POST raw json code ios

i'm new to ios developing and i want to ask how can i post a raw json code to the server.

For Example: i want to send this JSON raw data to http://example.com/user

{ "user": 
                {   "username": "jkaaannyaad11",
                    "password": "secret123456",
                    "gender": "male",
                    "first_name": "assd",
                    "last_name": "ffsasd",
                    "birth_date": "can be null",
                    "phone_number": "12343234",
                                                                  "have_car":"1",
                                                                  "same_gender" :"0",
                                                                  "uid": "this is id for facebook , can be null"
                },
            "home": {
                    "longitude": "31.380301",
                    "latitude": "30.054272",
                    "name": "city"
                    },
            "work": {
                    "longitude": "30.068237",
                    "latitude": "31.024275",
                    "name": "village"
                    },
            "email": {
                    "email_type": "work",
                    "email": "hello.me@me.com"
                    }
            }

so how can i do it ?

Dearest Regards,