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这看起来像是一个已解决的老问题，但不幸的是我找不到好的参考。我有一个使用 Javaassist 的 Java 应用程序。在我将其升级为 webstart 应用程序之前，它运行良好。现在Javaassist 给了我一个classNotFoundException。该课程肯定在课程路径中。

我发现这篇相关的帖子https://community.jboss.org/message/302408 有点旧，我无法解码。有人可以帮我看看吗？

谢谢

这是代码片段：

 ctClasses = new HashMap<String, CtClass>();
    classPool = ClassPool.getDefault();

    try {
        ctEntity = classPool.get("org.myclass");
    } catch (NotFoundException e) {
        logger.error("Could not find entity class, this should not happen");
        throw new RuntimeException("Could not find Entity class",e);
    }

堆栈跟踪中没有任何内容。

 java.lang.RuntimeException: Could not find Entity class
    at ca.cbc.panacea.metadata.JavassistClassGeneratorImpl.<init>(JavassistClassGeneratorImpl.java:32)
    at ca.cbc.panacea.metadata.ClassGeneratorFactory.getDefaultClassGenerator(ClassGeneratorFactory.java:12)
    at ca.cbc.panacea.metadata.ClassCreator.<init>(ClassCreator.java:30)
    at ca.cbc.panacea.Panacea.digestMappingFile(Panacea.java:75)
    at ca.cbc.panacea.console.PanaceaConsole.validateMappingFile(PanaceaConsole.java:46)
    at ca.cbc.panacea.console.PanaceaConsoleUI.actionPerformed(PanaceaConsoleUI.java:132)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2028)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2351)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
    at java.awt.Component.processMouseEvent(Component.java:6373)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
    at java.awt.Component.processEvent(Component.java:6138)
    at java.awt.Container.processEvent(Container.java:2085)
    at java.awt.Component.dispatchEventImpl(Component.java:4735)
    at java.awt.Container.dispatchEventImpl(Container.java:2143)
    at java.awt.Component.dispatchEvent(Component.java:4565)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4621)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4282)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4212)
    at java.awt.Container.dispatchEventImpl(Container.java:2129)
    at java.awt.Window.dispatchEventImpl(Window.java:2478)
    at java.awt.Component.dispatchEvent(Component.java:4565)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:679)
    at java.awt.EventQueue.access$000(EventQueue.java:85)
    at java.awt.EventQueue$1.run(EventQueue.java:638)
    at java.awt.EventQueue$1.run(EventQueue.java:636)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
    at java.awt.EventQueue$2.run(EventQueue.java:652)
    at java.awt.EventQueue$2.run(EventQueue.java:650)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:649)
    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)
     Caused by: javassist.NotFoundException: ca.cbc.panacea.metadata.Entity
    at javassist.ClassPool.get(ClassPool.java:436)
    at ca.cbc.panacea.metadata.JavassistClassGeneratorImpl.<init>       (JavassistClassGeneratorImpl.java:29)

问题实际上是ClassLoader。JNLP 使用与 java 命令行不同的类加载器。问题是如何协调 JNLP 类加载器与 Javassist。

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1 回答 1

3

关键是设置ClassPool查看应用程序类的类加载器。这可以通过向 ClassPool 添加类路径来完成：

ctClasses = new HashMap<String, CtClass>();
classPool = ClassPool.getDefault();

//Add the classloader of your application's classes so Javassist can find them
ClassLoader loader = org.MyClass.class.getClassLoader();
pool.appendClassPath(new LoaderClassPath(loader));

try {
    ctEntity = classPool.get("org.MyClass");
} catch (NotFoundException e) {
    logger.error("Could not find entity class, this should not happen");
    throw new RuntimeException("Could not find Entity class",e);
}

您需要为任何不从系统类加载器加载其类的应用程序自定义类池的类路径，例如 web-start 应用程序、Eclipse 插件和在 Java EE 容器下运行的应用程序。

Javassist 教程的类搜索路径部分下的更多详细信息。

于 2012-01-13T01:15:30.050 回答