oc调用rest api

- (IBAction)callapi:(id)sender {

NSURL *url=[NSURL URLWithString:@"http://..."];

NSURLRequest *request=[NSURLRequest requestWithURL:url];

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {

//json

NSDictionary *r=[NSJSONSerialization JSONObjectWithData:data options:0 error:NULL];

int cnt=[r count];

NSLog(@"%d",cnt);

[self resultlbl].text=[NSString stringWithFormat:@"%d",cnt];

//string

//NSString *str=[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

//NSLog(str);

//[self resultlbl].text=r[0][0];

}];

}

- (IBAction)postsend:(id)sender {

NSURL *url = [NSURL URLWithString:@"http://...."];

NSMutableURLRequest *rq = [NSMutableURLRequest requestWithURL:url];

[rq setHTTPMethod:@"POST"];

NSData *jsonData = [@"{ \"参数名\": 数值,\"参数名\":\"字符\"...}" dataUsingEncoding:NSUTF8StringEncoding];

[rq setHTTPBody:jsonData];

[rq setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];

[rq setValue:[NSString stringWithFormat:@"%ld", (long)[jsonData length]] forHTTPHeaderField:@"Content-Length"];

[NSURLConnection sendAsynchronousRequest:rq queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {

    //code

    NSString *str=[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

    NSLog(str);   

}];

}