找不到主类中的文件编译的蚂蚁 [英] Cannot find Main Class in File Compiled With Ant

问题描述

我编译在Eclipse运行我的程序，一切工作正常，但是当我使用Ant打包并运行它，我得到这个错误：

I compile and run my program in Eclipse and everything works fine, but when I package it with Ant and run it, I get this error:

Exception in thread "main" java.lang.NoClassDefFoundError: org/supercsv/io/ICsvB
eanReader
Caused by: java.lang.ClassNotFoundException: org.supercsv.io.ICsvBeanReader
        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)
Could not find the main class: jab.jm.main.Test. Program will exit.

请注意，这是一个的运行的错误，而不是一个的编译器错误的使用Ant。

Note that this is a runtime error and not a compiler error with Ant.

我已经建立了这个项目在过去与0的问题，现在的它突然对我的行为，当我添加第二个包到我的lib文件夹？

I've built this project in the past with 0 issues and now it suddenly acts up on me when I add a second package to my lib folder?

下面是引用构建文件：

<?xml version="1.0" ?>

<project name="ServerJar" default="dist" basedir=".">
 <description>
  Builds client files into .jar
 </description>
 <!-- [build variables] -->
 <property name="src" location="src" />
 <property name="build" location="build" />
 <property name="dist" location="dist" />
 <property name="lib" location="lib" />
 <!-- [path to packages] -->
 <path id="master-classpath">
     <fileset dir="${lib}">
         <include name="*.jar"/>
     </fileset>
 </path>


 <target name="init">
  <!-- makes time stamp to be used in jar name -->
  <tstamp />
  <!-- creates build directory structure -->
  <mkdir dir="${build}" />
 </target>

 <target name="compile" depends="init" description="Compiles the source">
  <!-- compiles the java code from ${src} into ${build} -->
  <!-- <javac srcdir="${src}" destdir="${build}" /> -->
  <javac destdir= "${build}">
      <src path="${src}"/>
      <classpath refid="master-classpath"/>
  </javac>
 </target>

 <target name="dist" depends="compile" description="Generates distributable">
  <!-- creates the distribution directory -->
  <mkdir dir="${dist}/lib" />

  <!-- puts everything in ${build} into the jar file -->
  <jar jarfile="${dist}/lib/CC-${DSTAMP}.jar" basedir="${build}">
   <manifest>
    <attribute name="Main-Class" value="jab.jm.main.Test" />
   </manifest>
  </jar>

  <!-- makes a jar file for quick test execution -->
  <jar jarfile="${dist}/lib/CC.jar" basedir="${build}">
   <manifest>
    <attribute name="Main-Class" value="jab.jm.main.Test" />
   </manifest>
  </jar>
 </target>

 <target name="clean" description="Cleans up the extra build files">
  <!-- deletes the ${build} and ${dist} directories -->
  <delete dir="${build}" />
  <delete dir="${dist}" />
 </target>
</project>

在此先感谢您的帮助！

Thanks in advance for the help!

编辑：

下面就是我的主类建筑看起来像（这不是实际的文件，但是这是我根据我的上）。建设是一个Java程序，很奇怪，可能是给蚂蚁的一些问题。在任何建议如何重构呢？我有一大堆试图分成多个部分，这时候的错误。我只是从来没有见过一个像建在此之前（是的，我理解它是如何工作（和它在编译时一样），但蚂蚁可能不喜欢它）。

Here's what the construction for my main class looks like (this is not the actual file, but this is what I based mine on). The construction is very odd for a java program and might be giving Ant some issues. Any recommendations on how to reconstruct this? I got a bunch of errors when trying to separate this into multiple parts. I've just never seen a construction like this before (yes, I understand HOW it works (and it does when compiled), but Ant might not like it).

import java.io.FileReader;
import java.io.IOException;

import org.supercsv.cellprocessor.Optional;
import org.supercsv.cellprocessor.ParseDate;
import org.supercsv.cellprocessor.ParseInt;
import org.supercsv.cellprocessor.constraint.StrMinMax;
import org.supercsv.cellprocessor.constraint.Unique;
import org.supercsv.cellprocessor.ift.CellProcessor;
import org.supercsv.io.CsvBeanReader;
import org.supercsv.io.ICsvBeanReader;
import org.supercsv.prefs.CsvPreference;

class ReadingObjects {
    static final CellProcessor[] userProcessors = new CellProcessor[] {
        new Unique(new StrMinMax(5, 20)),
        new StrMinMax(8, 35),
        new ParseDate("dd/MM/yyyy"),
        new Optional(new ParseInt()),
        null
    };

    public static void main(String[] args) throws Exception {
        ICsvBeanReader inFile = new CsvBeanReader(new FileReader("foo.csv"), CsvPreference.EXCEL_PREFERENCE);
        try {
          final String[] header = inFile.getCSVHeader(true);
          UserBean user;
          while( (user = inFile.read(UserBean.class, header, userProcessors)) != null) {
            System.out.println(user.getZip());
          }
        } finally {
          inFile.close();
        }
   }
}

public class UserBean {
    String username, password, town;
    Date date;
    int zip;

    public Date getDate() {
        return date;
    }
    public String getPassword() {
        return password;
    }
    public String getTown() {
        return town;
    }
    public String getUsername() {
        return username;
    }
    public int getZip() {
        return zip;
    }
    public void setDate(final Date date) {
        this.date = date;
    }
    public void setPassword(final String password) {
        this.password = password;
    }

    public void setTown(final String town) {
        this.town = town;
    }
    public void setUsername(final String username) {
        this.username = username;
    }
    public void setZip(final int zip) {
        this.zip = zip;
    }
}

注意类的名字实际上是如何的UserBean，它包含持有的主要方法中它命名ReadingObjects一个非公共类。

Notice how the class's name is actually UserBean and it contains a non-public class named ReadingObjects within it that holds the main method.

推荐答案

看起来运行时类路径中缺少包含类的 org.supercsv.io.ICsvBeanReader 罐子。

Looks like your runtime classpath is missing the jar containing the class org.supercsv.io.ICsvBeanReader.

的疑难杂症的是，调用一个可执行的JAR，当你不能从命令行设置类路径。你必须在清单设置如下：

The gotcha is that you cannot set the classpath from the command-line when calling an executable jar. You have to set it within the manifest as follows:

<target name="dist" depends="compile" description="Generates distributable">
    <!-- creates the distribution directory -->
    <mkdir dir="${dist}/lib" />

    <!-- Remove manifest. This jar will end up on the classpath of CC.jar -->
    <jar jarfile="${dist}/lib/CC-${DSTAMP}.jar" basedir="${build}"/>

    <!-- Fancy task that takes the pain out creating properly formatted manifest value -->
    <manifestclasspath property="mf.classpath" jarfile="${dist}/lib/CC.jar">
        <classpath>
            <fileset dir="${dist}/lib" includes="*.jar"/>
        </classpath><!--end tag-->
    </manifestclasspath>

    <!-- This is the executable jar -->
    <jar jarfile="${dist}/lib/CC.jar" basedir="${build}">
        <manifest>
            <attribute name="Main-Class" value="jab.jm.main.Test"/>
            <attribute name="Class-Path" value="${mf.classpath}"/> 
        </manifest>
    </jar>

</target>

这个方法可以让你运行jar如下：

This approach will allow you to run the jar as follows:

java -jar CC.jar

如果没有，你必须运行jar如下额外的清单条目：

Without the extra manifest entry you have to run the jar as follows:

java -cp CC.jar:CC-DSTAMPVALUE.jar jab.jm.main.Test

注意

只有CC.jar是可执行的，需要特殊的清单。使用这种模式意味着未来更多的罐，放置到lib目录下，会自动包含在运行时类路径。 （用于开源依赖样的log4j）

Note

Only the CC.jar is executable and needs the special manifest. Using this pattern means future additional jars, placed into the lib directory, will be automatically included in the run-time classpath. (Useful for open source dependencies like log4j)

显然，在运行时CC.jar，你会得到一个类似的错误，如果jar文件都没有present： - ）

Obviously, when running the CC.jar you'll get a similar error if the jar files are not present :-)

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