對象的類以及每個成員對象都要實現(xiàn)NSCoding協(xié)議
第一種.多個對象歸檔成一個文件
1.歸檔（編碼歸檔）

@interface NSString (filePath)
-(NSString *)documentsFilePath;
@end
@implementation NSString (filePath)
-(NSString *)documentsFilePath
{
    NSString * documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)firstObject];
    NSString * filePath = [documentsPath stringByAppendingString:self];
    return filePath;
}
@end

#define kFirstDataPath @“/first.archive"
#define kSecondDataPath @"/second.archive"
#define ARCHIVE_KEY @"dataArray"

self.plistFilePath = [kFirstDataPath documentsFilePath];
//初始化文件
- (void)createArchiveFileIfNeeded {

    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL dbexits = [fileManager fileExistsAtPath:self.plistFilePath];

    if (!dbexits) {
        //添加一些測試數(shù)據(jù)
        NSDateFormatter *aDataFormatter = [[NSDateFormatter alloc] init];
        [aDataFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
        NSDate *date1 = [aDataFormatter dateFromString:@"2016-10-01 16:01:03"];
        Note *note1 = [[Note alloc] initWithDate:date1 content:@"welcome to 317hu"];

        NSMutableArray *array = [[NSMutableArray alloc] init];
        [array addObject:note1];

        //1.構造archiver對象
        NSMutableData *theData = [NSMutableData data];
        NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:theData];
        //2.用指定key歸檔多個對象
        [archiver encodeObject:array forKey:ARCHIVE_KEY];
        [archiver encodeObject:@"tony" forKey:@"name"];
       //2.1結束歸檔編碼
        [archiver finishEncoding]; //No more values can be encoded after this method is called. You must call this method when finished.
        //3.將歸檔好的data,保存到一個沙盒文件(也可以將新建，修改，刪除后的數(shù)據(jù)寫入到文件)
        [theData writeToFile:self.plistFilePath atomically:TRUE];
    }
}

//4.對象成員要實現(xiàn)NSCoding
//  Note.h
#import <Foundation/Foundation.h>
@interface Note : NSObject <NSCoding>

@property(nonatomic, strong) NSDate *date;
@property(nonatomic, strong) NSString *content;
- (instancetype)initWithDate:(NSDate *)date content:(NSString *)content;
- (instancetype)init;
@end
//  Note.m
#import "Note.h"

@implementation Note

- (instancetype)initWithDate:(NSDate *)date content:(NSString *)content {
    self = [super init];
    if (self) {
        _date = date;
        _content = content;
    }
    return self;
}

- (instancetype)init {
    self = [super init];
    if (self) {
        _date = [[NSDate alloc] init];
        _content = @"";
    }
    return self;
}

#pragma mark--實現(xiàn)NSCoding協(xié)議
- (void)encodeWithCoder:(NSCoder *)aCoder {
    [aCoder encodeObject:_date forKey:@"date"];
    [aCoder encodeObject:_content forKey:@"content"];
}

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
    _date = [aDecoder decodeObjectForKey:@"date"];
    _content = [aDecoder decodeObjectForKey:@"content"];
    return self;
}

@end

2.反歸檔（解碼使用）

//獲取數(shù)據(jù)
- (NSMutableArray *)getDataArray {

    NSData *theData = [NSData dataWithContentsOfFile:self.plistFilePath];

    if ([theData length] > 0) {
        //5.構建unArchiver對象
        NSKeyedUnarchiver *unArchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:theData];
        NSMutableArray *listData = [unArchiver decodeObjectForKey:ARCHIVE_KEY];
        //5.1 解碼完成
        [unArchiver finishDecoding];//Invoking this method allows the receiver to notify its delegate and to perform any final operations on the archive. Once this method is invoked, the receiver cannot decode any further values.

        return listData;
    }
    return nil;
}

第二種：一個對象歸檔成一個文件（對象和對象成員也要支持 NSCoding）
不需要[archiver finishEncoding]和[unArchiver finishDecoding]，因為只有一個對象

#pragma mark - ArchiverAndUnArchiver
//歸檔
-(void)archiveMethod
{
    NSMutableArray *array = [[NSMutableArray alloc] init];
    [array addObject:note1];
    //1.歸檔對應到一個文件
    [NSKeyedArchiver archiveRootObject:array toFile:[kSecondDataPath documentsFilePath]];
}
//解檔
-(void)unarchiverMethod
{
    //2.獲得反歸檔的對象
    NSArray * array = [NSKeyedUnarchiver unarchiveObjectWithFile:[kSecondDataPath documentsFilePath]];
    //使用
    self.data = array;
}

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