NSDictionary-Accessors:为NSDictionary键入安全访问器，最好与从JSON解析的字典一起使用

NSDictionary-Accessors 为NSDictionary键入安全访问器，最好与从JSON解析的字典一起使用。 前： id value = nil; value = [dictionary objectForKey:@"id"]; if ([value isKindOfClass:[NSNumber class]]) { model.identifier = [value unsignedLongLongValue]; } value = [dictionary objectForKey:@"title"]; if ([value isKindOfClass:[NSString class]]) { model.title = value; } value = [dictionary objectForKey:@"content"]; if ([val