獲取Java.io.FileNotFoundException;在一個程序中，不知道如何修復

Question

自己製作一個小遊戲作爲一個小項目，我不太擅長錯誤處理等類似問題，所以我得到一個java.io.FileNotFoundException錯誤，我不確定如何進行。

這是我在這裏的第一篇文章，所以我很抱歉如此模糊，我猜我需要拋出異常或以某種方式捕捉它？

import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo) 

public class GameOver extends Actor { 
    public static Counter highScore; 
    public static int currentScore; 
    /** 
    * Act - do whatever the gameOver wants to do. This method is called whenever 
    * the 'Act' or 'Run' button gets pressed in the environment. 
    */ 
    public void act() { 
     displayScore(); 
     if(Greenfoot.isKeyDown("space")) { 
      Greenfoot.setWorld(new City()); 
     } 
    } 
    //This is where I am getting the error 
    private void displayScore() { 
     highScore = new Counter ("HIGHSCORE: "); 
     getWorld().addObject(highScore, 700, 50); //Add width/height 
     highScore.setLocation(City.WIDTH/2, City.HEIGHT/4); 
     currentScore = (0+City.score); 
     int topScore; 
     //The error is coming from this block of code 
     BufferedReader saveFile = new BufferedReader(new FileReader("TextSave.txt")); 
     topScore = Integer.parseInt(saveFile.readLine()); 
     saveFile.readLine(); 
     saveFile.close(); 
     if (topScore < currentScore) { 
      FileWriter writer = new FileWriter("topScore.txt"); 
      writer.write(currentScore); 
      writer.close(); 
     } 
     highScore.setValue(topScore); 
    } 
} 

Answer 1

爲了解決這個問題，我有2項建議

1. 將像d文件的完整路徑：//my_folder//TextSave.txt
2. 將文件放在根目錄你的項目和檢查。

Answer 2

如果你想弄清楚它爲什麼不能找到該文件，把這個代碼：

System.out.println(new File("TextSave.txt").getAbsolutePath()); 

你會看到它試圖打開該文件。

如果要正確處理錯誤，在try/catch塊包裹IO操作：

try(BufferedReader saveFile = new BufferedReader(new FileReader("TextSave.txt"))) { 
    topScore = Integer.parseInt(saveFile.readLine()); 
    saveFile.readLine(); 
} catch(IOException e) { 
    // log the error or show error message here 
} 

Answer 3

你的問題是 「如何捕捉到異常」，這裏是一個答案：

//This is where I am getting the error 
    private void displayScore() { 
     highScore = new Counter ("HIGHSCORE: "); 
     getWorld().addObject(highScore, 700, 50); //Add width/height 
     highScore.setLocation(City.WIDTH/2, City.HEIGHT/4); 
     currentScore = (0+City.score); 
     int topScore; 
     try{ 
      //The error is coming from this block of code 
      BufferedReader saveFile = new BufferedReader(new FileReader("TextSave.txt")); 
      topScore = Integer.parseInt(saveFile.readLine()); 
      saveFile.readLine(); 
      saveFile.close(); 
      if (topScore < currentScore) { 
       FileWriter writer = new FileWriter("topScore.txt"); 
       writer.write(currentScore); 
       writer.close(); 
      } 
      highScore.setValue(topScore); 
     catch(FileNotFoundException e){ 
      // Handle your exception here, like print a message 'the file XXX couldn't be read' 
     } 
    } 

或者你可以將它傳遞給調用函數和處理它有：

private void displayScore() throws FileNotFoundException { 
    ... 
} 

Answer 4

替代，以及更強大的方法（仍然會涉及錯誤處理），將爲目標文件路徑創建一個文件，這將允許您驗證文件的存在，如果它實際上是一個可讀文件等，等等。

這將允許你檢查文件的狀態，並拋出你定義了舒適查明具體此時申請失敗例外：

File file = new File(System.getProperty("user.dir") 
      + "\\GameName\\Saves\\" + textsave.txt"); 
if(!f.exists()) { 
    f.getParentFile().mkdirs(); 
    try { 
     f.createNewFile(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
} 

，並管理您的FileWriter，你以前，或更進一步，編寫代碼來處理讀取/寫入文件：

// just as an example - not complete, runnable code 
BufferedReader bf = new BufferedReader(new InputStreamReader(new FileInputStream(file))); 

FileWriter fw = new FileWriter(file, append); // append is a boolean flag to overwrite/not overwrite the entire content of the file 
BufferedWriter bw = new BufferedWriter(fw); 
bw.write(currentScore); // using your code 

希望這有助於！可能是矯枉過正，可能不是:)