归档 NSKeyedArchiver

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:

　　

 //
 //  Person.m
 //  UILesson18_archiver
 //
 //  Created by Ager on 15/11/5.
 //  Copyright © 2015年 Ager. All rights reserved.
 //

 #import "Person.h"

 @implementation Person

 //对属性做归档处理
 - (void)encodeWithCoder:(NSCoder *)aCoder{

     [aCoder encodeObject:self.name  forKey:@"name"];
     [aCoder encodeInteger: self.age forKey:@"age"];

 }

 //反归档处理
 - (instancetype)initWithCoder:(NSCoder *)aDecoder{

     if (self = [super init]) {
         self.name = [aDecoder decodeObjectForKey:@"name"];
         self.age = [aDecoder decodeIntegerForKey:@"age"];
     }
     return self;
 }

 @end

2.完成归档,实现本地存储:(NSKeyedArchiver)

　　代码:　　

 //归档
     NSMutableData *data = [NSMutableData data];
     NSKeyedArchiver *keyed = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];
     [keyed encodeObject:per forKey:@"per"];
     //结束归档
     [keyed finishEncoding];
     //归档结束,存数据
     NSString *cachesPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[];

     NSLog(@"%@",cachesPath);

     NSString *newPath = [cachesPath stringByAppendingPathComponent:@"person"];
     [data writeToFile:newPath atomically:YES];

3.完成反归档,获取复杂对象:(NSKeyedUnarchiver)

　　代码:

     //反归档
     NSData *data1 = [NSData dataWithContentsOfFile:newPath];
     NSKeyedUnarchiver *unKeyed = [[NSKeyedUnarchiver alloc]initForReadingWithData:data1];

     Person *per1 = [unKeyed decodeObjectForKey:@"per"];
     [unKeyed finishDecoding];
     NSLog(@"%@  %ld",per1.name,per1.age);