Archiver是持久化數據的一種方式，他跟 Plist的區別在於他能持久化自定義對象。但他沒Plist那麼方便。

Archiver默認能持久化的數據有NSNumber,NSArray,NSDictionary,NSString,NSData,因為這幾個對象已經實現了

協議。假設我們要實現一個對象的Archiver持久化 ，也必須實現該對象。

1.協議主要為歸檔/恢復文件兩個方法

//恢復歸檔文件為對象
-(id)initWithCoder:(NSCoder *)aDecoder
//歸檔，使對象持久化
-(void)encodeWithCoder:(NSCoder *)aCoder

如下 ，我們首先獲取歸檔文件的路徑

#pragma mark 獲取文件路徑
- (NSString *) filePath
{
    NSArray *dirPaths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSAllDomainsMask, YES);
    NSString *dirPath=dirPaths[0];
    NSString *filePath=[dirPath stringByAppendingPathComponent:@"aa.archiver"];
    return filePath;
}

2.系統默認對象如何歸檔（NSNumber,NSArray,NSDictionary,NSString,NSData）

#pragma mark 歸檔/恢復 Array對象
- (void) savearray
{
    
    NSString *filePath=[self filePath];
//
//    NSArray *arr=@[@"ttt",@"BBB",@25];
//    [NSKeyedArchiver archiveRootObject:arr toFile:filePath];
//
    NSArray *arr1=[NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
    NSLog(@"%@",arr1);
}

#pragma mark 歸檔/恢復 Dictionary對象
- (void) saveDic
{
    NSString *filePath=[self filePath];
//    NSDictionary *dict=@{@"name":@"lean",@"age":@25};
//    BOOL flag=[NSKeyedArchiver archiveRootObject:dict toFile:filePath];
//    NSLog(@"%d",flag);
    NSDictionary *dict2=[NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
    NSLog(@"%@",dict2);
}

#import 

@interface Person : NSObject 

@property (nonatomic,copy) NSString *name;
@property (nonatomic,assign) int age;

+ (Person *) initWithName:(NSString *)name andAge:(int) age;

@end

#import "Person.h"

@implementation Person

+ (Person *) initWithName:(NSString *)name andAge:(int) age
{
    Person *p=[[Person alloc] init];
    p.name=name;
    p.age=age;
    return p;
}

-(void)encodeWithCoder:(NSCoder *)aCoder
{
    [aCoder encodeObject:self.name forKey:@"name"];
    [aCoder encodeInt:self.age forKey:@"age"];
}

-(id)initWithCoder:(NSCoder *)aDecoder
{
    [self setName:[aDecoder decodeObjectForKey:@"name"]];
    [self setAge:[aDecoder decodeIntForKey:@"age"]];
    return self;
}

@end

encodeInt:forkey: encodeDouble:forkey: encodeFloat:forkey:

decodeObjectForKey: decodeIntForKey: decodeDoubleForKey:

NSKeyedArchiver archiveRootObject:toFile:

NSKeyedUnarchiver unarchiveObjectWithFile:

分別是對需要歸檔。恢復的對象進行操作的兩個類

定義完了Person類後，在需要歸檔的地方調用如下：

#pragma mark 歸檔/恢復 自定義對象
- (void) savePerson
{
    NSString *filePath=[self filePath];
    Person *p=[Person initWithName:@"lean" andAge:22];
    BOOL flag=[NSKeyedArchiver archiveRootObject:p toFile:filePath];
    Person *p2=[NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
    NSLog(@"%d-%d",flag,p2.age);
}

#import "Person.h"

@interface Student : Person

@property (nonatomic ,assign) int no;

+ (Student *) initWithName:(NSString *)name andAge:(int) age andNO:(int) no;

@end

-(id)initWithCoder:(NSCoder *)aDecoder
{
    if (self=[super initWithCoder:aDecoder]) {
        [self setNo:[aDecoder decodeIntForKey:@"no"]];
    }
    return self;
}

-(void)encodeWithCoder:(NSCoder *)aCoder
{
    [super encodeWithCoder:aCoder];
    [aCoder encodeInt:self.no forKey:@"no"];
}

#pragma mark 歸檔/恢復 自定義子類對象
- (void) saveStudent
{
    NSString *filePath=[self filePath];
    Student *p=[Student initWithName:@"lean" andAge:22 andNO:150133];
    BOOL flag=[NSKeyedArchiver archiveRootObject:p toFile:filePath];
    Student *p2=[NSKeyedUnarchiver unarchiveObjectWithFile:filePath];
    NSLog(@"%d-%@",flag,p2.name);
}