Convert a JSON NSData to NSDictionary

问题:

I'm using an API service of a web service and it is written in their description that they send JSON data wich also matches in my opinion with the response I get from it. Here a part of it which I got from the NSURLConnection-Delegate (connection didReceiveData: (NSData *) data) and converted in a NSString using:

NSLog(@"response: %@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]); 

Here the snippet:

{"scans":  {     "Engine1“:      {         "detected": false,          "version": "1.3.0.4959",          "result": null,          "update": "20140521"     },      "Engine2“:      {         "detected": false,          "version": "12.0.250.0",          "result": null,          "update": "20140521"     },          ...     },     "Engine13":      {          "detected": false,          "version": "9.178.12155",          "result":  

In the NSLog-String it stops there. Now I would like to know from you whats wrong that I can't convert this data to a JSON Dictionary with this lines of code:

NSError* error;     NSMutableDictionary *dJSON = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:&error]; 

I experiment with some options but always the same error:

Error Domain=NSCocoaErrorDomain Code=3840 "The operation couldn’t be completed. (Cocoa error 3840.)"  (Unexpected end of file while parsing object.) UserInfo=0x109260850 {NSDebugDescription=Unexpected end of file while parsing object.} 

Everything indicates that the JSON packet is incomplete but I don't know how to check it or how to look for the issue which should be located in my code.

回答1:

Did you implemented all the delegate methods of NSURLConnectionDelagate.It looks like you are taking the data for conversion from "- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data" delagate method. If so you may get incomplete data and that can not be converted.

Try this:

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {     // A response has been received, this is where we initialize the instance var you created     // so that we can append data to it in the didReceiveData method     // Furthermore, this method is called each time there is a redirect so reinitializing it     // also serves to clear it     lookServerResponseData = [[NSMutableData alloc] init]; }  - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {     // Append the new data to the instance variable you declared     [lookServerResponseData appendData:data]; }   - (void)connectionDidFinishLoading:(NSURLConnection *)connection {     // The request is complete and data has been received     // You can parse the stuff in your instance variable now     NSError *errorJson=nil;     NSDictionary* responseDict = [NSJSONSerialization JSONObjectWithData:lookServerResponseData options:kNilOptions error:&errorJson];       NSLog(@"responseDict=%@",responseDict);      [lookServerResponseData release];     lookServerResponseData = nil; } 

Here, lookServerResponseData is instance of NSMutableData declared globally.

Hope it will help.

文章来源: Convert a JSON NSData to NSDictionary