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I am trying to build a Java applet, called game, which is something I have never done before (I've always just built standalone applications). My applet works fine when I test it in Eclipse, but when I try putting it on my website, I get the following error in the console:

java.lang.reflect.InvocationTargetException
    at com.sun.deploy.util.DeployAWTUtil.invokeAndWait(DeployAWTUtil.java:116)
    at sun.plugin2.applet.Plugin2Manager.runOnEDT(Plugin2Manager.java:3541)
    at sun.plugin2.applet.Plugin2Manager.createApplet(Plugin2Manager.java:3072)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Plugin2Manager.java:1497)
    at java.lang.Thread.run(Thread.java:680)
Caused by: java.security.AccessControlException: access denied (java.util.PropertyPermission user.dir read)
    at java.security.AccessControlContext.checkPermission(AccessControlContext.java:374)
    at java.security.AccessController.checkPermission(AccessController.java:546)
    at java.lang.SecurityManager.checkPermission(SecurityManager.java:532)
    at java.lang.SecurityManager.checkPropertyAccess(SecurityManager.java:1285)
    at java.lang.System.getProperty(System.java:667)
    at java.io.UnixFileSystem.resolve(UnixFileSystem.java:118)
    at java.io.File.getAbsolutePath(File.java:501)
    at game.<init>(game.java:117)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at java.lang.Class.newInstance0(Class.java:355)
    at java.lang.Class.newInstance(Class.java:308)
    at sun.plugin2.applet.Plugin2Manager$13.run(Plugin2Manager.java:3060)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:199)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:682)
    at java.awt.EventQueue.access$000(EventQueue.java:85)
    at java.awt.EventQueue$1.run(EventQueue.java:643)
    at java.awt.EventQueue$1.run(EventQueue.java:641)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:652)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception: java.lang.reflect.InvocationTargetException

It says access denied (java.util.PropertyPermission user.dir read), but I can't figure out where it's trying to read something off the user's file system.

It also says at game.<init>(game.java:117), but I went into my file and made a message output to the console on line 114 and it never got written. I then figured that maybe it was looking at line 117 inside public game(), so I looked for that and it was the start of a listener for a Mouse event. It made sense to me that this would be something that Java would need permission to read, so I deleted all of it and then deleted all the imports for good measure. Then I cleared both Chrome and Java's caches and retried. Same error.

  1. What does this mean, am I interpreting it incorrectly?
  2. When it says that line 117, what is it line 117 of?
  3. Why would this be happening?
  4. How can I fix it?
  5. How can I prevent it in the future?

For reference, here is the code for public game():

public game() throws MalformedURLException{

    JPanel board = new chessboard();
    board.setSize(320, 320);
    board.setLocation(0, 0);

    System.out.println("Got this far");

    Piece wp1 = new Piece(wpawn, a2);
...
    Piece bk = new Piece(bking, e8);


    board.add(wp1);
...
    board.add(bk);

    wp1.setLocation(wp1.square.getPoint());
...     
    bk.setLocation(bk.square.getPoint());

    add(board);
    repaint();

    addMouseListener(new MouseAdapter(){
        public void mousePressed(MouseEvent evt){

            for (int i = 0; i < 8; i++){
                for (int j = 0; j < 8; j++){
                    if (squares[i][j].piece != null)
                        System.out.println(squares[i][j].getPointString() + ": " + squares[i][j].piece.type);
                }
            }

            Point p = evt.getPoint();
            if (0 < p.x && p.x < 319 && 0 < p.y && p.y < 319){
                Square clicked = getSquare(p);
                System.out.println("up: " + clicked.getPointString());
                if (clicked.piece != null){
                    pickedUp = true;
                    pickedUpPiece = clicked.piece;
                }
            }
        }
        public void mouseReleased(MouseEvent evt){
            if (pickedUp){
                Point p = evt.getPoint();
                if (0 < p.x && p.x < 319 && 0 < p.y && p.y < 319){
                    System.out.println("down: " + getSquare(p).getPointString());
                    movePiece(pickedUpPiece, getSquare(p).getColumn(), getSquare(p).getRow());
                }
                pickedUp = false;
            }
            else System.out.println("Not picked up");
        }
    });
}
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1 回答 1

3

The key output of the stack trace is:

at java.io.File.getAbsolutePath(File.java:501)
at game.<init>(game.java:117)

This means that your game.java file, at line 117, is calling getAbsolutePath() on something. Java applets embedded in a browser are not permitted to access the local filesystem.

于 2012-05-13T00:03:08.607 回答