无法从命令行运行 Swing [英] can't run swing from the command line

问题描述

我在windows中使用命令行编译然后执行我的java程序.我去了 http://java.sun.com/docs/books/tutorial/uiswing/start/compile.html 并尝试编译 HelloWorldSwing.java 类.它有效，但是当我尝试java HelloWorldSwing"时，它给了我一堆错误，并在线程main"java.lang.NoClassDefFoundError:HelloWorldSwing(错误名称:start/HelloWorldSwing)中说出了一些类似异常的内容

i use the command line in windows to compile and then execute my java programs. i've gone to http://java.sun.com/docs/books/tutorial/uiswing/start/compile.html and tried compiling the HelloWorldSwing.java class. it worked, but when i try "java HelloWorldSwing" it gives me a bunch of erros and says something along the lines of Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorldSwing (wrong name: start/HelloWorldSwing)

我尝试使用 java start/HelloWorldSwing 运行，它显示 noClassDefFoundError.我也没有遇到 javac 错误.这是教程中的代码:

i try running with java start/HelloWorldSwing and it says noClassDefFoundError. i get no errors with javac either. here's the code from the tutorial:

import javax.swing.*;        

public class HelloWorldSwing {
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("HelloWorldSwing");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Add the ubiquitous "Hello World" label.
        JLabel label = new JLabel("Hello World");
        frame.getContentPane().add(label);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

使用 javaw

弹出窗口

发生java异常"

另一个窗口

"错误:找不到主类.错误:发生了 jni 错误，请检查您的安装并重试."

"error: could not find the main class. error: a jni error has occurred, please check your installation and try again."

在运行任何 Java 程序时从未遇到过任何问题，我是否遗漏了什么?有没有办法知道它是什么?

never had any problems running any java programs, am i missing something? is there a way to know what it is?

我也在 .java 和 .class 所在的同一路径中运行命令.

i'm also running the command in the same path where the .java and .class are.

在我编译程序的路径中没有文件夹开始.

there is no folder start in the path where i compiled the program.

编辑2我用 java 尝试了 start/HelloWorldSwing 和 HelloWorldSwing.

EDIT2 I tried both start/HelloWorldSwing and HelloWorldSwing with java.

javac 也没有出现任何错误.当我使用 javaw 和 java 给我 NoClassDefFoundException，然后谈论 ClassLoaders 和诸如此类的东西时，我得到了 2 个带有我之前键入的消息的弹出窗口.

I don't get any errors with javac also. I get 2 pop up windows with the messages I've typed previously when I use javaw and java gives me the NoClassDefFoundException, then talks about the ClassLoaders and whatnot.

编辑3我通过删除包启动"来让它工作.线.我该怎么做才能让它发挥作用?

EDIT3 I got it to work by removing the "package start;" line. what would i have to do to make it work with that?

javaw 现在也可以使用，因为我删除了包行.

javaw also works now that I removed the package line.

推荐答案

是的.该页面有一个小错误:

Yep. That page has a slight bug:

该类使用了一个包，但在运行说明中没有使用该包

The class uses a package, but in the run instructions the package is not used

你可以做两件事:

a) 删除包名(删除行 pacakge start;)并按指示运行

a) Drop the package name (delete the line pacakge start;) and run as indicated

或者

b) 保留代码中的 package start; 行并将 -d 选项附加到 javac 并使用完整的类名.

b) Leave the package start; line in the code and append the -d option to javac and use the full class name.

我希望这会有所帮助.

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