例：

NSString *url = [NSString stringWithFormat:@"%@%@",APIBASE,APIUSERENDPOINT];

NSDictionary* parametersDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
                          username, @"username",
                          password, @"password",
                          nil
                          ];

AFHTTPSessionManager *manager = [[AFHTTPSessionManager alloc]initWithSessionConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
    [manager.requestSerializer setValue:@"application/x-www-form-urlencoded; charset=UTF-8" forHTTPHeaderField:@"Content-Type"];
    manager.requestSerializer = [AFHTTPRequestSerializer serializer];

[manager POST:url parameters:parametersDictionary progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
    NSLog(@"%@",responseObject);
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
    NSLog(@"%@",error);
}];