iOS NSCoding 与 NSSecureCoding

NSCoding

• 简介
  NSCoding是把数据存储在iOS和Mac OS上的一种极其简单和方便的方式，它把模型对象直接转变成一个文件，然后再把这个文件重新加载到内存里，并不需要任何文件解析和序列化的逻辑。
• 使用
  对象需要实现了NSCoding协议

// 存储
Teacher *t = [[Teacher alloc] init];
t.name = [NSMutableString stringWithString: @"李刚"];
t.age = 40;
t.className = @"English";

[NSKeyedArchiver archiveRootObject:t toFile:_file];

// 读取
Teacher *t = [NSKeyedUnarchiver unarchiveObjectWithFile:_file];

• 实现NSCoding协议
  需要实现两个方法
  - (void)encodeWithCoder:(NSCoder *)aCoder;
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder;

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
    self = [super init];
    if (self) {
        self.name = [aDecoder decodeObjectOfClass:[NSMutableString class] forKey:NSStringFromSelector(@selector(name))];
        self.age = [[aDecoder decodeObjectOfClass:[NSNumber class] forKey:NSStringFromSelector(@selector(age))] unsignedIntegerValue];
        self.className = [aDecoder decodeObjectOfClass:[NSString class] forKey:NSStringFromSelector(@selector(className))];
    }
    return self;
}

- (void)encodeWithCoder:(NSCoder *)aCoder {
    [aCoder encodeObject:self.name forKey:NSStringFromSelector(@selector(name))];
    [aCoder encodeObject:[NSNumber numberWithUnsignedInteger:self.age] forKey:NSStringFromSelector(@selector(age))];
    [aCoder encodeObject:self.className forKey:NSStringFromSelector(@selector(className))];
}

NSSecureCoding

• 简介
  NSSecureCoding是NSCoding的变种，因为NSCoding毕竟不太安全，大部分支持NSCoding的系统对象都已经升级到支持NSSecureCoding了，如AFNetworking的AFURLSessionManager。

未完待续