数据存储(NSCoding)

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NSCoding 是归档与解档的意思.
1.首先要获取存储的沙盒里,必须获取沙盒的路径.

/**沙盒的路径, 要将stu.data文件存储的Documents文件夹中,stringByAppendingPathComponent这个方法不用再拼接"/"*/NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"stu.data"];

/*创建数据模型/
Person 父类属于NSObject
Strudent 子类属于 Person的子类

#import <Foundation/Foundation.h>@interface Person : NSObject<NSCoding>/**这里必须采用NSCoding这个协议*//**姓名*/@property (strong, nonatomic) NSString *name;/**年龄*/@property (assign, nonatomic) NSInteger age;@end/**.m文件,实现NSCoding协议*/#import "Person.h"@implementation Person/**当归档的时候会调用*/- (void)encodeWithCoder:(NSCoder *)aCoder{    /**把属性归档起来,并设置key*/    [aCoder encodeObject:self.name forKey:@"name"];    [aCoder encodeInteger:self.age forKey:@"age"];}/**当解档的时候用调用*/- (id)initWithCoder:(NSCoder *)aDecoder{    if (self = [super init]){    /**根据key解档存储的文件*/    self.name = [aDecoder decodeObjectForKey:@"name"];        self.age = [aDecoder decodeIntegerForKey:@"age"];    }    return self;}@end/**strudent类*/#import <Foundation/Foundation.h>#import "Person.h"@interface Strudent : Person@property (strong, nonatomic) NSString *no;@property (assign, nonatomic) NSInteger store;@end/**.m文件实现NSCoding协议*/#import "Strudent.h"@implementation Strudent/**归档的实现的方法*/- (void)encodeWithCoder:(NSCoder *)aCoder{/**继承父类后,首先要先调用父类的方法传入aCoder*/    [super encodeWithCoder:aCoder];    [aCoder encodeObject:self.no forKey:@"no"];    [aCoder encodeInteger:self.store forKey:@"store"];}/**解档实现的方法*/- (id)initWithCoder:(NSCoder *)aDecoder{- /**继承父类后,首先要先调用父类的方法传入aDecoder*/    if (self = [super initWithCoder:aDecoder]) {       self.store = [aDecoder decodeIntegerForKey:@"store"];       self.no = [aDecoder decodeObjectForKey:@"no"];    }    return self;}@end

保存

 /**新建数据模型*/    Strudent *stu = [[Strudent alloc] init];    stu.name = @"xingzai";    stu.age = 27;    stu.no  = @"68";    stu.store = 100;    [NSKeyedArchiver archiveRootObject:stu toFile:path];    NSLog(@"%@",path);

读取

  Strudent *stu =  [NSKeyedUnarchiver unarchiveObjectWithFile:path];    NSLog(@"%@- %d -- %@ --%d",stu.name,stu.age,stu.no,stu.store);

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