如何“真正”在Java应用程序中绘制图像
我正在尝试使用Java中的图形，创建一个多米诺骨牌游戏。 但是，我遇到了另一个神秘的小“挑战”……我想这次我真的已经退出了IDE
无论如何这里是我的代码：
// In the main class import java.awt.Color; import javax.swing.JFrame; public class GameBoard extends JFrame { public static void main(String[] args) { JFrame game = new JFrame(); game.setTitle("Domino"); game.setSize(800, 600); game.setDefaultCloseOperation(EXIT_ON_CLOSE); game.setBackground(Color.GREEN); Domino double6 = new Domino("images/double_6.png",16,16,'H',6,6); game.add(double6); // Create pieces game.setVisible(true); } } // The game piece class package domino; import java.awt.Color; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import java.util.logging.Level; import java.util.logging.Logger; import javax.imageio.ImageIO; import javax.swing.JPanel; public class Domino extends JPanel { // Instance variables for each piece public int n1, n2, x, y; public char position; // n1 is the first number, n2 is the second number, x and y are coordinates, position refers to horizontal or vertical (ideally would be a different image for each direction) public BufferedImage img = null; public String fileName; // Constructor public Domino(String fileName, int x, int y, char position, int n1, int n2) { this.fileName = fileName; this.x = x; this.y = y; this.n1 = n1; this.n2 = n2; this.position = position; repaint(); } @Override public void paintComponent(Graphics g) { super.paintComponent(g); if (this.position == 'H') { try { // Here's where the trouble appears to rear its ugly head... img = ImageIO.read(new File(fileName)); g.drawImage(img, this.x, this.y, null); } catch (IOException ex) { // This code was generated by the system - it wouldn't even let me do the drawImage code about without a try/catch. Logger.getLogger(Domino.class.getName()).log(Level.SEVERE, null, ex); } } else { // If all else fails I can at least draw the game pieces manually. g.setColor(Color.WHITE); g.fillRect(this.x, this.y, 32, 64); // etc. } } } 无论如何，当我运行它时，我得到了这个：
run: Jul 04, 2013 11:33:13 PM domino.Domino paintComponent SEVERE: null javax.imageio.IIOException: Can't read input file! at javax.imageio.ImageIO.read(ImageIO.java:1301) at domino.Domino.paintComponent(Domino.java:43) at javax.swing.JComponent.paint(JComponent.java:1054) at javax.swing.JComponent.paintChildren(JComponent.java:887) at javax.swing.JComponent.paint(JComponent.java:1063) at javax.swing.JComponent.paintChildren(JComponent.java:887) at javax.swing.JComponent.paint(JComponent.java:1063) at javax.swing.JLayeredPane.paint(JLayeredPane.java:585) at javax.swing.JComponent.paintChildren(JComponent.java:887) at javax.swing.JComponent.paintToOffscreen(JComponent.java:5228) at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:295) at javax.swing.RepaintManager.paint(RepaintManager.java:1236) at javax.swing.JComponent.paint(JComponent.java:1040) at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:39) at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:78) at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:115) at java.awt.Container.paint(Container.java:1967) at java.awt.Window.paint(Window.java:3877) at javax.swing.RepaintManager$3.run(RepaintManager.java:807) at javax.swing.RepaintManager$3.run(RepaintManager.java:784) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:784) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:757) at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:706) at javax.swing.RepaintManager.access$1000(RepaintManager.java:62) at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1651) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:727) at java.awt.EventQueue.access$200(EventQueue.java:103) at java.awt.EventQueue$3.run(EventQueue.java:688) at java.awt.EventQueue$3.run(EventQueue.java:686) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:697) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138) at java.awt.EventDispatchThread.run(EventDispatchThread.java:91) Jul 04, 2013 11:33:14 PM domino.Domino paintComponent SEVERE: null javax.imageio.IIOException: Can't read input file! at javax.imageio.ImageIO.read(ImageIO.java:1301) at domino.Domino.paintComponent(Domino.java:43) at javax.swing.JComponent.paint(JComponent.java:1054) at javax.swing.JComponent.paintChildren(JComponent.java:887) at javax.swing.JComponent.paint(JComponent.java:1063) at javax.swing.JComponent.paintChildren(JComponent.java:887) at javax.swing.JComponent.paint(JComponent.java:1063) at javax.swing.JLayeredPane.paint(JLayeredPane.java:585) at javax.swing.JComponent.paintChildren(JComponent.java:887) at javax.swing.JComponent.paintToOffscreen(JComponent.java:5228) at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:295) at javax.swing.RepaintManager.paint(RepaintManager.java:1236) at javax.swing.JComponent.paint(JComponent.java:1040) at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:39) at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:78) at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:115) at java.awt.Container.paint(Container.java:1967) at java.awt.Window.paint(Window.java:3877) at javax.swing.RepaintManager$3.run(RepaintManager.java:807) at javax.swing.RepaintManager$3.run(RepaintManager.java:784) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:784) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:757) at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:706) at javax.swing.RepaintManager.access$1000(RepaintManager.java:62) at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1651) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:727) at java.awt.EventQueue.access$200(EventQueue.java:103) at java.awt.EventQueue$3.run(EventQueue.java:688) at java.awt.EventQueue$3.run(EventQueue.java:686) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:697) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138) at java.awt.EventDispatchThread.run(EventDispatchThread.java:91) BUILD SUCCESSFUL (total time: 6 seconds)
所以我做了一些研究。 首先，我访问了Java / Oracle网站并找到了关于绘制图像的教程（实际上我的代码非常基于他们的代码，至少是try / catch部分）。 然后我试图删除try / catch事物以查看exception是什么（我99％肯定会有一个，大声笑）。 好吧，我的IDE（NetBeans）通过窃听响应，基本上强迫我使用一个。 然后我进入项目文件夹并检查以确保文件位于正确的位置（它是）。 所以只是为了它，我把它复制到项目中的每个其他文件夹，看看是否会有所帮助。 它没有。
所以很明显我做错了什么，无论出于什么原因，Java都不能或不会读取文件，即使它存在且位置正确（现在每个位置），但我不知道还有什么要做的。
因此，与往常一样，我对任何想法，建议或其他信息持开放态度。 提前致谢。 🙂
如果您将图像/部分从路径中取出，并确保该文件与您的exe在同一目录中会发生什么？ 所以，而不是
Domino double6 = new Domino("images/double_6.png",16,16,'H',6,6);
尝试
Domino double6 = new Domino("double_6.png",16,16,'H',6,6);
这应该检查您运行程序的目录。
检查当前的工作目录： 使用Java获取当前的工作目录 。 它应该是包含images文件夹的文件夹，但可能不是，因此是例外。
错误消息是
javax.imageio.IIOException: Can't read input file!
并且根据堆栈跟踪，当您在Domino.java的第43行中调用ImageIO.read时，它会发生。
确保要加载的文件存在，可读并且相对路径（images / double_6.png）与您执行程序的目录相关。