Java ImageIO異常

Question

雖然運行代碼來顯示pacman級別的背景，但我遇到了圖像和pacman sprite未加載的問題。

例外：

Exception in thread "Thread-2" java.lang.IllegalArgumentException: input == null! 
    at javax.imageio.ImageIO.read(ImageIO.java:1388) 
    at org.pacman.Pacman.init(Pacman.java:51) 
    at org.game.engine.GameLoop.run(GameLoop.java:26) 

線GameLoop 26是簡單地game.init();。

這裏是類：

public class Pacman extends Game { 

    public static void main(String[] args) { 
     GameApplication.start(new Pacman()); 
    } 

    private BufferedImage sheet; 
    private int frame; 

    public Pacman() { 
     title = "Pacman"; 
     width = 176; 
     height = 258; 
     frame = 0; 
    } 

    @Override 
    public void draw(Graphics g) { 
     if (sheet != null) { 
      g.drawImage(sheet, -2, 0, null); 
      //draw ms pacman 
      g.drawImage(sheet.getSubimage(628+(frame/3)*(15+2), 33, 15, 15), 80, 105, null); 
     } 
    } 

    @Override 
    public void init() { 
     try { 
      sheet = ImageIO.read(Pacman.class.getResource("/images/pacman.png")); 
     } catch (IOException ex) { 
      Logger.getLogger(Pacman.class.getName()).log(Level.SEVERE, null, ex); 
     } 
    } 

    @Override 
    public void update() { 
     frame++; 
     if (frame > 3*2) { 
      frame = 0; 
     } 
    } 
} 

Answer 1

嘗試調用ImageIO.read與getResourceAsStream，但檢查InputStream爲null提前。你會發現它確實是null。這意味着無法在該URI處檢索圖像。

Answer 2

在org.pacman.Pacman.init（Pacman.java:51）

所以看線51：

sheet = ImageIO.read(Pacman.class.getResource("/images/pacman.png")); 

所以Pacman.class.getResource("/images/pacman.png")是null，所以它看起來像它的不加載圖像。