Java applet game has not granted permission to read images

问题

Welcome, I had problem with launching my applet in browser, after few trys I finnaly had run that, i heard music, but the screen was still white, so i run console and i saw that error:

Exception in thread "AWT-EventQueue-2" java.security.AccessControlException: access denied ("java.io.FilePermission" "grass.png" "read")
    at java.security.AccessControlContext.checkPermission(Unknown Source)
    at java.security.AccessController.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkPermission(Unknown Source)
    at sun.plugin2.applet.AWTAppletSecurityManager.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkRead(Unknown Source)
    at sun.awt.SunToolkit.getImageFromHash(Unknown Source)
    at sun.awt.SunToolkit.getImage(Unknown Source)
    at javax.swing.ImageIcon.<init>(Unknown Source)
    at javax.swing.ImageIcon.<init>(Unknown Source)
    at rpg.imgs.loadAndDraw(imgs.java:18)
    at rpg.main.paint(main.java:343)
    at rpg.main.update(main.java:334)
    at sun.awt.RepaintArea.updateComponent(Unknown Source)
    at sun.awt.RepaintArea.paint(Unknown Source)
    at sun.awt.windows.WComponentPeer.handleEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$200(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

It was strange to me because the sound track was playing in background but applet had a problem with loading images. I have put that applet on server: http://skibba.strefa.pl/applet/applet.html If you want to check. I am getting same error as while i was trying to launch the applet in browser from hard drive on my PC.

And if i have no permission, so why the music is playing?

The applet runs in eclipse's Applet:Viewer well - no errors, only in browser is the problem.

回答1:

It was strange to me because the sound track was playing in background but applet had a problem with loading images.

Presuming the image and clip are in the same directory, it suggests the music clip is being loaded by URL from the 'home' location (OK for a sand-boxed applet) while the image is being loaded by File (only possible in a trusted applet, and not suitable for resources we supply for an applet).

Organize to load the image by URL, and it should work.

回答2:

Is kind of explanatory from the errors the application does not have permission to read from a folder where the png is stored. Applets are by default denied from accessing the Local directory. You need to sign your applet or edit the policy.

http://www.coderanch.com/how-to/java/HowCanAnAppletReadFilesOnTheLocalFileSystem

i hope it helped.

来源：https://stackoverflow.com/questions/18390303/java-applet-game-has-not-granted-permission-to-read-images