IOS NSDictionary 、 NSData 相互转换

// dictonary 转 NSData
+(NSData *)returnDataWithDictionary:(NSDictionary*)dict
{
NSMutableData *data = [[NSMutableData alloc]init];
NSKeyedArchiver* archiver = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];
[archiver encodeObject:dict forKey:@"talkData"];
[archiver finishEncoding];
return data;
}

// NSData转dictonary
+(NSDictionary*)returnDictionaryWithDataPath:(NSData*)data
{
//  NSData* data = [[NSMutableData alloc]initWithContentsOfFile:path]; 拿路径文件
NSKeyedUnarchiver* unarchiver = [[NSKeyedUnarchiver alloc]initForReadingWithData:data];
NSDictionary* myDictionary = [unarchiver decodeObjectForKey:@"talkData"];
[unarchiver finishDecoding];
return myDictionary;
}