//简单对象可以通过直接写入文件的方式进行存储,复杂对象我们无法直接写入文件,这个时候需要借助归档和反归档

//归档和反归档并不是数据持久化的方式,而是将复杂对象转化成简单对象的一种方式

Person * per = [Person new];
    per.name = @"欧阳冰";
    per.gender = @"神秘";
    per.hobby = @"美女";
    per.age = @"21";
    
    //准备一个路径
    NSString * path = NSHomeDirectory();
    path = [path stringByAppendingString:@"/曹江涛.avi"];
    NSLog(@"%@",path);
    //创建数据对象,用来存放person
    NSMutableData * data = [NSMutableData data];
    //创建归档对象
    NSKeyedArchiver * archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    //归档
    [archiver encodeObject:per forKey:@"secret"];
    //完成归档
    [archiver finishEncoding];
    //写入文件(writeToFile)
    [data writeToFile:path atomically:YES];
    
    //反归档
    NSData * _data = [NSData dataWithContentsOfFile:path];
    //创建反归档对象
    NSKeyedUnarchiver * unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:_data];
    //反归档数据
    Person * per1 = [unarchiver decodeObjectForKey:@"secret"];
    //反归档完成
    [unarchiver finishDecoding];
    NSLog(@"%@",per1.name);

方法二：不用OC封装好的方法，序列化写入

将复杂对象序列化：

eg.将UserListsetNode *node,类型的对象写入文件。

#import <Foundation/Foundation.h>

@interface UserListsetNode : NSObject <NSCoding>//序列化
{
@public
    NSString* m_pstrInfo;//如果服务器异常这边就是错误信息
    NSArray *m_pUsersArray;
    NSMutableDictionary *m_pUserSetDic;
    NSString *m_pstrTime;
}

+(NSData*)Request:(NSString*)pstrToken ToId:(NSString*)pstrToId;
-(BOOL) DecodeJson:(NSData*)pData;

@end

#import "UserListsetNode.h"

@implementation UserListsetNode
+(NSData*)Request:(NSString *)pstrToken ToId:(NSString*)pstrToId{
    NSString *pstrUrl = [NSString stringWithFormat:@"%@%@",BASEURL,@"user/listset/"];
    NSString *pstrData = [NSString stringWithFormat:@"{\"token\":\"%@\",\"toid\":\"%@\"}",pstrToken,pstrToId];
    return [HttpUtil Request:pstrUrl data:pstrData];
}

-(BOOL)DecodeJson:(NSData *)pData{
    m_pstrInfo = @"";

    if (nil == pData)
    {
        return NO;
    }

    NSError *pError;
    NSDictionary *pRetDic = [NSJSONSerialization JSONObjectWithData:pData  options:NSJSONReadingMutableContainers error:&pError];

    if (nil == pRetDic)
    {
        return NO;
    }

    if ([[pRetDic objectForKey:@"status"] integerValue] == 0)
    {
        m_pstrInfo = [pRetDic objectForKey:@"info"];
        return NO;
    }else{
        NSArray *pArray = [[NSArray alloc]init];
        if(nil == m_pUserSetDic)
        {
            m_pUserSetDic = [[NSMutableDictionary alloc]init];
        }
        pArray = [pRetDic objectForKey:@"users"];
        for (NSDictionary *pDic in pArray) {
            for (int i =0; i<pDic.allKeys.count; i++) {
                NSString* pKey = [[pDic allKeys] objectAtIndex:i] ;
                [m_pUserSetDic setValue:[pDic objectForKey:pKey] forKey:pKey];
            }
        }
        m_pstrTime = [pRetDic objectForKey:@"time"];

    }

    return YES;

}
//序列化代码
-(void)encodeWithCoder:(NSCoder *)aCoder{
    [aCoder encodeObject:m_pstrInfo forKey:@"info"];
    [aCoder encodeObject:m_pUsersArray forKey:@"users"];
    [aCoder encodeObject:m_pUserSetDic forKey:@"set"];
    [aCoder encodeObject:m_pstrTime forKey:@"time"];
}

-(id)initWithCoder:(NSCoder *)aDecoder{
    m_pstrInfo = [aDecoder decodeObjectForKey:@"info"];
    m_pUsersArray =[aDecoder decodeObjectForKey:@"users"];
    m_pstrTime = [aDecoder decodeObjectForKey:@"time"];
    m_pUserSetDic = [aDecoder decodeObjectForKey:@"set"];
    return self;
}

@end

使用时：

-(void)SetUserSettings:(UserListsetNode *)pUserSet{
    if ([CommonUtil FileExist:DIR_USERLISTSET]) {
    //将序列化的对象写入文件
        [NSKeyedArchiver archiveRootObject:pUserSet toFile:DIR_USERLISTSET];
        [self GetUserSettings];

    }else{
        [[NSFileManager defaultManager]createFileAtPath:DIR_USERLISTSET contents:nil attributes:nil];
        [self SetUserSettings:pUserSet];
    }
}