[英]Java Classpath Problems
I've compiled and I am now trying to run this program from the terminal in OSX and Fendora using the following command from within the ie directory: 我已经编译了,现在我正尝试在ie目录中使用以下命令从OSX和Fendora中的终端运行此程序:
java ie.moguntia.webcrawler.Psucker http://www.wikipedia.org test
However I get the following error: 但是我收到以下错误:
Exception in thread "main" java.lang.NoClassDefFoundError: ie/moguntia/webcrawler/Psucker
Caused by: java.lang.ClassNotFoundException: ie.moguntia.webcrawler.Psucker
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
I haven't ran applications that used packages from the command line before so I am therefore unable to figure out the error. 我之前从未运行过使用命令行中的软件包的应用程序,因此无法确定错误。
I have attempted to set the classpath using export CLASSPATH=.
我试图使用
export CLASSPATH=.
设置类路径export CLASSPATH=.
so that the current directory would be added to the classpath. 这样就可以将当前目录添加到类路径中。
The directory structure is as follows: 目录结构如下:
ie/moguntia/webcrawler/
Depending on where your compiled classes are located, you need to include this location in the java command, eg if they are in the classes
directory: 根据编译类的位置,您需要在java命令中包括此位置,例如,如果它们位于
classes
目录中:
java -cp classes ie.moguntia.webcrawler.PSucker http://www.wikipedia.org test
or if they are in the current directory: 或如果它们在当前目录中:
java -cp . ie.moguntia.webcrawler.PSucker http://www.wikipedia.org test
or just 要不就
java ie.moguntia.webcrawler.PSucker http://www.wikipedia.org test
Here's how I was able to run this (unzip, cd to directory, compile, find classes, run): 这是我运行该文件的方法(将文件解压缩,cd到目录,编译,查找类,运行):
(13:55:52) ~/Desktop/temp → ll
total 32
-rw-r--r--@ 1 Nils.Winkler staff 14K 12 Mär 13:41 multiweb.zip
(13:56:01) ~/Desktop/temp → unzip multiweb.zip -d multiweb
Archive: multiweb.zip
creating: multiweb/CVS/
creating: multiweb/ie/
creating: multiweb/ie/CVS/
creating: multiweb/ie/moguntia/
creating: multiweb/ie/moguntia/CVS/
creating: multiweb/ie/moguntia/threads/
creating: multiweb/ie/moguntia/threads/CVS/
inflating: multiweb/ie/moguntia/threads/ControllableThread.java
inflating: multiweb/ie/moguntia/threads/MessageReceiver.java
inflating: multiweb/ie/moguntia/threads/ObjectQueue.java
inflating: multiweb/ie/moguntia/threads/Queue.java
inflating: multiweb/ie/moguntia/threads/ThreadController.java
creating: multiweb/ie/moguntia/webcrawler/
creating: multiweb/ie/moguntia/webcrawler/CVS/
inflating: multiweb/ie/moguntia/webcrawler/PSucker.java
inflating: multiweb/ie/moguntia/webcrawler/PSuckerThread.java
inflating: multiweb/ie/moguntia/webcrawler/SaveURL.java
inflating: multiweb/ie/moguntia/webcrawler/URLQueue.java
inflating: multiweb/ie/moguntia/webcrawler/WSDLCrawler.java
inflating: multiweb/ie/moguntia/webcrawler/WSDLCrawlerThread.java
(13:56:08) ~/Desktop/temp → cd multiweb
(13:56:57) ~/Desktop/temp/multiweb → javac ie/moguntia/webcrawler/*.java
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
(13:57:11) ~/Desktop/temp/multiweb → find . -name *.class
./ie/moguntia/threads/ControllableThread.class
./ie/moguntia/threads/MessageReceiver.class
./ie/moguntia/threads/Queue.class
./ie/moguntia/threads/ThreadController.class
./ie/moguntia/webcrawler/PSucker.class
./ie/moguntia/webcrawler/PSuckerThread.class
./ie/moguntia/webcrawler/SaveURL.class
./ie/moguntia/webcrawler/URLQueue.class
./ie/moguntia/webcrawler/WSDLCrawler.class
./ie/moguntia/webcrawler/WSDLCrawlerThread.class
(13:57:18) ~/Desktop/temp/multiweb → java ie.moguntia.webcrawler.PSucker http://www.wikipedia.org test
[0] http://www.wikipedia.org
It should work if you run it from outside the ie directory. 如果您从ie目录外部运行它,它应该可以工作。
Note that relying on the CLASSPATH
environment variable is generally not recommended; 注意,通常不建议依赖
CLASSPATH
环境变量。 instead explicitly put the classpath on hte command line using the -cp
switch 而是使用
-cp
开关将classpath明确地放在hte命令行上
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