数据序列化需要当前类遵循NSCoding协议，该协议有两个方法需要实现

- (instancetype)initWithCoder:(NSCoder *)aDecoder;
//反序列化数据

- (void)encodeWithCoder:(NSCoder *)aCoder;
//序列化数据

举例：

@interface Person : NSObject<NSCoding>

@property (nonatomic, copy)NSString *name;
@property (nonatomic, assign)NSInteger age;

@end

@implementation Person

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

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

@end

调用：

//序列化存储数据
Person *p = [[Person alloc]init];
    p.name = @"keyedArchiver";
    p.age = 30;
    NSString *file = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject stringByAppendingPathComponent:@"personData"];
    [NSKeyedArchiver archiveRootObject:p toFile:file];

//取数据反序列化
NSString *file = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject stringByAppendingPathComponent:@"personData"];
   
    Person *p = [NSKeyedUnarchiver unarchiveObjectWithFile:file];
    if (p) {
        NSLog(@"p.name %@  p.age %ld",p.name,p.age);
    }

如果一个类的属性比较多，请使用runtime来获取类的属性，这样就比较方便。请看示例代码：

#import "Person.h"

@interface Student : Person<NSCoding>

@property (nonatomic, strong)NSString *school;
@end

#import <objc/runtime.h>

@implementation Student
- (instancetype)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        unsigned int count = 0;
        objc_property_t *propertys = class_copyPropertyList(self.class, &count);
        //class_copyPropertyList只能获取到当前类的所有属性，不能获取到父类的属性，所以要调用super initWithCoder.如果想获取类的所有属性和所有成员变量，请使用
        //Ivar *vars = class_copyIvarList(sel.class, &count);
        //Ivar var = vars[0];
//        const char *name = ivar_getName(ivar);
//        NSString *key = [NSString stringWithUTF8String:name];
        
        for (NSInteger i = 0 ; i < count; i++) {
            objc_property_t property = propertys[i];
            const char *propertyNameChar = property_getName(property);
            NSString *propertyNameStr = [NSString stringWithUTF8String:propertyNameChar];
           id value = [aDecoder decodeObjectForKey:propertyNameStr];
            [self setValue:value forKey:propertyNameStr];//kvc
        }
    }
    
    
    return self;
}

- (void)encodeWithCoder:(NSCoder *)aCoder {
    [super encodeWithCoder:aCoder];
    unsigned int count = 0;
    objc_property_t *propertys = class_copyPropertyList(self.class, &count);
    for (NSInteger i = 0 ; i < count; i++) {
        objc_property_t property = propertys[i];
        const char *propertyNameChar = property_getName(property);
        NSString *propertyNameStr = [NSString stringWithUTF8String:propertyNameChar];
        id value = [self valueForKey:propertyNameStr];//kvc
        [aCoder encodeObject:value forKey:propertyNameStr];
    }
    
}

@end

注意点：

如果当前类继承的父类也是有属性的，在序列化与反序列化时需要这样调用

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        self.name = [aDecoder decodeObjectForKey:@"name"];
        self.age = [aDecoder decodeIntegerForKey:@"age"];
    }
    return self;
}

- (void)encodeWithCoder:(NSCoder *)aCoder {
    [super encodeWithCoder:aCoder];
    [aCoder encodeObject:self.name forKey:@"name"];
    [aCoder encodeInteger:self.age forKey:@"age"];
}

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更新时间2018-09-20