把自定义的类对象编码到NSData中

NSData *data = http://www.mamicode.com/[NSKeyedArchiver archivedDataWithRootObject:bc];//归档,bc是一个自定义的类对象,归档的类型是二进制

NSArray *array = [NSKeyedUnarchiver unarchiveObjectWithData:udObject];//解档

NSKeyedUnarchiver归档