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Eclipse - JAR创建失败“类路径上的类文件找不到或无法访问...”
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Stack Overflow用户
提问于 2013-08-18 23:39:52
回答 8查看 89K关注 0票数 28

我在Eclipse中有一个项目,上面有一个红色的十字,不会导出到可运行的JAR中。我不记得在我的笔记本电脑上重装了Windows之后,我是否看过它,但我知道我没有更改任何代码。在任何一个类中都没有错误,但是我得到的错误指向以下处理Mac OSx上的菜单项的类:

代码语言:javascript
复制
import java.lang.reflect.*;

public class osxhandler implements InvocationHandler {

    protected Object targetObject;
    protected Method targetMethod;
    protected String proxySignature;

    static Object macOSXApplication;

    // Pass this method an Object and Method equipped to perform application shutdown logic
    // The method passed should return a boolean stating whether or not the quit should occur
    public static void setQuitHandler(Object target, Method quitHandler) {
        setHandler(new HOsx("handleQuit", target, quitHandler));
    }


    public static void setAboutHandler(Object target, Method aboutHandler) {
        boolean enableAboutMenu = (target != null && aboutHandler != null);
        if (enableAboutMenu) {
            setHandler(new HOsx("handleAbout", target, aboutHandler));
        }
        // If we're setting a handler, enable the About menu item by calling
        // com.apple.eawt.Application reflectively
        try {
            Method enableAboutMethod = macOSXApplication.getClass().getDeclaredMethod("setEnabledAboutMenu", new Class[] { boolean.class });
            enableAboutMethod.invoke(macOSXApplication, new Object[] { Boolean.valueOf(enableAboutMenu) });
        } catch (Exception ex) {
            System.err.println("MacOSHandler could not access the About Menu");
            ex.printStackTrace();
        }
    }

       public static void setPreferencesHandler(Object target, Method prefsHandler) {
            boolean enablePrefsMenu = (target != null && prefsHandler != null);
            if (enablePrefsMenu) {
                setHandler(new HOsx("handlePreferences", target, prefsHandler));
            }
            // If we're setting a handler, enable the Preferences menu item by calling
            // com.apple.eawt.Application reflectively
            try {
                Method enablePrefsMethod = macOSXApplication.getClass().getDeclaredMethod("setEnabledPreferencesMenu", new Class[] { boolean.class });
                enablePrefsMethod.invoke(macOSXApplication, new Object[] { Boolean.valueOf(enablePrefsMenu) });
            } catch (Exception ex) {
                System.err.println("MacOSHandler could not access the About Menu");
                ex.printStackTrace();
            }
        }

        // Pass this method an Object and a Method equipped to handle document events from the Finder
        // Documents are registered with the Finder via the CFBundleDocumentTypes dictionary in the 
        // application bundle's Info.plist
        public static void setFileHandler(Object target, Method fileHandler) {
            setHandler(new HOsx("handleOpenFile", target, fileHandler) {
                // Override MacOSHandler.callTarget to send information on the
                // file to be opened
                public boolean callTarget(Object appleEvent) {
                    if (appleEvent != null) {
                        try {
                            Method getFilenameMethod = appleEvent.getClass().getDeclaredMethod("getFilename", (Class[])null);
                            String filename = (String) getFilenameMethod.invoke(appleEvent, (Object[])null);
                            this.targetMethod.invoke(this.targetObject, new Object[] { filename });
                        } catch (Exception ex) {

                        }
                    }
                    return true;
                }
            });
        }

        // setHandler creates a Proxy object from the passed MacOSHandler and adds it as an ApplicationListener
        @SuppressWarnings({ "unchecked", "rawtypes" })
        public static void setHandler(HOsx adapter) {
            try {
                Class applicationClass = Class.forName("com.apple.eawt.Application");
                if (macOSXApplication == null) {
                    macOSXApplication = applicationClass.getConstructor((Class[])null).newInstance((Object[])null);
                }
                Class applicationListenerClass = Class.forName("com.apple.eawt.ApplicationListener");
                Method addListenerMethod = applicationClass.getDeclaredMethod("addApplicationListener", new Class[] { applicationListenerClass });
                // Create a proxy object around this handler that can be reflectively added as an Apple ApplicationListener
                Object MacOSHandlerProxy = Proxy.newProxyInstance(HOsx.class.getClassLoader(), new Class[] { applicationListenerClass }, adapter);
                addListenerMethod.invoke(macOSXApplication, new Object[] { MacOSHandlerProxy });
            } catch (ClassNotFoundException cnfe) {
                System.err.println("This version of Mac OS X does not support the Apple EAWT.  ApplicationEvent handling has been disabled (" + cnfe + ")");
            } catch (Exception ex) {  // Likely a NoSuchMethodException or an IllegalAccessException loading/invoking eawt.Application methods
                System.err.println("Mac OS X Adapter could not talk to EAWT:");
                ex.printStackTrace();
            }
        }

        // Each MacOSHandler has the name of the EAWT method it intends to listen for (handleAbout, for example),
        // the Object that will ultimately perform the task, and the Method to be called on that Object
        protected HOsx(String proxySignature, Object target, Method handler) {
            this.proxySignature = proxySignature;
            this.targetObject = target;
            this.targetMethod = handler;
        }

        // Override this method to perform any operations on the event 
        // that comes with the various callbacks
        // See setFileHandler above for an example
        public boolean callTarget(Object appleEvent) throws InvocationTargetException, IllegalAccessException {
            Object result = targetMethod.invoke(targetObject, (Object[])null);
            if (result == null) {
                return true;
            }
            return Boolean.valueOf(result.toString()).booleanValue();
        }

        // InvocationHandler implementation
        // This is the entry point for our proxy object; it is called every time an ApplicationListener method is invoked
        public Object invoke (Object proxy, Method method, Object[] args) throws Throwable {
            if (isCorrectMethod(method, args)) {
                boolean handled = callTarget(args[0]);
                setApplicationEventHandled(args[0], handled);
            }
            // All of the ApplicationListener methods are void; return null regardless of what happens
            return null;
        }

        // Compare the method that was called to the intended method when the MacOSHandler instance was created
        // (e.g. handleAbout, handleQuit, handleOpenFile, etc.)
        protected boolean isCorrectMethod(Method method, Object[] args) {
            return (targetMethod != null && proxySignature.equals(method.getName()) && args.length == 1);
        }

        // It is important to mark the ApplicationEvent as handled and cancel the default behavior
        // This method checks for a boolean result from the proxy method and sets the event accordingly
        protected void setApplicationEventHandled(Object event, boolean handled) {
            if (event != null) {
                try {
                    Method setHandledMethod = event.getClass().getDeclaredMethod("setHandled", new Class[] { boolean.class });
                    // If the target method returns a boolean, use that as a hint
                    setHandledMethod.invoke(event, new Object[] { Boolean.valueOf(handled) });
                } catch (Exception ex) {
                    System.err.println("MacOSHandler was unable to handle an ApplicationEvent: " + event);
                    ex.printStackTrace();
                }
            }
        }    
}

你知道为什么我不能导出/编译吗?我以前从来没有遇到过这个问题。

EN

回答 8

Stack Overflow用户

回答已采纳

发布于 2013-08-18 23:52:52

只需对项目进行清理和/或重建即可。

您可以在Eclipse的Project菜单下找到它。

票数 35
EN

Stack Overflow用户

发布于 2016-03-24 03:39:17

我也有一个不同的,退化的这个问题的例子。原来,我们的项目中有一个类,它有一个文件(所以Eclipse将它保存在类路径中),但在文件中没有定义实际的类(文件只有imports和类注释……可能是合并出了问题)。不管怎样,删除文件解决了这个问题。

票数 8
EN

Stack Overflow用户

发布于 2015-02-14 06:09:28

我在这里被推荐,因为我也犯了同样的错误。我在eclipse上使用maven。我确实右键单击了repo,选择了build path->Conifgure build->Project reference,并检查了我的repo的项目引用。这对我很有效。

票数 0
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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/18300815

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