Eclipse - JAR创建失败“Classpath找不到或不可访问的类文件” [英] Eclipse - JAR creation failed "Class files on classpath not found or not accessible for..."
本文介绍了Eclipse - JAR创建失败“Classpath找不到或不可访问的类文件”的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
import java.lang.reflect。*;
public class osxhandler implements InvocationHandler {
protected Object targetObject;
protected方法targetMethod;
protected String proxySignature;
static Object macOSXApplication;
//传递此方法一个对象和方法配置执行应用程序关闭逻辑
//传递的方法应该返回一个布尔值，表示退出是否应该发生
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））;
}
//如果我们正在设置一个处理程序，通过调用
// com.apple.eawt.Application反映出
尝试关闭菜单项{
方法enableAboutMethod = macOSXApplication.getClass（）。getDeclaredMethod（setEnabledAboutMenu，new Class [] {boolean.class}）;
enableAboutMethod.invoke（macOSXApplication，new Object [] {Boolean.valueOf（enableAboutMenu）}）;
} catch（Exception ex）{
System.err.println（MacOSHandler无法访问关于菜单）;
ex.printStackTrace（）;
}
}
public static void setPreferencesHandler（Object target，Method prefsHandler）{
boolean enablePrefsMenu =（target！= null&& prefsHandler！= null ）;
if（enablePrefsMenu）{
setHandler（new HOsx（handlePreferences，target，prefsHandler））;
}
//如果我们设置一个处理程序，通过调用
// com.apple.eawt.Application反映
尝试{
方法enablePrefsMethod = macOSXApplication.getClass（）。getDeclaredMethod（setEnabledPreferencesMenu，new Class [] {boolean.class}）;
enablePrefsMethod.invoke（macOSXApplication，new Object [] {Boolean.valueOf（enablePrefsMenu）}）;
} catch（Exception ex）{
System.err.println（MacOSHandler无法访问关于菜单）;
ex.printStackTrace（）;
}
}
//传递此方法一个对象和一个方法，用于处理来自Finder的文档事件
//文档通过
中的CFBundleDocumentTypes字典//应用程序包的Info.plist
public static void setFileHandler（Object target，Method fileHandler）{
setHandler（new HOsx（handleOpenFile，target，fileHandler）{
//覆盖MacOSHandler.callTarget以发送
//要打开的文件的信息
public boolean callTarget（Object appleEvent）{
if（appleEvent！= null）{
try {
方法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从传递的MacOSHandler创建一个Proxy对象，并将其添加为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）;
}
类applicationListenerClass = Class.forName（com.apple.eawt.ApplicationListener）;
方法addListenerMethod = applicationClass.getDeclaredMethod（addApplicationListener，new Class [] {applicationListenerClass}）;
//在这个处理程序周围创建一个代理对象，可以反映性地添加为Apple ApplicationListener
对象MacOSHandlerProxy = Proxy.newProxyInstance（HOsx.class.getClassLoader（），new Class [] {applicationListenerClass}，adapter ）;
addListenerMethod.invoke（macOSXApplication，new Object [] {MacOSHandlerProxy}）;
} catch（ClassNotFoundException cnfe）{
System.err.println（此版本的Mac OS X不支持Apple EAWT。ApplicationEvent处理已禁用（+ cnfe +））;
} catch（Exception ex）{//可能是NoSuchMethodException或者IllegalAccessException加载/调用eawt.Application方法
System.err.println（Mac OS X Adapter can not talk to EAWT：）;
ex.printStackTrace（）;
}
}
//每个MacOSHandler都有其打算侦听的EAWT方法的名称（例如，handleAbout），
//对象将最终执行任务，并且该方法被调用该对象
受保护的HOsx（String proxySignature，Object target，Method handler）{
this.proxySignature = proxySignature;
this.targetObject = target;
this.targetMethod = handler;
}
//覆盖此方法对事件执行任何操作
//随各种回调
//参见上面的setFileHandler一个例子
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实现
//这是我们的代理对象的入口点;每次调用ApplicationListener方法时调用它
public Object invoke（Object proxy，Method method，Object [] args）throws Throwable {
if（isCorrectMethod（method，args））{
boolean handling = callTarget（args [0]）;
setApplicationEventHandled（args [0]，处理）;
}
//所有的ApplicationListener方法都是void;不管发生什么，返回null
返回null;
}
//当创建MacOSHandler实例时，比较调用的方法到目标方法
//（例如handleAbout，handleQuit，handleOpenFile等）
protected boolean isCorrectMethod（Method method，Object [] args）{
return（targetMethod！= null&& proxySignature.equals（method.getName（））&& args.length == 1） ;
}
//将ApplicationEvent标记为已处理并取消默认行为非常重要
//此方法从代理方法检查布尔值结果并设置事件因此
protected void setApplicationEventHandled（Object event，boolean processed）{
if（event！= null）{
try {
方法setHandledMethod = event.getClass（）。getDeclaredMethod（ setHandled，新的Class [] {boolean.class}）;
//如果目标方法返回一个布尔值，则将其用作提示
setHandledMethod.invoke（event，new Object [] {Boolean.valueOf（processed）}）;
} catch（Exception ex）{
System.err.println（MacOSHandler无法处理ApplicationEvent：+事件）;
ex.printStackTrace（）;
}
}
}
}
任何想法为什么我不能导出/编译？
解决方案
只需对项目进行干净和/或重建。
您可以在Eclipse的项目菜单下找到它。
I have a project in Eclipse which has a red cross on it and will not export to a runnable JAR. I can't remember if I have looked at it since I reinstalled Windows on my laptop, but I know that I haven't changed any code. There are no errors in any of the classes, however the error I get points to the following class which deals with the menu items on Mac OSx:
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();
}
}
}
}
Any ideas as to why I can't export/compile? I've never had this issue before
解决方案
Just do a clean and/or rebuild on the project.
You can find it under the Project menu of Eclipse.
这篇关于Eclipse - JAR创建失败“Classpath找不到或不可访问的类文件”的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
