Category 添加属性

1. @property (nonatomic, copy) NSString *name;

- (void)setName:(NSString *)name {
    
    objc_setAssociatedObject(self, @selector(name), name, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    
}

- (NSString *)name {
    
   return objc_getAssociatedObject(self, @selector(name));
}