ios nsdata怎麽轉換son

NSData轉Json：先將NSData轉成字典，再將字典轉成Json

例如：

1、NSData轉字典

NSData *data = [[NSMutableData alloc] initWithContentsOfFile:[self dataFilePath]];

NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];

NSDictionary *myDictionary = [[unarchiver decodeObjectForKey:@"Some Key Value"]];

[unarchiver finishDecoding];

2、字典轉Json

NSString *jsonStr=[myDictionary JSONRepresentation];