iOS 对象的归档

对象归档的定义：

对象归档就是将对象归档以文件的形式保存到磁盘中，使用的时候以该文件保存的路径读取文件中的内容

使用NSKeyedArichiver进行归档、NSKeyedUnarchiver进行接档，这种方式会在写入、读出数据之前对数据进行序列化、反序列化操作。

单对象归档，多个对象归档，自定义对象归档

常用的归档一般用在工具类中，对不可变的数据进行归档，可变的数据不进行归档，用起来更加方便

 //1.一个对象归档

    NSString *homeDictionary = NSHomeDirectory();//获取根目录

    NSString *homePath  = [homeDictionary stringByAppendingPathComponent:@"archiver.data"];//添加储存的文件名

    //归档 toFile:路径 archiveRootObject:id对象

    [NSKeyedArchiver archiveRootObject:@"对象" toFile:homePath];

    //接档

    id object = [NSKeyedUnarchiver unarchiveObjectWithFile:homePath];

    NSLog(@"%@",object);

    //2.将多个对象归档

    NSMutableData *data = [NSMutableData data];

    //归档

    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];

    int aInt = 100;

    NSString *aString = @"I is an Apple";

    NSDictionary *aDict = @{@"a":@"b",@"c":@"d"};

    [archiver encodeObject:@(aInt) forKey:@"aInt"];

    [archiver encodeObject:aString forKey:@"aString"];

    [archiver encodeObject:aDict forKey:@"aDict"];

    [archiver finishEncoding];

    NSString *dataHomePath = [NSHomeDirectory() stringByAppendingPathComponent:@"data.archiver"];

    [data writeToFile:dataHomePath atomically:YES];

    //接档

    NSMutableData *muData = [[NSMutableData alloc]initWithContentsOfFile:dataHomePath];

    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc]initForReadingWithData:muData];

    NSInteger  anInt = [[unarchiver decodeObjectForKey:@"aInt"] integerValue];

    NSString *anString = [unarchiver decodeObjectForKey:@"aString"];

    NSDictionary *anDict = [unarchiver decodeObjectForKey:@"aDict"];

    [unarchiver finishDecoding];

    NSLog(@"anInt=%@,anString=%@,anDict=%@",@(anInt),anString,anDict);

    //3.自定义对象归档实现copy协议

    #import <Foundation/Foundation.h>

    @interface ArchiveCopy : NSObject

    @property (copy,nonatomic) NSString *name;

    @property (copy,nonatomic) NSString *anAge;

    end

- (void)encodeWithCoder:(NSCoder *)aCoder{

    [aCoder encodeObject:@"name"];

    [aCoder encodeObject:@"anAge"];

}

- (id)initWithCoder:(NSCoder *)aDecoder {

    if (self = [super init]) {

        _name = [aDecoder decodeObjectForKey:@"name"];

        _anAge = [aDecoder decodeIntegerForKey:@"anAge"];

    }

    return self;

}

#pragma mark - NSCoping

- (id)copyWithZone:(NSZone *)zone {

    ArchiveCopy *copy = [[[self class] allocWithZone:zone] init];

    copy.name = [self.name copyWithZone:zone];

    copy.anAge = [self.address copyWithZone:zone];

    return copy;

}