How to GET json data from server in an efficient and faster way.?

Hey folks, I've the following code to get data from server but it takes too long to load and show in tableView. I need it to be done in faster way.
I have my NSURLRequest in viewDidLoad.

- (void)viewDidLoad {
    
    NSNumber *getID=connectorClass.IdBeingPassed;
    NSString *getname=connectorClass.movieNameBeingPassed;
    
  
    
    NSNumber *getVote=connectorClass.voteBeingPassed;
    NSString *myNumberInString = [getVote stringValue];
    NSString *movieIDinString= [getID stringValue];
       _labelText.text=getname;
    //------castApi----//
    
    
   
    [super viewDidLoad];
    [[self tableView2]setDelegate:self ];
    [[self tableView2]setDataSource:self];
    array=[[NSMutableArray alloc]init];
    
    NSString *castString = [NSString stringWithFormat:@"https://api.themoviedb.org/3/movie/%@/credits?api_key=c4bd81709e87b1208609433c49",movieIDinString];
    NSURL *url=[NSURL URLWithString:castString];

    NSURLRequest *request=[NSURLRequest requestWithURL:url];
    connection=[NSURLConnection connectionWithRequest:request delegate:self];
    if (connection)
    {
        webData=  [[NSMutableData alloc]init];
    }
    
}

- (void)viewDidLoad {
    
    NSNumber *getID=connectorClass.IdBeingPassed;
    NSString *getname=connectorClass.movieNameBeingPassed;
    
  
    
    NSNumber *getVote=connectorClass.voteBeingPassed;
    NSString *myNumberInString = [getVote stringValue];
    NSString *movieIDinString= [getID stringValue];
       _labelText.text=getname;
    //------castApi----//
    
    
   
    [super viewDidLoad];
    [[self tableView2]setDelegate:self ];
    [[self tableView2]setDataSource:self];
    array=[[NSMutableArray alloc]init];
    
    NSString *castString = [NSString stringWithFormat:@"https://api.themoviedb.org/3/movie/%@/credits?api_key=c4bd81709e87b1208609433c49",movieIDinString];
    NSURL *url=[NSURL URLWithString:castString];

    NSURLRequest *request=[NSURLRequest requestWithURL:url];
    connection=[NSURLConnection connectionWithRequest:request delegate:self];
    if (connection)
    {
        webData=  [[NSMutableData alloc]init];
    }
    
}