用jwrapper构建的jar无法正常工作 [英] jar built with jwrapper doesn't work

问题描述

jwrapper会以某种方式操纵应用程序jar，并导致jar无法运行:在运行时，它将引发无法将MyClass强制转换为MyClass"类型错误.我认为，这是由于重新评估创建类加载器的代码导致的，从而导致类MyClass的多个实例被加载.

jwrapper manipulates application jars somehow, and is resulting in a non-functioning jar: at runtime it throws a "MyClass cannot be cast to MyClass" type error. I believe this is caused by re-evaluating code that creates a class loader, leading to multiple instances of class MyClass being loaded.

除了使用pack200之外，jwrapper文档没有描述对jar所做的更改.我已经单独测试了pack200，它不会导致此问题.

The jwrapper docs don't describe the changes made to the jar, except for the use of pack200. I've tested pack200 in isolation, and it does not cause this problem.

我还通过将jwrapper传递给"java -jar"来测试由jwrapper构建的jar，而无需使用wrapper可执行文件.因此，这不是jvm转换，也不是包装程序正在执行的任何其他操作:jar本身已损坏.

I've also tested the jar built by jwrapper without using the wrapper executable, by passing it to "java -jar". So it's not jvm transmuting, or anything else that the wrapper is doing: the jar itself is broken.

更新:

jwrapper允许跳过pack200，但是安装文件很大.由于pack200可以在独立运行时运行，因此，如果可以通过某种方式告诉jwrapper文件已经打包，则可以解决此问题.使用< Pack200Exceptions>没有帮助，因为那时它不知道文件已打包.

jwrapper allows skipping pack200, but then the install file is huge. Since pack200 works when run standalone, I could work around this if there were some way to tell jwrapper that the file is already packed. Using <Pack200Exceptions> doesn't help, because then it doesn't know the file is packed.

推荐答案

潜在的问题是jwrapper将pack200选项"modification_time"设置为"latest"，这会更改所有类文件的修改时间.在运行时，这会导致clojure编译器尝试从源代码重新编译类.

The underlying problem is that jwrapper sets the pack200 option "modification_time" to "latest", which changes the modification times of all the class files. At run-time this causes the clojure compiler to attempt to recompile the classes from source.

一种解决方法是在打包之前从jar中删除.clj文件，以防止编译器运行. lein的:omit-source"选项在这里是不够的，因为它从任何依赖项保留在.clj文件中.相反，您必须在:uberjar-exclusions中使用模式，例如

A work-around is to remove the .clj files from the jar prior to packaging, preventing the compiler from running. The lein ":omit-source" option is not sufficient here, because it leaves in .clj files from any dependencies. Instead you must use a pattern in :uberjar-exclusions, e.g.

:uberjar排除项[#.(clj | java)"]

:uberjar-exclusions [#".(clj|java)"]

如此处所述:

https://github.com/technomancy/leiningen/issues/1357

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