运行jar依赖的java类文件
java.lang.NoClassDefFoundError
我有一个依赖于两个 jar 文件的 java 程序。 我使用命令编译程序：
javac -classpath jar1.jar:jar2.jar myprog.java 它编译成功。
但是当我尝试使用命令运行程序时： java -cp jar1.jar:jar2.jar myprog ，它抛出 java.lang.NoClassDefFoundError 。请帮忙，我哪里错了？
我正在使用 ubuntu 10.04。
实际错误：
Exception in thread "main" java.lang.NoClassDefFoundError: userapps/SelectionTask_classes/SelectionTask
Caused by: java.lang.ClassNotFoundException: userapps.SelectionTask_classes.SelectionTask
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: userapps/SelectionTask_classes/SelectionTask. Program will exit.
其中SelectionTask是我成功编译后生成的类文件。
java.lang.NoClassDefFoundError
I have a java program which is dependant on two jar files.
i compile the program using command :
javac -classpath jar1.jar:jar2.jar myprog.java and it compiles successfully.
But when i try to run the program using command : java -cp jar1.jar:jar2.jar myprog , it is throwing the java.lang.NoClassDefFoundError . please help , where am i wrong ?
i am using ubuntu 10.04.
Actual error :
Exception in thread "main" java.lang.NoClassDefFoundError: userapps/SelectionTask_classes/SelectionTask
Caused by: java.lang.ClassNotFoundException: userapps.SelectionTask_classes.SelectionTask
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: userapps/SelectionTask_classes/SelectionTask. Program will exit.
where SelectionTask is my class file generated after successful compilation.
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（3）
确保当前目录也在类路径中。尝试运行：
如果编译的类文件
myprog.class位于当前目录中。（这假设您的程序不在包中）。
Make sure that the current directory is also in the classpath. Try running with:
if your compiled class file
myprog.classis in the current directory.(This assumes that your program is not in a package).
您需要添加已编译的java程序（*.class）文件所在的目录。如果它位于当前目录中，那么您可以像这样运行它（注意“.”，它表示当前工作目录）：
You need to add directory where your compiled java program (*.class) file is located. If it's in current directory then you could run it like this (notice "." which denotes current working directory):
查看错误，它抱怨无法找到“userapps.SelectionTask_classes.SelectionTask”，这暗示类路径中的最后一个条目未正确指定。现在，假设您指定的 JAR 文件位于以下目录结构中：
./hadoop-0.20.1-core.jar
./lib/hadoopdb.jar
./userapps/SelectionTask_classes/
您将运行：
Look at the error, it's complaining about not being able to find "userapps.SelectionTask_classes.SelectionTask", which hints at the last entry in your classpath not beign specified correctly. Now, assuming that the JAR files you have specified are in the following directory structure:
./hadoop-0.20.1-core.jar
./lib/hadoopdb.jar
./userapps/SelectionTask_classes/
You would run: