可执行jar文件错误 [英] Executable jar file error

问题描述

嘿，我正在开发java应用程序。
我完成了编码部分，但是当我运行它时，我在线程主java.lang.noclassdeffounderror 中收到了异常。我通过互联网搜索了这个，但找不到合适的答案。

让我解释一下我在从eclipse导出java程序到可执行jar文件之前所做的事情： / p>

• 我在库中添加了一些jar文件，因此我的程序可以连接第三方程序。它从一个名为SSC的自定义Jre运行，
  在第三方程序（SunSystems）位置文件夹中获得位置。




• 我编写了运行该程序所需的java代码。




• 然后我跑了该项目，当我从eclipse运行时效果很好。




• 我点击了项目的名称然后点击了导出。我选择Runnable jar文件并将所需的文件复制到子文件夹中，接下来
  生成jar文件。我从启动
  配置中选择了正确的类。然后点击完成。

当我通过输入 java -jar从cmd运行jar文件时ssc.jar 它给了我这个错误：

 线程主java.lang.noclassdeffounderror $中的异常b $ b  

以及带标记的其他一些行。

我该怎么做才能解决这个问题？

有些文件说我需要添加类路径来编程，或编辑清单文件等。我无法弄清楚如何。

感谢您的帮助。谢谢

（编辑）演示包下的SSC.java类。当我从日食运行时它起作用：

  package demo; 
 
 import java.io.BufferedReader; 
 import java.io.BufferedWriter; 
 import java.io.File; 
 import java.io.FileReader; 
 import java.io.FileWriter; 
 import com.systemsunion.ssc.client。*; 
 
公共类SSC {
 
 static String HOST =localhost; 
 static int Port = 8080; 
 
 public static void main（String [] args）{
 try 
 {
 SecurityProvider secman = new SecurityProvider（HOST，true）; 
 String voucher = secman.Authenticate（PKP，）。toString（）; 
 String sInputPayload =; 
 String path =C：/ SSC temp / temp.txt; 
 BufferedReader reader = new BufferedReader（new FileReader（path））; 
 BufferedWriter writer = new BufferedWriter（new FileWriter（new File（C：/ SSC temp / temp-result.txt）））; 
 String line =; 
 while（（line = reader.readLine（））！= null）
 {
 sInputPayload = sInputPayload + line; 
} 
尝试
 {
 SoapComponent ssc = new SoapComponent（HOST，Port）; 
 ssc.authenticate（凭证）; 
 String result = ssc.execute（Journal，Import，sInputPayload）; 
 writer.write（result）; 
 writer.newLine（）; 
 writer.close（）; 
} 
 catch（exception ex）
 {
 ex.printStackTrace（）; 
} 
} 
 catch（exception ex）
 {
 ex.printStackTrace（）; 
} 
} 
} 
  

运行jar时出错来自cmd的文件：

 线程main中的异常java.lang.NoClassDefFoundError：com / systemsunion / ssc / 
 
 client / SoapComponent 
 at java.lang.Class.getDeclaredMethods0（Native Method）
 at java.lang.Class.privateGetDeclaredMethods（Unknown Source）
 at java.lang.Class。 getMethod0（未知来源）
 at java.lang.Class.getMethod（Unknown Source）
 at sun.launcher.LauncherHelper.getMainMethod（Unknown Source）
 at sun.launcher.LauncherHelper.checkAndLoadMain（未知来源）
引起：java.lang.ClassNotFoundException：com.systemsunion.ssc.client.SoapCom 
 ponent 
 at java.net.URLClassLoader $ 1.run（Unknown Source）
在java.net.URLClassLoader $ 1.run（未知来源）
 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更多
  

解决方案

问题在于将所需的库复制到生成的JAR旁边的子文件夹。执行此操作时，库将复制到与创建的jar文件相同的文件夹中的子文件夹。当您尝试运行jar文件时，必须将此子文件夹的所有jar添加到类路径中（我不确定通配符是否有效 - 我认为它们将使用Java 7）：

  java -cp sub\jar1.jar; sub \ jar2.jar -jar ssc.jar 
  

为了避免这个问题（必须添加所有jar文件很麻烦），你可以使用以下任何一个：

• 将所需的库提取到生成的JAR


• 将所需的包打包到生成的JAR中

优点是：您的应用程序JAR现在将随内置所有依赖项一起运行，因此它始终有效。 缺点是： JAR内部存在依赖关系（可能导致一个非常大的JAR文件，其中可能只有一小部分是您的实际应用程序）。

编辑：您可能还需要在上面的命令行中添加对项目的引用。有关详细信息，请参阅此答案的评论。

Hey there i am developing java application. I completed coding part but i am recieving exception in thread main java.lang.noclassdeffounderror when i ran it. I have searched this through the internet, and could not find suitable answer.

Let me explain what i have done before exporting java program to the executable jar file from eclipse:

• I added some jar files to my library so my program could connect a 3rd party program. It runs from a custom Jre which is named SSC and got location in 3rd party program's(SunSystems) location folder.

• I wrote the required java code to run the program.

• Then i ran the project, which works perfectly when i run from eclipse.

• I clicked on project's name then clicked Export. I selected Runnable jar file and Copy required libraries into sub-folder next to generated jar file. I picked correct class from launch configuration. Then clicked finish.

When i ran the jar file from cmd by typing java -jar ssc.jar It gives me this error:

exception in thread main java.lang.noclassdeffounderror

and some other lines with tag.

What should i do to fix this?

Some documentations say that i need add classpath to program, or edit manifest file etc. I could not figure out how.

I would appreciate your help. Thanks

(Edit)SSC.java class under the demo package. It works when i run from the eclipse:

package demo;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import com.systemsunion.ssc.client.*;

public class SSC {

    static String HOST="localhost";
    static int Port=8080;

    public static void main(String[] args) {
        try
        {
            SecurityProvider secman= new SecurityProvider(HOST,true);           
            String voucher= secman.Authenticate("PKP","").toString();
            String sInputPayload="";
            String path="C:/SSC temp/temp.txt";
            BufferedReader reader= new BufferedReader(new FileReader(path));
            BufferedWriter writer= new BufferedWriter(new FileWriter(new File("C:/SSC temp/temp-result.txt")));
            String line="";
            while((line = reader.readLine()) != null)
            {
                sInputPayload = sInputPayload + line;
            }
            try
            {
                SoapComponent ssc= new SoapComponent(HOST, Port);
                ssc.authenticate(voucher);
                String result= ssc.execute("Journal", "Import", sInputPayload);
                writer.write(result);
                writer.newLine();
                writer.close();
            }
            catch(Exception ex)
            {
                ex.printStackTrace();
            }
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }
    }
}

Error when i ran the jar file from cmd:

Exception in thread "main" java.lang.NoClassDefFoundError: com/systemsunion/ssc/

    client/SoapComponent
            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: com.systemsunion.ssc.client.SoapCom
    ponent
            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

解决方案

The problem is with "Copy required libraries into a sub-folder next to the generated JAR". When you do this, the libraries are copied to a sub-folder in the same folder as the created jar file. When you attempt to run the jar file, you must add all the jars this sub-folder to the classpath (I'm not sure if wildcards work - I think they will with Java 7):

java -cp sub\jar1.jar;sub\jar2.jar -jar ssc.jar

To avoid this issue (having to add all the jar files is cumbersome), you can use either of these:

• Extract required libraries into generated JAR
• Package required libraries into generated JAR

The advantage is: your application JAR will now travel with all dependencies built-in so it will always work. The disadvantage is: a JAR bloated with the dependencies inside (potentially resulting in a very large JAR file, out of which maybe only a small part is your actual application).

Edit: You may also need to add a reference to your project in the command line above. See comments on this answer for more details.

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