Java Applet can't load images from web

问题

I have wrote my first java applet.

It basically loads some images from my Django webserver and then the user can modify them.

I developed it in Eclipse, and I had no problems at all. When I tried it with a test page, on the java console come out this error:

java.security.AccessControlException: access denied (java.net.SocketPermission www.hyros.net resolve)
    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.checkConnect(SecurityManager.java:1031)
    at sun.plugin2.applet.Applet2SecurityManager.checkConnect(Applet2SecurityManager.java:500)
    at sun.plugin2.applet.Plugin2Manager$AppletContextImpl.getImage(Plugin2Manager.java:2718)
    at java.applet.Applet.getImage(Applet.java:242)
    at MapGenerator.getResourceImage(MapGenerator.java:50)
    at MapGenerator.init(MapGenerator.java:35)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Plugin2Manager.java:1637)
    at java.lang.Thread.run(Thread.java:662)
Eccezione: java.security.AccessControlException: access denied (java.net.SocketPermission www.hyros.net resolve)

The incriminated piece of code:

for(int i=0; i< numero_immagini; i++) {
    try {
        URL url = new URL(this.getParameter(IMMAGINE+i));
        images[i] = ImageIO.read(url);
        floors[i] = Integer.parseInt(this.getParameter(PIANO_IMMAGINE+i));
    } catch (IOException ioe) {ioe.printStackTrace();}
}

For the test i tried an image from my local webserver, but the error comes out with every possible link, internal or external.

Thank you in advance.

回答1:

Unless the applet is signed, it will not be able to access images at a different location other then that of the originating server. Here you could use:

images[i] = getImage(getDocumentBase(), IMMAGINE + i);

回答2:

Ok, Solved it!

The line of code to change is

URL url = new URL(this.getParameter(IMMAGINE+i));

URL url = new URL(getCodeBase(), this.getParameter(IMMAGINE+i));

来源：https://stackoverflow.com/questions/12624572/java-applet-cant-load-images-from-web

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java

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applet