NSUrlsession use POST

NSUrlSession POST

    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
    
    NSMutableURLRequest *request = [NSMutableURLRequest
                                    requestWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"http://%@:%@/getAllUser",[GlobalVar serverIp],[GlobalVar serverPort]]]];
    
    NSDictionary *requestData = [[NSDictionary alloc] initWithObjectsAndKeys:
                                 [defu objectForKey:@"ComId"], @"id",
                                 nil];
    NSError *error;
    NSData *postData = [NSJSONSerialization dataWithJSONObject:requestData options:0 error:&error];
    [request setValue:@"application/json; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
    [request setHTTPMethod:@"POST"];
    [request setHTTPBody:postData];
    //NSLog(@"%@",requestData);
    
    NSURLSession *session =  [NSURLSession sharedSession];
    
    NSURLSessionDataTask* dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        if (!error) {
            dispatch_async(dispatch_get_main_queue(), ^{
                NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:data options:0 error:NULL];
                NSLog(@"%@",dic);
                RetArray = [[NSArray alloc] init];
                RetArray = [dic objectForKey:@"res"];
                [defu setObject:RetArray forKey:@"userList"];
                [defu synchronize];
                
                [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
                [[NSNotificationCenter defaultCenter]postNotificationName:@"gotoloadTable" object:self];
            });
        }
    }];
    [dataTask resume];