jar里面的NoClassDefFoundError [英] NoClassDefFoundError inside jar

问题描述

我有一个类，它位于一个名为com.toptur.sysTray的包中，它只是加载系统托盘，它不使用任何外部包。我创建一个SysTray对象来安装系统托盘。 Everthing构建良好。我可以从命令行运行应用程序并安装systray。但是，当我尝试从类文件创建一个jar并运行它时，我得到NoClassDefFoundError。

I have a class that that sits in a package called com.toptur.sysTray all it does is load system tray it does not use any external packages. i create a SysTray object to install the system tray. Everthing builds fine. i can run the application from command line and systray gets installed. But when i try to create a jar from the class files and run it i get NoClassDefFoundError.

包及其类文件在我的应用程序不使用ant外部的jar中罐子。只是java提供的类。

Package and its class files are in the jar my application does not use ant external jars. just classes provied by java.

如果从jar中构建一个.exe文件，它会再次开始工作而不会出现任何错误。

And if build a .exe file out of the jar, it starts to work again without any errors.

我如何追踪这个？

  <target name="jar" depends="">
  <jar destfile="build/toptur.jar" > 
    <manifest>
      <attribute name="Built-By" value="Toptur"/>
      <attribute name="Main-Class" value="gotacan"/>
    </manifest>
    <fileset dir="build">
       <include name="**/*.class"/>
    <include name="**/*.png"/>
<exclude name="**/*.jar"/>
  </fileset>
</jar>

我从中创建jar文件使用上述代码的蚂蚁目标。驱动程序不在包中。它位于gotacan.java

i create the jar file from a ant target using above code. driver program is not in a package. its located in gotacan.java

我使用java -jar toptur.jar运行它

I run it using java -jar toptur.jar

程序的其余部分当我尝试使用该软件包时，它只会引发异常。

rest of the program works it only throws exception when i try to use that package.

推荐答案

Class not Found Exception应该提到类的名称它正在寻找。

The Class not Found Exception should mention the name of the class it is looking for.

由于你在类路径上只有jar，它应该在jar中，但事实并非如此。找出原因，可能的原因：

Since you have only the jar on the classpath it should be in the jar, but it isn't. Figure out why, possible reasons:

• 当ant构建软件包时，类文件不在它所属的位置


• 表示包名称的目录结构不是以所有其他类为根的所在的根目录


• 类文件所属的位置不包含在要放入的文件列表中jar by ant。

祝你好运

注意：罐子只是拉链具有态度的文件，因此您可以使用任何zip程序来检查实际存在的文件。

Note: jars are just zip files with an attitude, so you can use any zip-program to check what files are actually in there.

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