OC-归档（序列化）(了解的不多 没细看)

IOS的本地存储：plist属性列表(Property List)，归档，sqlite，coredata

什么是归档

归档就是将对象打包成二进制序列

归档的作用

归档可以将程序中使用的多个对象及其属性值，以及他们的相互关系保存到文件中 或者发送给另一个进程
简单点说就是将对象以对象的形式存储在文件中 并且还可以以对象的形式从文件中拿出来

够可以将相互关联的多个对象归档为二进制文件，

NSCoding协议

归档需要先引入<NSCoding>协议

@protovol NSCoding
-(void)encodeWithCoder:(NSCoder*)aCoder;
-(id)initWithCoder:(NSCoder*)aDecoder;
@end

NSCoder 是一个抽象类 NSKeyedArchiver和NSKeyedUnarchiver是NSCoder的子类
NSCoder就相当于一个二进制空间
NSCoder的实例成为归档器

-(void)encodeWithCoder:(NSCoder*)aCode//指定对象归档规则

-(void)encodeWithCoder:(NSCoder*)aCode
{
    
	//如果父类适用于NSCoding协议 则super也需要调用 
	//[super encoderWithCoder:aCoder];
	[coder encodeObject:/*归档变量*/ forKey:/*归档名称*/];
	[coder encodeObject:self.name forKey:@"name"];
}

-(id)initWithCoder:(NSCoder*)aDecoder//指定对象解档规则

//如果父类适用NSCoding协议 则
//self = [super initWithCoder:aDecoder];
//如果父类不适用则调用
//self = [super init];
接收变量 = [coder decodeObjectForKey:/*归档名称*/];
self.name = [coder decodeObjectForKey:@"name"];

NSKeyedArchiver archiveRootObject:toFile: //对目标对象进行归档

[NSKeyedArchiver archiveRootObject:归档对象 toFile:归档目标路径]
[NSKeyedArchiver archiveRootObject:a toFile:@"/Users/RenkaiYang/Desktop/archive/test.txt"]

NSKeyedUnarchiver unarchiveObjectWithFile://通过解档目标文件初始化对象

A *a = [NSKeyedUnarchiver unarchiveObjectWithFile:目标文件路径];
A *a = [NSKeyedUnarchiver unarchiveObjectWithFile:@"/Users/RenkaiYang/Desktop/archive/test.txt"];

(id) initForWritingwithMutableData:(NSMutableData*)data

多对象的
将预先生成的NSMuable实例作为参数 初始化NSkeyedArchiver实例 这个data的数据会被保留 最后作为归档

NSMutableData *data = [NSMutableData data];//创建一个data对象
//根据二进制流创建NSKeyedArchiver对象
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];
//感觉可能是将在archiver和data之间创建一个二进制流

[archiver encodeObject:a forKey:@“a”];
[archiver encodeObject:aa forKey:@“aa”];

实例

dog.h

@interface Dog : NSObject<NSCoding>
@property (nonatomic,copy)NSString* name;
@end

dog.m

#import "dog.h"

@implementation Dog
-(void)encodeWithCoder:(NSCoder *)coder
{
    
    [coder encodeObject:self.name forKey:@"name"];
}
-(nullable instancetype)initWithCoder:(NSCoder *)coder
{
    
    if(self = [super init])
    {
    
        self.name = [coder decodeObjectForKey:@"name"];
    }
    return self;
}
@end

main.m

//
// main.m
// OCTest
//
// Created by Renkai Yang on 2022/7/26.
//

#import <Foundation/Foundation.h>
#import "dog.h"
@interface A:NSObject<NSCoding>
@property (nonatomic,copy)NSString *name;
@property (nonatomic,assign)int age;
@property (nonatomic,assign)double weight;
@property (nonatomic,strong)Dog*dog;
@end
@implementation A
-(void)encodeWithCoder:(NSCoder *)coder//设定归档规则
{
    
    [coder encodeObject:self.name forKey:@"name"];
    [coder encodeInt:self.age forKey:@"age"];
    [coder encodeDouble:self.weight forKey:@"weight"];
    [coder encodeObject:self.dog forKey:@"dog"];//如果要给自定义类归档解档 就需要在自定义类中制定归档解档规则
}
-(nullable instancetype)initWithCoder:(NSCoder *)coder//设定解挡规则
{
    
    if(self = [super init])//这里要初始化主要是用来给新对象初始化
    {
    
        self.name = [coder decodeObjectForKey:@"name"];
        self.age = [coder decodeIntForKey:@"age"];
        self.weight = [coder decodeDoubleForKey:@"weight"];
        self.dog = [coder decodeObjectForKey:@"dog"];
    }
    return self;
}
@end
void test()//进行归档操作
{
    
    A *a = [[A alloc]init];
    a.name = @"Yang";
    a.age = 23;
    a.weight = 58.0;
    a.dog = [[Dog alloc]init];
    a.dog.name = @"大黄";
    NSLog(@"归档开始");
    if([NSKeyedArchiver archiveRootObject:a toFile:@"/Users/RenkaiYang/Desktop/archive/test.txt"])//将a对象归档到指定文件中
    {
    
        NSLog(@"归档成功");
    }
    else
    {
    
        NSLog(@"归档失败");
    }
}
int main(int argc, const char * argv[]) {
    
    @autoreleasepool {
    
        test();
        A *a = [NSKeyedUnarchiver unarchiveObjectWithFile:@"/Users/RenkaiYang/Desktop/archive/test.txt"];//通过解档文件对a进行初始化
        NSLog(@"%@",a.name);
        NSLog(@"%d",a.age);
        NSLog(@"%f",a.weight);
        NSLog(@"%@",a.dog.name);
    }
    return 0;
}

多对象归档
dog.h

@interface Dog : NSObject<NSCoding>
@property (nonatomic,copy)NSString* name;
@end

dog.m

#import "dog.h"

@implementation Dog
-(void)encodeWithCoder:(NSCoder *)coder
{
    
    [coder encodeObject:self.name forKey:@"name"];
}
-(nullable instancetype)initWithCoder:(NSCoder *)coder
{
    
    if(self = [super init])
    {
    
        self.name = [coder decodeObjectForKey:@"name"];
    }
    return self;
}
@end

main.m

//
// main.m
// OCTest
//
// Created by Renkai Yang on 2022/7/26.
//

#import <Foundation/Foundation.h>
#import "dog.h"
@interface A:NSObject<NSCoding>
@property (nonatomic,copy)NSString *name;
@property (nonatomic,assign)int age;
@property (nonatomic,assign)double weight;
@property (nonatomic,strong)Dog*dog;
@end
@implementation A
-(void)encodeWithCoder:(NSCoder *)coder//设定归档规则
{
    
    [coder encodeObject:self.name forKey:@"name"];
    [coder encodeInt:self.age forKey:@"age"];
    [coder encodeDouble:self.weight forKey:@"weight"];
    [coder encodeObject:self.dog forKey:@"dog"];//如果要给自定义类归档解档 就需要在自定义类中制定归档解档规则
}
-(nullable instancetype)initWithCoder:(NSCoder *)coder//设定解挡规则
{
    
    if(self = [super init])//这里要初始化主要是用来给新对象初始化
    {
    
        self.name = [coder decodeObjectForKey:@"name"];
        self.age = [coder decodeIntForKey:@"age"];
        self.weight = [coder decodeDoubleForKey:@"weight"];
        self.dog = [coder decodeObjectForKey:@"dog"];
    }
    return self;
}
@end
void test()
{
    
    A *a = [[A alloc]init];
    a.name = @"a";
    a.age = 23;
    a.weight = 58.0;
    a.dog = [[Dog alloc]init];
    a.dog.name = @"大黄";
    
    A *aa = [[A alloc]init];
    aa.name = @"aa";
    aa.age = 22;
    aa.weight = 57.0;
    aa.dog = [[Dog alloc]init];
    aa.dog.name = @"大黄1";
    NSLog(@"多对象归档开始");
    NSMutableData *data = [NSMutableData data];
    //根据二进制流创建NSKeyedArchiver对象
    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data];
    //对对象进行归档
    [archiver encodeObject:a forKey:@"a"];
    [archiver encodeObject:aa forKey:@"aa"];
    //结束归档
    [archiver finishEncoding];
    //将二进制流写入文件
    if([data writeToFile:@"/Users/RenkaiYang/Desktop/archive/test.txt" atomically:YES])//将a对象归档到指定文件中
    {
    
        NSLog(@"归档成功");
    }
    else
    {
    
        NSLog(@"归档失败");
    }
    
    
    
// NSLog(@"归档开始");
      //这里是调用NSKeyedArchiver的对象方法archiveRootObject
// if([NSKeyedArchiver archiveRootObject:a toFile:@"/Users/RenkaiYang/Desktop/archive/test.txt"])//将a对象归档到指定文件中
// {
    
// NSLog(@"归档成功");
// }
// else
// {
    
// NSLog(@"归档失败");
// }
}
int main(int argc, const char * argv[]) {
    
    @autoreleasepool {
    
        test();
// //单对象解档
// A *a = [NSKeyedUnarchiver unarchiveObjectWithFile:@"/Users/RenkaiYang/Desktop/archive/test.txt"];//通过解档文件对a进行初始化
// NSLog(@"%@",a.name);
// NSLog(@"%d",a.age);
// NSLog(@"%f",a.weight);
// NSLog(@"%@",a.dog.name);
        //多对象解档
        NSData* data = [NSData dataWithContentsOfFile:@"/Users/RenkaiYang/Desktop/archive/test.txt"];
        
        
        NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc]initForReadingWithData:data];
        A *a1 = [unarchiver decodeObjectForKey:@"a"];
        A *a2 = [unarchiver decodeObjectForKey:@"aa"];
        NSLog(@"a1:%@",a1.name);
        NSLog(@"a1:%d",a1.age);
        NSLog(@"a1:%f",a1.weight);
        NSLog(@"a1:%@",a1.dog.name);
        
        NSLog(@"a2:%@",a2.name);
        NSLog(@"a2:%d",a2.age);
        NSLog(@"a2:%f",a2.weight);
        NSLog(@"a2:%@",a2.dog.name);
    }
    return 0;
}