Method to solve the problem of data loading failure due to null by JSON data

1. First analyze the problem:

Use NSJSONSerialization or AFN framework's AFHTTPSessionManager (the underlying layer is also NSJSONSerialization) to convert NSData data into OC objects. Sometimes the URL will appear correctly, and if the data is loaded, an error will be reported:

 reason: '-[NSNull length]: unrecognized selector sent to instance

Analysis of the reasons revealed that the converted OC object contains null. Therefore, NSNull does not have a length method, so an error will be reported.

2. Solution: Replace "null" with " .

1. First convert NSData data into NSString;

2. Then replace the converted NSString;

3. Replace the NSSting and convert it into NSData;

Convert to OC object

Here is a packaged method, and you can use it directly in the future

//Replace empty string in data+ (NSArray*)arrayWithNoNullArray:(NSArray*)originalArray {
  //array -> string
  NSData *data = [NSJSONSerialization dataWithJSONObject:originalArray options:0 error:nil];
  NSString *str =[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
  //replace  NSString *nStr = [str stringByReplacingOccurrencesOfString:@"null" withString:@"\"\""];
  //string -> array
  NSData *nData =[nStr dataUsingEncoding:NSUTF8StringEncoding];
  return [NSJSONSerialization JSONObjectWithData:nData options:0 error:nil];
}

Pass in an OC array containing null and directly return the replaced new array. There will be no problem if you use an array without null to load the data.

OK, the above is the solution to the failure of data loading due to null in JSON data. I hope it will be helpful to friends in need. If you have any questions, you can leave a message to communicate.