How can I see the contents of the HTTP request

Help you next big cow
Now doing client-side interactivity needs and service parts. ,
The service side of said received request is empty. But I obviously have the following phrase, json string is also content.

request setHTTPBody: [json dataUsingEncoding: NSUTF8StringEncoding]];

Now want to print out the contents of HTTP, look I filled content. How we can now print out the contents of the HTTP request it?
Reply:
Ethereal, using a PC to do wifi ap, the PC connected to the network via lan, mobile phones even this ap, and then use software like wireshark capture
Reply:
Would that be possible to use objectiveC method implementation?