复杂对象无法象 NSString,NSArray等简单对象一样直接通过 writeToFile 实现持久化,当对复杂对象进行持久化时需要将其转化为 NSData (归档),但获取数据时,将 NSData 转化为复杂对象 (反归档)

下面通过一个简单的 Person 类实现归档和反归档:

1.新建 Peoson 类,有两个属性 name,age,其需要遵守 <NSCoding> 协议,实现- (void)encodeWithCoder: 和 - (instancetype)initWithCoder: 方法

　　代码:

 1 //
 2 //  Person.m
 3 //  UILesson18_archiver
 4 //
 5 //  Created by Ager on 15/11/5.
 6 //  Copyright © 2015年 Ager. All rights reserved.
 7 //
 8 
 9 #import "Person.h"
10 
11 @implementation Person
12 
13 //对属性做归档处理
14 - (void)encodeWithCoder:(NSCoder *)aCoder{
15     
16     [aCoder encodeObject:self.name  forKey:@"name"];
17     [aCoder encodeInteger: self.age forKey:@"age"];
18     
19 }
20 
21 //反归档处理
22 - (instancetype)initWithCoder:(NSCoder *)aDecoder{
23     
24     if (self = [super init]) {
25         self.name = [aDecoder decodeObjectForKey:@"name"];
26         self.age = [aDecoder decodeIntegerForKey:@"age"];
27     }
28     return self;
29 }
30 
31 @end

2.完成归档,实现本地存储:(NSKeyedArchiver)

　　代码:　　

 1 //归档
 2     NSMutableData *data = [NSMutableData data];
 3     NSKeyedArchiver *keyed = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];
 4     [keyed encodeObject:per forKey:@"per"];
 5     //结束归档
 6     [keyed finishEncoding];
 7     //归档结束,存数据
 8     NSString *cachesPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
 9     
10     NSLog(@"%@",cachesPath);
11     
12     NSString *newPath = [cachesPath stringByAppendingPathComponent:@"person"];
13     [data writeToFile:newPath atomically:YES];

3.完成反归档,获取复杂对象:(NSKeyedUnarchiver)

　　代码:

1     //反归档
2     NSData *data1 = [NSData dataWithContentsOfFile:newPath];
3     NSKeyedUnarchiver *unKeyed = [[NSKeyedUnarchiver alloc]initForReadingWithData:data1];
4     
5     Person *per1 = [unKeyed decodeObjectForKey:@"per"];
6     [unKeyed finishDecoding];
7     NSLog(@"%@  %ld",per1.name,per1.age);