java - 类未找到异常 : Server

Question

我遇到了标题中提到的问题。我想做的是编译我的服务器类并在我的主类运行时执行它。

这是我的主类中的 runServer 方法

    public static void runServer() throws Exception{

    File sourceFile = new File("/Users/Joel/NetbeansProjects/FYP/src/ui_v2/Server.java");
    JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
    StandardJavaFileManager fileMgr = compiler.getStandardFileManager(null, null, null);
    fileMgr.setLocation(StandardLocation.CLASS_OUTPUT, Arrays.asList(new File("/Users/Joel/NetbeansProjects/FYP/src/ui_v2")));

    compiler.getTask(null, fileMgr, null, null, null, 
            fileMgr.getJavaFileObjectsFromFiles(Arrays.asList(sourceFile)));
    fileMgr.close();

    try {
        Class params[] = {};
        Object paramsObj[] = {};
        Class thisClass = Class.forName("Server");
        Method thisMethod = thisClass.getMethod("main", params);
        thisMethod.invoke(thisClass, paramsObj);
    }
    catch (Exception e) {
        e.printStackTrace();
    }  
}

这是我的 ui_v2 文件夹中文件的屏幕截图。 这是我的错误:

java.lang.ClassNotFoundException: Server
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:260)
at ui_v2.GenerateChat.runServer(GenerateChat.java:353)
at ui_v2.GenerateChat.Btn_ConfirmActionPerformed(GenerateChat.java:230)
at ui_v2.GenerateChat.access$000(GenerateChat.java:26)
at ui_v2.GenerateChat$1.actionPerformed(GenerateChat.java:129)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6525)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6290)
at java.awt.Container.processEvent(Container.java:2234)
at java.awt.Component.dispatchEventImpl(Component.java:4881)
at java.awt.Container.dispatchEventImpl(Container.java:2292)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
at java.awt.Container.dispatchEventImpl(Container.java:2278)
at java.awt.Window.dispatchEventImpl(Window.java:2739)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746)
at java.awt.EventQueue.access$400(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:697)
at java.awt.EventQueue$3.run(EventQueue.java:691)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:719)
at java.awt.EventQueue$4.run(EventQueue.java:717)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:716)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

如您所见，提到的Server.class位于sourceFile中文件路径中写入的文件夹中。所以我不知道我当前的代码不起作用，而是给了我一个异常(exception)。

Answer 1

使用 Class.forName("Server") 您的类路径应设置为 ui_v2 文件夹，否则您需要使用包提供名称，直到设置类路径。假设你的类路径设置为 src 你需要给出类似的路径Class.forName("ui_v2.Server")

更新:- 另外，主要方法没有以正确的方式调用。应该是

Method thisMethod = thisClass.getMethod("main", String[].class);
thisMethod .invoke(null,  params);// static method doesn't have an instance

如果您不想传递任何参数，可以将参数传递为 null