Classpath选项适用于javac但不适用于java（Windows） [英] Classpath option works for javac but not for java (Windows)

问题描述

感谢您的阅读，

通常使用C＃后，我昨天尝试编写一些java代码来处理XML文件。我没有使用IDE或任何东西，只有Notepad ++，SDK和很多Google：）

after usually working with C# I tried writing some java code yesterday to process an XML file. I didn't use an IDE or anything, just Notepad++, SDK and a lot of Google :)

我需要包含一些我发现的jar文件，需要将类路径设置为命令行参数以查找jar文件。这很有效：

I needed to include some jar files for which I found out, that one needs to set the classpath as a command line parameter to find the jar file. That worked well:

javac -cp "./metadata-extractor-2.9.1.jar;./xmpcore-5.1.2.jar" DescribeIt.java

虽然在使用java.exe运行它时使用了相同的语法运气不佳：

Although using the same syntax when running it with java.exe I had less luck:

java DescribeIt -cp "./metadata-extractor-2.9.1.jar;./xmpcore-5.1.2.jar" 

导致

Exception in thread "main" java.lang.NoClassDefFoundError: com/drewimaging/ImageMetadataReader at DescribeIt.main(DescribeIt.java:53)
Caused by: java.lang.ClassNotFoundException: com.drew.imaging.ImageMetadataReader
        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)
        ... 1 more

当我解压缩jar文件时，它完全正常，但我想这不是jar文件的使用方式。

When I unzip the jar files, it works perfectly fine, but I guess that's not the way jar files are supposed to be used.

可以在这里找到代码和构建批处理文件

Code and build batch file can be found here

非常感谢，

Flo

推荐答案

哎哟!问题是参数的顺序（并添加当前目录）：

Ouch! The problem was the order of parameters (and adding the current directory):

java -cp "metadata-extractor-2.9.1.jar;xmpcore-5.1.2.jar;." DescribeIt 

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