ios关于数据的存储

本文转载至http://blog.csdn.net/chen505358119/article/details/9278539

            这里我总结了一下数据的存储方式，一是保存在沙盒里创建文件，再把数据写到文件中，二是保存到plist中，三是保存到数据库中.

          1.保存到文件中需要借助NSKeyedArchiver和NSKeyedUnArchiver

          保存数据：                 NSArray*paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,               NSUserDomainMask,YES);          

            NSString *path = [pathsobjectAtIndex:0];

            NSMutableData *data =[[NSMutableData alloc] init];

            NSKeyedArchiver*archiver = [[NSKeyedArchiver alloc]

                                    initForWritingWithMutableData:data];

           [archiver encodeObject:_filleText.text forKey:@"ty"];

           [archiver finishEncoding];

           [data writeToFile:[path stringByAppendingPathComponent:@"test"]

               atomically:YES];

           [archiver release];

           [data release];

           获取数据：

        NSArray *paths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);         

     NSString *path = [pathsobjectAtIndex:0];

     NSMutableData *data =[[NSMutableData alloc] initWithContentsOfFile:

                                  [path stringByAppendingPathComponent:@"test"]];

     NSKeyedUnarchiver *unarchiver =[[NSKeyedUnarchiver alloc]

                                               initForReadingWithData:data];

     NSObject*ret = [[unarchiverdecodeObjectForKey:@"ty"] retain];

     [unarchiver finishDecoding];

     [unarchiver release];

     [data release];

               也可以写成这样只不过前一种进行了序列化：

        保存：   

       NSArray *paths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);        

        NSString *path = [pathsobjectAtIndex:0];

        [NSKeyedArchiver archiveRootObject:_filleText.text toFile:[pathstringByAppendingPathComponent:@"test"]];

                  获取：    

        NSArray *paths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);

     NSString *path = [pathsobjectAtIndex:0];

        NSString* str=[NSKeyedUnarchiver unarchiveObjectWithFile:[pathstringByAppendingPathComponent:@"test"]];

       2.保存到plist文件中

        分为两种一种是保存在系统自带的plist中,另一种是保存在自已创建的plist文件中

        保存到系统自带的plist

       保存:

        [[NSUserDefaults standardUserDefaults] setObject:_filleText.textforKey:@"save"];

        [[NSUserDefaults standardUserDefaults]synchronize];

     获取数据:

      NSString*str=[[NSUserDefaults standardUserDefaults] objectForKey:@"save"];

          保存到自已创的plist中

       保存：

       NSMutableDictionary* dict=[NSMutableDictionarydictionaryWithObjectsAndKeys:@"chen",@"sex",@"liang",@"name",nil];

       NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);

       NSString *docPath = [pathsobjectAtIndex:0];

       NSString *myFile = [docPath stringByAppendingPathComponent:@"user.plist"];

       [dict writeToFile:myFile atomically:YES];

              获取数据:  

      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);

      NSString *docPath = [paths objectAtIndex:0];

      NSString *myFile = [docPath stringByAppendingPathComponent:@"user.plist"];

      NSDictionary* dic = [NSDictionary dictionaryWithContentsOfFile:myFile];

    不过我写着写着，觉得第一种和第二种都差不多，基本上都可以归类为保存数据库到文件中，不同的就是保存到plist中可以打开看到里面的数据，第一种看不到，所以更安全些。

 3.保存数据到数据库里，一般分为两种一种是ios自带的数据库coredata,另一种是sqllite,我想说的是因为sqllite好多和c关联，如果对c不是很熟悉的话，建议用FMDataBase这个第三方库，它是对sqllite的封装，很好用，对于数据库这块下次再写

有什么问题请大家多指教