// 获取对象所有属性：- (NSArray*)propertyKeys{    unsigned int outCount, i;    objc_property_t *properties = class_copyPropertyList([self class], &outCount);    NSMutableArray *keys = [[NSMutableArray alloc] initWithCapacity:outCount];    for (i = 0; i < outCount; i++) {        objc_property_t property = properties[i];        NSString *propertyName = [[NSString alloc] initWithCString:property_getName(property) encoding:NSUTF8StringEncoding];        [keys addObject:propertyName];    }    free(properties);    return keys;}