控制 Tomcat 5 上 WEB-INF/lib 中 jar 的类路径顺序？
我有一个在 Tomcat 5.0 中运行的旧版 Web 应用程序。
此 Web 应用程序在 WEB-INF/lib 中有两个 jar，例如 Foo-2.0.jar 和 Bar-2.0.jar。 Bar-2.0.jar 实际上包含一个 Foo-1.0.jar 。 Bar也是一个死项目，意味着没有升级，没有源代码，但对应用程序仍然很重要。
该应用程序的最新版本需要 Foo-2.0.jar 来实现其他一些功能。类路径中同时存在 Foo-1.0.jar 和 Foo-2.0.jar 会产生冲突，特别是 ClassDefNotFound 类型的错误，其中后来在2.0中添加的类在1.0中找不到，等等。
在Eclipse中，简单的解决方案是右键单击您的项目，单击属性> > Java 构建路径 > 订购和导出并将 Foo-2.0.jar 移至 Bar-2.0.jar 上方，以便首先解决该问题。
如何在 Tomcat 的 WEB-INF/lib 中完成此类 jar 的类路径排序？
I have a legacy web app running in Tomcat 5.0.
This web app has two jars in WEB-INF/lib, let's say Foo-2.0.jar and Bar-2.0.jar. Bar-2.0.jar actually includes a Foo-1.0.jar inside of it. Bar is also a dead project, meaning no upgrading, no source, but still important to the application.
The latest release of this application requires Foo-2.0.jar for some other stuff. Having both Foo-1.0.jar and Foo-2.0.jar in the classpath creates a conflict, specifically a ClassDefNotFound type of error, where a class that was later added in 2.0 cannot be found in 1.0, etc.
In Eclipse, the simple solution is to right click on your Project, click Properties > Java Built Path > Order and Export and to move Foo-2.0.jar above Bar-2.0.jar so it's resolved first.
How does one accomplish this type of classpath ordering for jars in WEB-INF/lib in Tomcat?
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Tomcat 5 的 webapp 类加载优先级大致如下：首先是 bootstrap/system（
JRE/lib，然后是 Tomcat 的内部类），然后是 webapp 库（首先是WEB-INF/classes，然后是WEB-INF/ lib），然后是公共库（首先是Tomcat/common，然后是Tomcat/lib），最后是 web 应用程序共享库（Tomcat/shared ）。因此，要在
Bar-2.0.jar之前加载Foo-2.0.jar，最好将Bar- 2.0.jar从WEB-INF/lib到Tomcat/common或Tomcat/shared。JAR 不是按照其名称的字母顺序加载的。至少，没有规范这么说。重命名它们来更改文件名的字母顺序是没有意义的。
Tomcat 5's classloading precedence for webapps is roughly as follows: first the bootstrap/system (
JRE/lib, then Tomcat's internal classes), then the webapp libraries (firstWEB-INF/classes, thenWEB-INF/lib), then the common libraries (firstTomcat/common, thenTomcat/lib) and finally the webapp-shared libraries (Tomcat/shared).So to get
Foo-2.0.jarloaded beforeBar-2.0.jar, best what you can do is to moveBar-2.0.jarfromWEB-INF/libtoTomcat/commonorTomcat/shared.The JAR's aren't loaded in alphabetic order of their name. At least, there's no spec which says that. Renaming them to change the alphabetical filename order makes no sense.
从 Bar-2.0.jar 中剥离 Foo-1.0.jar。事实上，开发（需要修改开发环境）和部署都是麻烦。
Strip Foo-1.0.jar out of Bar-2.0.jar. As it is, it's just trouble waiting to happen both for development(need to fudge the dev. environments) and for deployment.
将 Foo-1.0.jar 放入 $CATALINE_HOME/common/endorsed （或在 Foo-2.0.jar 之后加载的任何其他位置）。
Put Foo-1.0.jar to $CATALINE_HOME/common/endorsed (or any other place where it will be loaded after Foo-2.0.jar).
您不需要，因为 Tomcat 中不提供此功能。如果类路径中同时需要 Foo-1.0.jar 和 Foo-2.0.jar，则需要进行一些主要的类路径重组。
如果 Bar-2.0 可以与 Foo-2.0 一起工作，那么最好的办法就是自己重建 Bar-2.0，而不在其中包含 Foo-1.0.jar。
You don't, as this feature isn't available in Tomcat. If both Foo-1.0.jar and Foo-2.0.jar are needed in the classpath at the same time, you will need some major classpath reorganization.
If Bar-2.0 can work with Foo-2.0, then the best thing to do would be to rebuild Bar-2.0 yourself without a Foo-1.0.jar inside of it.
可以在 jar 的 mainfest 中设置类路径。 http://java.sun.com/developer/Books/ javaprogramming/JAR/basics/manifest.html
我不能真正保证它会解决问题，但值得一试。
It is possible to set the Class-Path in the mainfest of the jar. http://java.sun.com/developer/Books/javaprogramming/JAR/basics/manifest.html
I can't really promise it will solve the problem, but can be worth a try.
要在 Bar-2.0.jar 之前拥有 Foo-2.0.jar，请使用 Foo-2.0.jar 的内容更新 Bar-2.0.jar（覆盖已包含的 .class）并从 war 中删除 Foo-2.0.jar。
-cp A.jar:B.jar 的效果是，A.jar 的内容就像 B.jar 上的一层。因此，用 A.jar 覆盖 B.jar 的内容会得到相同的效果。
To have Foo-2.0.jar before Bar-2.0.jar, update the Bar-2.0.jar with the content of Foo-2.0.jar (overwrite already contained .class)and delete Foo-2.0.jar from the war.
-cp A.jar:B.jar has the effect, that content of A.jar is like a layer over B.jar. So you get the same effect with overwriting B.jar's content with A.jar's.
这有点 hacky 但可能有效。将 Foo-2.0.jar 的名称更改为按字母顺序位于 Bar-2.0.jar 之前，例如 AFoo-2.0.jar。
This is a bit hacky but might work. Change the name of Foo-2.0.jar to be alphabetically ahead of Bar-2.0.jar, say AFoo-2.0.jar.