我一直收到 FileNotFoundException 错误，但我在方法中声明它抛出并包含一个 try/catch 块

Question

如果我修改主要方法类，我可以使这段代码工作，但我应该在不修改它的情况下使它工作。我对导致错误的原因感到困惑。

这是我在课堂上写的方法

   public boolean addSongs(String fileName)throws FileNotFoundException
   {   
      Scanner scan = null;
        
      try //open the try block for FNFE
      { 
      
         //open the file, declare scanner, set endFile to false
         scan = new Scanner(new File(fileName));
         boolean endFile = false;
         
         
         
         while(!endFile) //continues until the end of the file 
         {
            try //try block for mismatch exception or no such element
            {
            
                //scan in line and read through it with new delimiter
               String line = scan.nextLine();
               Scanner read = new Scanner(line);
               read.useDelimiter("/");
               
               //scan in name, minutes, and seconds on the scanned line
               String scannedName = read.next();           
               int scannedMin     = read.nextInt();
               int scannedSec     = read.nextInt();
               
               
               //print the results
               System.out.print("Name:    " + scannedName + "\n" +
                                "Minutes: " + scannedMin + "\n" +
                                "Seconds: " + scannedSec + 
                                "\n-----------------------------------\n");
            
             
             //add to the playlist if no errors
               title.add(new Song(scannedName, scannedMin, scannedSec));
            
            }
            
            catch(InputMismatchException e)  // handle when data is N/A
            {
               String error = scan.nextLine();  //consume the error and return to see where error is      occurring
               System.out.print( " ERROR (cause): " + error + "\n");
              
            }
            
            catch(NoSuchElementException e) // handle when no more data in file
            {
               endFile = true;  //nothing in file set endFile
            }
            
         } //close try block
                  
         //close and return true
         scan.close();
         return true;
         
      }// close loop
            
      //return false if no file found
      catch (FileNotFoundException e)
      {
        System.out.println("THERE IS NO FILE BRETHREN");
         return false;
      }
   
      
   }// close method

这是导致主类出现问题的代码

if (b.addSongs("revolver.txt"))
         System.out.println("Songs in file revolver.txt added successfully");
      System.out.printf("The playlist \"%s\" has a total playing time of %5.2f minutes\n", b.getName(), b.getPlayingTime());
       System.out.printf("It includes the song \"%s\" with a playing time of %4.2f minutes\n", song, b.getPlayingTime(song));
      System.out.printf("The longest song is \"%s\"\n", b.longestSong());
      if (b.removeSong("Taxman"))
         System.out.println("The song \"Taxman\" was removed successfully"); 
      System.out.println("\n" + b); }

这是错误信息：

PLTest.java:32: error: unreported exception FileNotFoundException; must be caught or declared to be thrown
 b.addSongs("revolver.txt");
           ^

我的解决方案是在主类中添加一个 FileNotFoundException 抛出，但正如我之前所说的._。我被禁止更改它。由于调用的方法抛出异常，所以我看不出什么地方一直出错。这是唯一发生的错误，当我将 throw 添加到主类时，一切正常。

附带说明：我试图将 throw 放入另一种方法中，但出现了一个重复的错误，当我删除 throw 时该错误消失了。我不知道这是否相关，但我的下一个猜测是找到一种无需 try/catch 即可更改布尔值的方法？

Answer 1

使用

scan = new Scanner(new FileReader(new File(fileName)));

代替

scan = new Scanner(new File(fileName));

并确保文本文件位于 src 文件夹的旁边。希望异常会解决。