很多时候我们都需要将对象序列化，比如将一个对象存入到NSUserDefault 里面去的时候，由于NSUserDefault支持存入的类型有限制，所以很多时候我们需要将NSObject类型的对象转换成NSData再存入进去。

- (id)initWithCoder:(NSCoder *)aDecoder
{self = [super init];if (self) {self.country = [aDecoder decodeObjectForKey:@"country"];self.city = [aDecoder decodeObjectForKey:@"city"];self.region = [aDecoder decodeObjectForKey:@"region"];self.street = [aDecoder decodeObjectForKey:@"street"];self.location = [aDecoder decodeObjectForKey:@"location"];}return self;
}- (void)encodeWithCoder:(NSCoder *)aCoder
{[aCoder encodeObject:_country forKey:@"country"];[aCoder encodeObject:_city forKey:@"city"];[aCoder encodeObject:_region forKey:@"region"];[aCoder encodeObject:_street forKey:@"street"];[aCoder encodeObject:_location forKey:@"location"];
}

当你要进行对象拷贝的时候需要遵循NSCopy协议

- (id)copyWithZone:(NSZone *)zone {id copy = [[[self class] alloc] init];if (copy) {[copy setId:[self.id copyWithZone:zone]];[copy setNickName:[self.nickName copyWithZone:zone]];}return copy;
}