Java Applet 无法从网络加载图像 [英] Java Applet can't load images from web

问题描述

我已经写了我的第一个 Java 小程序.

I have wrote my first java applet.

它基本上从我的 Django 网络服务器加载一些图像，然后用户可以修改它们.

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

我在 Eclipse 中开发它，我完全没有问题.当我用测试页尝试它时，在 java 控制台上出现此错误:

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) 

被指控的一段代码:

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();}
}

在测试中，我尝试了来自本地网络服务器的图像，但错误出现在所有可能的内部或外部链接中.

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

提前致谢.

推荐答案

除非小程序已签名，否则它将无法访问位于原始服务器之外的其他位置的图像.在这里你可以使用:

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);

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