归档/解档

一、对系统类进行归档/解档

第一种：对集合类对象进行归档/解档

归档:

 NSArray *arr = @[@"one", @1, @"two", @{@"one":@"hello"}, @[@1, @2]];
        BOOL ret = [NSKeyedArchiver archiveRootObject:arr toFile:@"文件路径/arr.archive"];
        if (ret) {
            NSLog(@"归档成功");
        }else{
            NSLog(@"归档失败");
        }

解档

方法（1）

NSArray *arr1 = [NSKeyedUnarchiver unarchiveObjectWithFile:@"文件路径/arr.archive"];
        NSLog(@"%@", arr1);

方法（2）

  NSData *data = [[NSData alloc] initWithContentsOfFile:@"文件路径/arr.archive"];
        NSArray *arr2 = [NSKeyedUnarchiver unarchiveObjectWithData:data];
        NSLog(@"%@", arr2);

第二种:非集合类进行归档/解档

    NSString *name = @"hello";
    NSInteger age = 10;

归档:

        //创建一个空的二进制数据对象
        NSMutableData *mData = [NSMutableData data];
        
        //创建归档对象
        NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:mData];
        
        //将数据写入归档的对象
        //注意:不同的数据类型用不同的方法
        [archiver encodeObject:name forKey:@"Name"];
        [archiver encodeInteger:age forKey:@"Age"];
        //结束归档
        [archiver finishEncoding];
        
        //生成归档文件
        [mData writeToFile:@"文件路径/test.archive" atomically:YES];
        ```
####解档:       

    NSData *data = [NSData dataWithContentsOfFile:@"文件路径/test.archive"];
    //创建解档对象
    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
    
    //根据key值解档数据，key值必须要和上面自己设定的key一样
    NSString *str = [unarchiver decodeObjectForKey:@"Name"];
    NSInteger age1 = [unarchiver decodeIntegerForKey:@"Age"];
    //结束解档
    [unarchiver finishDecoding];
    
    NSLog(@"%@ %ld", str, age1);

#二、对自定义的类进行归档/解档
####Car.h文件

import

import "Engine.h"

//自定义类归档，需要遵守NSCoding协议，并实现协议中方法
@interface Car : NSObject

@property (nonatomic, copy) NSString *name;
@property (nonatomic, assign) NSInteger speed;
//如果自定义类里有其他自定义类的属性，该作为属性的自定义类页必须遵守NSCoding协议，并且实现其中的方法
@property (nonatomic, retain) Engine *engine;

@end

####Car.m文件

import "Car.h"

@implementation Car

• (void)dealloc
  {
  self.name = nil;
  self.engine = nil;
  [super dealloc];
  }

//归档的时候自动调用encodeWithCoder
//自定义类归档，就是针对类中的成员变量分别归档
//如果自定类中包含其他自定义类，其他自定义类也要遵守NSCoding协议

• (void)encodeWithCoder:(NSCoder *)aCoder{
  [aCoder encodeObject:self.name forKey:@"CarName"];
  [aCoder encodeObject:self.engine forKey:@"Engine"];
  [aCoder encodeInteger:self.speed forKey:@"Speed"];
  }

//解档的时候自动调用initWithCoder

• (instancetype)initWithCoder:(NSCoder *)aDecoder{
  //如果存在继承关系，且父类遵守NSCoding协议，并实现协议中的方法，子类中实现initWithCoder方法时，需要写成self = [super initWithCoder:aDecoder]
  if (self = [super init]) {
  self.name = [aDecoder decodeObjectForKey:@"CarName"];
  // self.engine = [aDecoder decodeObjectForKey:@"Engine"];
  //与上面写法等价
  _engine = [[aDecoder decodeObjectForKey:@"Engine"] retain];
  self.speed = [aDecoder decodeIntegerForKey:@"Speed"];
  }
  return self;
  }

@end

####Engine.h

import

@interface Engine : NSObject

@property (nonatomic, copy) NSString *name;

@end

####Engine.m

import "Engine.h"

@implementation Engine

• (void)dealloc
  {
  self.name = nil;
  [super dealloc];
  }

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

• (instancetype)initWithCoder:(NSCoder *)aDecoder{
  if (self = [super init]) {
  self.name = [aDecoder decodeObjectForKey:@"EngineName"];
  }
  return self;
  }

@end