运行helloworld + classpath问题时出错

Question

我正在编译helloworldapp而没有错误.

我正在Windows上运行java helloworldapp

CLASSPATH:.; C:\ Program Files\Java\jre7\lib;

JAVA_HOME:C:\ Program Files\Java\jre7

路径包括C:\ Program Files\Java\jdk1.7.0\bin \

结果:

C:\Users\k\Desktop\abcl-bin-0.26.2>java helloworldapp
Exception in thread "main" java.lang.NoClassDefFoundError: helloworldapp (wrong
name: HelloWorldApp)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
............etc

好吧,对于一些共鸣,它找不到类,所以我试图手动完成.

C:\Users\k\Desktop\abcl-bin-0.26.2>java -cp "C:\Program Files\Java\jre7\lib" helloworldapp
Error: Could not find or load main class helloworldapp

C:\Users\k\Desktop\abcl-bin-0.26.2>java -cp C:\Program Files\Java\jre7\lib; helloworldapp
Error: Could not find or load main class Files\Java\jre7\lib;

我究竟做错了什么？我看过几个论坛,但他们并没有特别的帮助.

更新,我超越了helloworld阶段.现在真正的问题

import org.armedbear.lisp.*;

public class Main
{

    public static void main(String[] argv)
    {
    try
        {
        Main thisObject = new Main();
        Interpreter interpreter = Interpreter.createInstance();
        interpreter.eval("(load \"lispfunctions.lisp\")");
        org.armedbear.lisp.Package defaultPackage = 
            Packages.findPackage("CL-USER");
        Symbol voidsym = 
            defaultPackage.findAccessibleSymbol("VOID-FUNCTION");
        Function voidFunction = (Function) voidsym.getSymbolFunction();
        voidFunction.execute(new JavaObject(thisObject));
        }
    catch (Throwable t)
        {
        System.out.println("exception!");
        t.printStackTrace();
        }
    }
    public int addTwoNumbers(int a, int b)
    {
    return a + b;
    }
}

我试过了两个

C:\Users\k\Desktop\abcl-bin-0.26.2>java -cp abcl.jar Main
Error: Could not find or load main class Main

C:\Users\k\Desktop\abcl-bin-0.26.2>java -cp abcl.jar main
Error: Could not find or load main class main

abcl.jar位于同一文件夹中

一些更多的试验和错误

C:\Users\k\Desktop\abcl-bin-0.26.2>java -cp .:abcl.jar Main
Error: Could not find or load main class Main

C:\Users\k\Desktop\abcl-bin-0.26.2>java Main -cp .:abcl.jar
Exception in thread "main" java.lang.NoClassDefFoundError: org/armedbear/lisp/Li
spObject
        at java.lang.Class.getDeclaredMethods0(Native Method)
        at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
        at java.lang.Class.getMethod0(Unknown Source)
        at java.lang.Class.getMethod(Unknown Source)
        at sun.launcher.LauncherHelper.getMainMethod(Unknown Source)
        at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
Caused by: java.lang.ClassNotFoundException: org.armedbear.lisp.LispObject
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        ... 6 more

Answer 1

在java中编写类时,文件名必须与类的名称匹配.

class HelloWorldApp {
    public static void main(String[] args) {
        System.out.println("Hello world");
    }

}

必须保存为HelloWorldApp.java
它必须匹配大小写,即helloworldapp.java不起作用.

当您需要运行该类时,必须使用正确的大小写来引用它.

java HelloWorldApp

但不是

java helloworldapp

如果要引用JAR,则需要将其添加到类路径中.默认情况下,类路径由当前工作目录中的文件组成.在Windows上,类路径是一个分号(;)分隔列表,在Linux和Mac OSX上它是一个冒号(:)分隔列表.

要在类路径中包含JAR,您必须运行以下命令...

java -cp .:myjar.jar MyMainClass

其中myjar.jar是您要引用的JAR文件,MyMainClass是包含public static void main方法的类.