個人對於歸檔的初級理解

- (void)viewDidLoad {
    [super viewDidLoad];
    
    NSString *str = @"abc";
    [NSKeyedArchiver archiveRootObject:str toFile:@"/Users/apple/Desktop/test.plist"];
    
    NSString *str1 = [NSKeyedUnarchiver unarchiveObjectWithFile:@"/Users/apple/Desktop/test.plist"];
    NSLog(@"%@", str1);
    
    Student *stu = [[Student alloc] init];
    stu.name = @"Zhangsan";
    stu.age = 30;
    [NSKeyedArchiver archiveRootObject:stu toFile:@"/Users/apple/Desktop/student.plist"];
    
    Student *stu1 = [NSKeyedUnarchiver unarchiveObjectWithFile:@"/Users/apple/Desktop/student.plist"];
    NSLog(@"%p, %p", stu, stu1);
    NSLog(@"%@:%d, %@:%d", stu.name, stu.age, stu1.name, stu1.age);
    
    NSData *stuData = [NSKeyedArchiver archivedDataWithRootObject:stu];
    [stuData writeToFile:@"/Users/apple/Desktop/stu.plist" atomically:YES];
    
    NSData *stuData2 = [NSData dataWithContentsOfFile:@"/Users/apple/Desktop/stu.plist"];
    Student *stu3 = [NSKeyedUnarchiver unarchiveObjectWithData:stuData2];
    NSLog(@"%@:%d---%@:%d", stu.name, stu.age, stu3.name, stu3.age);
    
    NSUserDefaults *userDefault = [NSUserDefaults standardUserDefaults];
    [userDefault setObject:stuData forKey:@"xxxx"];
    NSData *stuData3 = [userDefault objectForKey:@"xxxx"];
    Student *stu4 = [NSKeyedUnarchiver unarchiveObjectWithData:stuData3];
    NSLog(@"%@:%d", stu4.name, stu4.age);
    
    stu4.dog = [[Dog alloc] init];
    stu4.dog.name = @"小強";
    [NSKeyedArchiver archiveRootObject:stu4 toFile:@"/Users/apple/Desktop/dog.plist"];
}

 要記住一點的就是，當對自定義的類使用歸檔的話，必須除了先協議委託<NScoding>這個協議之外，同時在.m中實現NScoding中的兩個required方法

- (void)encodeWithCoder:(NSCoder *)aCoder
{
    [aCoder encodeObject:_name forKey:kNameKey];
    [aCoder encodeInteger:_age forKey:kAgeKey];
    [aCoder encodeObject:_dog forKey:kDogKey];
}

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super init];
    if (self) {
        self.name = [aDecoder decodeObjectForKey:kNameKey];
        self.age = [aDecoder decodeIntegerForKey:kAgeKey];
        self.dog = [aDecoder decodeObjectForKey:kDogKey];
    }
    
    return self;
}