数组(可变与不可变)和字典(可变与不可变)中元素对象的类型,必须是NSString,NSArray,NSDictionary,NSData,否则不能直接写入文件

     #pragma mark---NSString的写入与读取---
    //1:获取路径
    NSString *docunments = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)firstObject];
    //2:在该路径下创建文件夹,文件夹名为字符串.txt
    docunments = [docunments stringByAppendingString:@"/字符串.txt"];
   //    NSLog(@"%@",docunments);
    //3:编写文本内容
    NSString *str = @"大家一起来";
    //4:将文本写入到"字符串.txt"中
    /*
     writeToFile:文件路径,在这里是documents atomically:YES(若为YES,则保证了文件的原子性,即先创建一个临时文件,直到文件内容写入成功再导入目标文件(字符串.txt),为NO,直接写入目标文件里) encoding:编码格式是个枚举值 error:错误信息,一般为nil
     
     */
    BOOL result = [str writeToFile:docunments atomically:YES encoding:NSUTF8StringEncoding error:nil];
    if (result) {
        NSLog(@"我成功了");
    }else{
        NSLog(@"为啥失败了");
    }
    
    //读取
    /*
     stringWithContentsOfFile:路径 encoding:编码 error:nil,错误信息
     
     */
    NSString *newStr = [NSString stringWithContentsOfFile:docunments encoding:4 error:nil];
    NSLog(@">>>>%@",newStr);
    

    /*
     .plist全名是：Property List，属性列表文件，它是一种用来存储串行化(当程序彻底退出后,对象就会随之消亡,但是,我们希望有些东西需要记录下来,以便于恢复,也可提升用户体验,而记录的这个过程,就叫串行化)后的对象的文件。属性列表文件的扩展名为.plist ，因此通常被称为 plist文件。文件是xml格式的。
     注意:plist文件通常用于存储用户设置,也可用于存储捆绑信息
     */
#pragma mark---NSArray的写入与读取
    
    
//获取路径
    NSString *arrayDoc = [SandBox getDocuments];
    //在arrayDoc下拼接文件名
    NSString *arrPath = [arrayDoc stringByAppendingString:@"array.plist"];
    //向数组中写入数据
    NSArray *array = @[@"25",@"55",@"05",@"5885"];
    //将数组写入文件
    [array writeToFile:arrPath atomically:YES];
    NSLog(@"数组存入路径%@",arrPath);
    
    //读取
    NSArray *newArray = [NSArray arrayWithContentsOfFile:arrPath];
    NSLog(@"读取的文件:%@",newArray);

#pragma mark--- 字典的写入与读取----
    NSString *dicionaryDic = [SandBox getDocuments];
    NSString *dicpath = [dicionaryDic stringByAppendingString:@"dictionary.plist"];
    NSDictionary *dictionary = @{@"name":@"甲甲",@"age":@"18"};
    [dictionary writeToFile:dicpath atomically:YES];
    NSLog(@"字典存入路径%@",dicpath);
    
    //读取
    NSDictionary *newdict = [NSDictionary dictionaryWithContentsOfFile:dicpath];
    NSLog( @"读取的字典文件%@",newdict);
    
#pragma mark--- NSData----
    NSString *DataPath = [[SandBox getDocuments]stringByAppendingString:@"Data.data"];
//  NSString *string = @"丑八怪";
//    NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
    
    UIImage *image = [UIImage imageNamed:@"2"];
    NSData *data = UIImageJPEGRepresentation(image, 0.5);
    
    [data writeToFile:DataPath atomically:YES];
    NSLog(@"%@",DataPath);
    //读取
    NSData *newData = [NSData dataWithContentsOfFile:DataPath];
//    NSString *new = [[NSString alloc]initWithData:newData encoding:4];
    UIImage *new = [UIImage imageWithData:newData scale:1];
    
    NSLog(@"%@",newData);
    NSLog(@"%@",new);
}