How can I catch NULL exceptions in iOS from json -

my app pretty complete , in testing phase. noticed in our database, there numerous json data return null, not majority. first name data null , last name have data, or vice versa. app crashes when receives instance null.

how can catch null , make exception (for different fields of json data)?

there few possible solutions.

1) testing nsnull

if want test null (i'm assuming nsnull) following works: how can check if got null json?

2) replacing nsnulls strings

if you're using dictionary , want replace nulls empty strings you're looking for: replace nsnull objects in nsdictionary

3) nsdictionary category

i use category adds new method nsdictionary. returns nil if value nsnull (originally touchjson, dealing nsnull)

nsdictionary+utility.h

#import <foundation/foundation.h>  @interface nsdictionary (utility)  - (id)objectforkeynotnull:(id)key;  @end 

nsdictionary+utility.m

#import "nsdictionary+utility.h"  @implementation nsdictionary (utility)  - (id)objectforkeynotnull:(id)key {     id object = [self objectforkey:key];     if (object == [nsnull null]){         return nil;     }      return object; }  @end 

implementation class (.m)

#import "nsdictionary+utility.h"  ...  id success = [json objectforkeynotnull:@"success"]; if (success == nil){     /* "success" either nsnull or didn't exist in json. */ }