IOS文件的簡單讀寫實例詳解

數組(可變與不可變)和字典(可變與不可變)中元素對象的類型,必須是NSString,NSArray,NSDictionary,NSData,否則不能直接寫入文件

 #pragma mark---NSString的寫入與讀取---
  //1:獲取路徑
  NSString *docunments = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)firstObject];
  //2:在該路徑下創建文件夾,文件夾名為字符串.txt
  docunments = [docunments stringByAppendingString:@"/字符串.txt"];
  //  NSLog(@"%@",docunments);
  //3:編寫文本內容
  NSString *str = @"大家一起來";
  //4:將文本寫入到"字符串.txt"中
  /*
   writeToFile:文件路徑,在這裡是documents atomically:YES(若為YES,則保證了文件的原子性,即先創建一個臨時文件,直到文件內容寫入成功再導入目標文件(字符串.txt),為NO,直接寫入目標文件裡) encoding:編碼格式是個枚舉值 error:錯誤信息,一般為nil

   */
  BOOL result = [str writeToFile:docunments atomically:YES encoding:NSUTF8StringEncoding error:nil];
  if (result) {
    NSLog(@"我成功了");
  }else{
    NSLog(@"為啥失敗了");
  }

  //讀取
  /*
   stringWithContentsOfFile:路徑 encoding:編碼 error:nil,錯誤信息

   */
  NSString *newStr = [NSString stringWithContentsOfFile:docunments encoding:4 error:nil];
  NSLog(@">>>>%@",newStr);
  /*
   .plist全名是：Property List，屬性列表文件，它是一種用來存儲串行化(當程序徹底退出後,對象就會隨之消亡,但是,我們希望有些東西需要記錄下來,以便於恢復,也可提升用戶體驗,而記錄的這個過程,就叫串行化)後的對象的文件。屬性列表文件的擴展名為.plist ，因此通常被稱為 plist文件。文件是xml格式的。
   注意:plist文件通常用於存儲用戶設置,也可用於存儲捆綁信息
   */
#pragma mark---NSArray的寫入與讀取


//獲取路徑
  NSString *arrayDoc = [SandBox getDocuments];
  //在arrayDoc下拼接文件名
  NSString *arrPath = [arrayDoc stringByAppendingString:@"array.plist"];
  //向數組中寫入數據
  NSArray *array = @[@"25",@"55",@"05",@"5885"];
  //將數組寫入文件
  [array writeToFile:arrPath atomically:YES];
  NSLog(@"數組存入路徑%@",arrPath);

  //讀取
  NSArray *newArray = [NSArray arrayWithContentsOfFile:arrPath];
  NSLog(@"讀取的文件:%@",newArray);
#pragma mark--- 字典的寫入與讀取----
  NSString *dicionaryDic = [SandBox getDocuments];
  NSString *dicpath = [dicionaryDic stringByAppendingString:@"dictionary.plist"];
  NSDictionary *dictionary = @{@"name":@"甲甲",@"age":@"18"};
  [dictionary writeToFile:dicpath atomically:YES];
  NSLog(@"字典存入路徑%@",dicpath);

  //讀取
  NSDictionary *newdict = [NSDictionary dictionaryWithContentsOfFile:dicpath];
  NSLog( @"讀取的字典文件%@",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);
  //讀取
  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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