使用LWJGL / Slick2d小程序加载图像/声音

Question

尝试在Applet上加载图像或声音时出现问题。 我对applet和Slick2d使用LWJGL加载图像/声音。 但是，当我使用Netbeans启动applet时，没有问题...我使用了用于加载声音的代码：

public class Files {
    public static Audio sound;

    public static void load() {
        try {
            sound = AudioLoader.getAudio("WAV", ResourceLoader.getResourceAsStream("/snd/Tir1-16b.wav"));
        } catch (IOException ex) {
            Logger.getLogger(Files.class.getName()).log(Level.SEVERE, null, ex);
        }

        System.out.println("loaded with success !");
    }
}

还有HTML页面：

<applet code="org.lwjgl.util.applet.AppletLoader" archive="lwjgl_util_applet.jar" codebase="." width="800" height="600">

    <!-- The following tags are mandatory -->

    <!-- Name of Applet, will be used as name of directory it is saved in, and will uniquely identify it in cache -->
    <param name="al_title" value="appletloadertest">

    <!-- Main Applet Class -->
    <param name="al_main" value="myapps.MyApps">

    <!-- List of Jars to add to classpath -->
    <param name="al_jars" value="lwjgl_applet.jar, lwjgl.jar, jinput.jar, lwjgl_util.jar MyApps.jar">

    <!-- signed windows natives jar in a jar --> 
    <param name="al_windows" value="windows_natives.jar">

    <!-- signed linux natives jar in a jar --> 
    <param name="al_linux" value="linux_natives.jar">

    <!-- signed mac osx natives jar in a jar --> 
    <param name="al_mac" value="macosx_natives.jar">

    <!-- signed solaris natives jar in a jar --> 
    <param name="al_solaris" value="solaris_natives.jar">

    <!-- Tags under here are optional -->

    <!-- whether to use cache - defaults to true -->
    <!-- <param name="al_cache" value="true"> -->

    <!-- Version of Applet (case insensitive String), applet files not redownloaded if same version already in cache -->
    <!-- <param name="al_version" value="0.1"> -->

    <!-- Specify the minimum JRE version required by your applet, defaults to "1.5" -->
    <!-- <param name="al_min_jre" value="1.6"> -->

    <!-- background color to paint with, defaults to white -->
    <!-- <param name="boxbgcolor" value="#000000"> -->

    <!-- foreground color to paint with, defaults to black -->
    <!-- <param name="boxfgcolor" value="#ffffff"> -->

    <!-- logo to paint while loading, will be centered, defaults to "appletlogo.gif" -->
    <!-- <param name="al_logo" value="appletlogo.gif"> -->

    <!-- progressbar to paint while loading. Will be painted on top of logo, width clipped to percentage done, defaults to "appletprogress.gif" -->
    <!-- <param name="al_progressbar" value="appletprogress.gif"> -->

    <!-- whether to run in debug mode -->
    <!-- <param name="al_debug" value="true"> -->

    <!-- whether to prepend host to cache path - defaults to true -->
    <!-- <param name="al_prepend_host" value="true"> -->

    <param name="separate_jvm" value="true">
  </applet>

当我使用applet启动HTML页面时，控制台日志显示了什么：

null
java.lang.reflect.InvocationTargetException
    at java.awt.EventQueue.invokeAndWait(Unknown Source)
    at java.awt.EventQueue.invokeAndWait(Unknown Source)
    at org.lwjgl.util.applet.AppletLoader.run(AppletLoader.java:906)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoClassDefFoundError: org/newdawn/slick/util/ResourceLoader
    at myapps.Files.load(Files.java:24)
    at myapps.MyApps.init(MyApps.java:32)
    at org.lwjgl.util.applet.AppletLoader.switchApplet(AppletLoader.java:1330)
    at org.lwjgl.util.applet.AppletLoader$2.run(AppletLoader.java:909)
    at java.awt.event.InvocationEvent.dispatch(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.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)
Caused by: java.lang.ClassNotFoundException: org.newdawn.slick.util.ResourceLoader
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 18 more

null肯定意味着变量Audio为null。 这也意味着可能找不到该文件...因此，我尝试将目录“ snd”和“ sprites”放在applet目录以及我的applet的.jar上，但没有任何反应...

谁能帮助我？ 我花了很多时间试图在许多论坛上也找到这种问题，但是没人帮助我...

非常感谢 ！

Answer 1

感谢您的回答。 我通过在HTML页面中添加“ slick.jar”来解决NoClassDefFoundError的问题，如下所示：

<param name="al_jars" value="MyApps.jar lwjgl_applet.jar, lwjgl.jar, jinput.jar, lwjgl_util.jar slick.jar">

但是现在我有另一个问题：

This occurred while 'Initializing real applet'
access denied ("java.io.FilePermission" ".\snd\Tir1-16b.wav" "read")
java.security.AccessControlException: access denied ("java.io.FilePermission" ".\snd\Tir1-16b.wav" "read")
    at java.security.AccessControlContext.checkPermission(Unknown Source)
    at java.security.AccessController.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkRead(Unknown Source)
    at java.io.File.exists(Unknown Source)
    at org.newdawn.slick.util.FileSystemLocation.getResourceAsStream(FileSystemLocation.java:52)
    at org.newdawn.slick.util.ResourceLoader.getResourceAsStream(ResourceLoader.java:61)
    at myapps.Files.load(Files.java:24)
    at myapps.MyApps.init(MyApps.java:32)
    at org.lwjgl.util.applet.AppletLoader.switchApplet(AppletLoader.java:1330)
    at org.lwjgl.util.applet.AppletLoader$2.run(AppletLoader.java:909)
    at java.awt.event.InvocationEvent.dispatch(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.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)

我已经阅读了很多有关此问题的内容，并且尝试使用以下命令对MyApps.jar进行签名：

keytool -genkey -keyalg rsa -alias key
keytool -export -alias key -file cert.crt
jarsigner MyApps.jar key

签名者之所以能够工作，是因为现在我可以在MyApps.jar的META-INF上看到文件“ KEY.RSA”和“ KEY.SF”。 但是问题仍然在这里...

我需要一些帮助，我只是不了解这个问题...

谢谢 ！