class userModel: NSObject,NSCoding {
    
    var account: String = ""
    var regmobile: String = ""
    var sec1_question: String = ""

    
    
    func encode(with aCoder: NSCoder) {
        aCoder.encode(account, forKey:"account")
        aCoder.encode(regmobile, forKey:"regmobile")
        aCoder.encode(sec1_question, forKey:"sec1_question")
        aCoder.encode(expert_audit, forKey:"expert_audit")
     
    }
    
    
    required init?(coder aDecoder: NSCoder) {
        super.init()
        account = (aDecoder.decodeObject(forKey:"account")as? String)!   
        status = (aDecoder.decodeObject(forKey:"status")as? String)!
        nickname = (aDecoder.decodeObject(forKey:"nickname")as? String)!
        

    }
  
}

  //  路径：
let userAccountPath = "\(NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true).first!)/southDream.data"




  //归档
            NSKeyedArchiver.archiveRootObject(model, toFile: userAccountPath + "/userModel")


//解档
            if NSKeyedUnarchiver.unarchiveObject(withFile: userAccountPath) != nil {
                
              let  model = NSKeyedUnarchiver.unarchiveObject(withFile: userAccountPath) as? userModel
            }

//归档数据，并用二进制写入文件  
NSMutableData *data = [NSMutableData data];  
NSKeyedArchiver *keyedArchiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];  
[keyedArchiver encodeObject:Users forKey:@"users"];//Users已知的保存用户信息的数组  
[keyedArchiver finishEncoding];  
[data writeToFile:@"归档数据保存路径" atomically:YES];  
[objc] view plain copy print?
//读取上面已经保存好的文件，并反归档后在程序中使用数据  
NSData *newData = [NSData dataWithContentsOfFile:@"归档数据保存路径"];  
NSKeyedUnarchiver *keyedUnArchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:newData];  
NSArray *users = [keyedUnArchiver decodeObjectForKey:@"users"];  
for (User *user in users) {  
    NSLog(@"name = %@  pw = %@",u.name,u.password);  
}  

注意:需要归档的数据中如果含有自定义的对象，那么该对象需遵守<NSCoding>协议，并重写如下方法:
[objc] view plain copy print?
- (void)encodeWithCoder:(NSCoder *)aCoder{  
    [aCoder encodeObject:对象属性 forKey:@"归档的key"];  
}  
[objc] view plain copy print?
- (id)initWithCoder:(NSCoder *)aDecoder{  
    self = [super init];  
    if (self) {  
        实例变量 = [aDecoder decodeObjectForKey:@"归档的key"];  
    }  
    return self;  
}  

@property(nonatomic,copy)NSString *email;
@property(nonatomic,copy)NSString *uid;
@property(nonatomic,copy)NSString *mobile;

#import "UserModel.h"
static UserModel *model;
@implementation UserModel
+(UserModel *)defaultCellModel{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        if (!model) {
            model = [[UserModel alloc]init];
        }
    });
    return model;
}
- (void)encodeWithCoder:(NSCoder *)aCoder{
    [aCoder encodeObject:self.account forKey:@"account"];
    [aCoder encodeObject:self.regmobile forKey:@"regmobile"];
    [aCoder encodeObject:self.sec1_question forKey:@"sec1_question"];

  
    
}

- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder{
    self = [super init];
    
    if(self)
        
    {
        
        self.account = [aDecoder decodeObjectForKey:@"account"];
        
        self.regmobile = [aDecoder decodeObjectForKey:@"regmobile"];
        self.sec1_question = [aDecoder decodeObjectForKey:@"sec1_question"];
        self.headimage = [aDecoder decodeObjectForKey:@"headimage"];
   
        
    }
    
    return self;

}

@end

NSUserDefaults

 保存

Model数据-》归档-》NSUserdefaults 

NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];

//不能直接存取NSObject，需要先归档转成NSData

NSData  *data  = [NSKeyedArchiver archivedDataWithRootObject:model];             

 [defaults setObject:data forKey:@"model"];

NSUserdefaults-》解档-》Model数据

NSData *modeldata = [[NSUserDefaults standardUserDefaults]objectForKey:@"model"];

 usermodel = [NSKeyedUnarchiver unarchiveObjectWithData:modeldata];

／／文件中保存