对象的归档/解挡

// 告诉系统需要归档哪些属性'怎么去存,存那些'
- (void)encodeWithCoder:(NSCoder*)coder
{
[coder encodeObject:_name forKey:@"name"];
[coder encodeInteger:_age forKey:@"age"];
}

// 告诉系统需要解档哪些属性'怎么取,取那些'
- (instancetype)initWithCoder:(NSCoder*)coder
{
self = [super init];
if (self) {
_name = [coder decodeObjectForKey:@"name"];
_age = [coder decodeIntegerForKey:@"age"];
}
return self;
}