Java 如何在eclipse中修改src文件并重新编译、生成jar？

我正在修改一个现有的开源项目

它调用proguard，在项目中它有一个src文件夹

我只需要修改其中的一个类文件，并生成jar文件，在eclipse上是否有任何教程/方法可以这样做

我曾尝试在不使用eclipse的情况下修改类文件（例如文本编辑器）， 然后在eclipse中，选择new project=>use the folder as destination，然后我尝试将其导出为jar。它没有错误，并且出现了一个jar文件，但我就是不能运行它。jar文件工作不正常

那么，请兄弟们帮我一下好吗

下载zip文件

修改proguard\classfile中的ClassConstants.java 改变

public static final String ATTR_StackMapTable                        = "StackMapTable";

到

重新编译，输出一个jar文件

就这些

谢谢你的帮助。真的，我已经试了一整天了，谢谢你的帮助

更新

另外，当我更改代码并生成jar时 it输出

JAR creation failed. See details for additional information.
  classfile [in proguard] is not on its project's build path
  Unable to get package fragment root: proguard/classfile/ClassConstants.java
    classfile [in proguard] is not on its project's build path

为什么呢？谢谢

从项目自述文件

ProGuard, Java class file shrinker, optimizer, obfuscator, and preverifier
==========================================================================

This directory contains a number of alternative ways to build ProGuard:

- build.sh      : a shell script for GNU/Linux
- makefile      : a makefile for GNU/Linux
- build.xml     : an Ant build file for all platforms
- maven/pom.xml : a Maven POM for building the Maven artifacts

- As a final alternative, you can also easily compile the code from the
  command line:

    mkdir classes
    javac -sourcepath src -d classes src/proguard/ProGuard.java
    javac -sourcepath src -d classes src/proguard/gui/ProGuardGUI.java
    javac -sourcepath src -d classes src/proguard/retrace/ReTrace.java

  For the ProGuard Ant task:

    javac -sourcepath src -d classes -classpath lib/ant.jar \
        src/proguard/ant/ProGuardTask.java

  For the ProGuard Gradle task:

    javac -sourcepath src -d classes -classpath ..... \
        src/proguard/gradle/ProGuardTask.java

  For the Java Micro Edition Wireless Tool Kit (JME WTK) obfuscator plug-in:

    javac -sourcepath src -d classes -classpath wtklib/kenv.zip \
        src/proguard/wtk/ProGuardObfuscator.java

Note that you'll have to install Ant and the JME WTK yourself.

Enjoy!

http://proguard.sourceforge.net/

Copyright (c) 2002-2013 Eric Lafortune (eric@graphics.cornell.edu)

---

有没有办法从中构建一个jar？谢谢，我正在使用windows 7，您应该将项目导出为“可运行的JAR文件”。在向导的后续步骤中，您将被要求指定启动配置（程序的入口点或使用

main

方法的类）。

谢谢，但我在启动配置中没有看到任何内容，因此无法继续？如果是，则您必须右键单击使用main方法的类并选择“运行方式…”->“Java应用程序”。之后，相应的启动配置将显示在列表中。

ProGuard, Java class file shrinker, optimizer, obfuscator, and preverifier
==========================================================================

This directory contains a number of alternative ways to build ProGuard:

- build.sh      : a shell script for GNU/Linux
- makefile      : a makefile for GNU/Linux
- build.xml     : an Ant build file for all platforms
- maven/pom.xml : a Maven POM for building the Maven artifacts

- As a final alternative, you can also easily compile the code from the
  command line:

    mkdir classes
    javac -sourcepath src -d classes src/proguard/ProGuard.java
    javac -sourcepath src -d classes src/proguard/gui/ProGuardGUI.java
    javac -sourcepath src -d classes src/proguard/retrace/ReTrace.java

  For the ProGuard Ant task:

    javac -sourcepath src -d classes -classpath lib/ant.jar \
        src/proguard/ant/ProGuardTask.java

  For the ProGuard Gradle task:

    javac -sourcepath src -d classes -classpath ..... \
        src/proguard/gradle/ProGuardTask.java

  For the Java Micro Edition Wireless Tool Kit (JME WTK) obfuscator plug-in:

    javac -sourcepath src -d classes -classpath wtklib/kenv.zip \
        src/proguard/wtk/ProGuardObfuscator.java

Note that you'll have to install Ant and the JME WTK yourself.

Enjoy!

http://proguard.sourceforge.net/

Copyright (c) 2002-2013 Eric Lafortune (eric@graphics.cornell.edu)