iOS 對象的歸檔

對象歸檔的定義：

對象歸檔就是將對象歸檔以文件的形式保存到磁盤中，使用的時候以該文件保存的路徑讀取文件中的內容

使用NSKeyedArichiver進行歸檔、NSKeyedUnarchiver進行接檔，這種方式會在寫入、讀出數據之前對數據進行序列化、反序列化操作。

單對象歸檔，多個對象歸檔，自定義對象歸檔

常用的歸檔一般用在工具類中，對不可變的數據進行歸檔，可變的數據不進行歸檔，用起來更加方便

 //1.一個對象歸檔

    NSString *homeDictionary = NSHomeDirectory();//獲取根目錄

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

    //歸檔 toFile:路徑 archiveRootObject:id對象

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

    //接檔

    id object = [NSKeyedUnarchiver unarchiveObjectWithFile:homePath];

    NSLog(@"%@",object);

    //2.將多個對象歸檔

    NSMutableData *data = [NSMutableData data];

    //歸檔

    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];

    //接檔

    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.自定義對象歸檔實現copy協議

    #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;

}