IOS文件的简单读写实例详解

IOS文件的简单读写实例详解

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);
}

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