为什么GCJ不能从导入的包中找到类? [英] Why doesn't GCJ find the classes from my imported packages?

问题描述

我想将一个小的Java应用程序编译为Windows可执行文件.

I want to compile a small Java application to a Windows executable.

该应用程序非常小，只有一个主类，但是它使用Apache POI.

The application is very small, only a single main class, but it uses Apache POI.

编译时，只要将POI Jar放入类路径参数中，一切都可以正常工作.

When I compile it, everything works fine, as long as I put the POI Jar into the class path argument.

但是，在进行链接时，GCJ无法解析POI包中的类的引用.消息都是这样的:

But when it comes to linking, GCJ cannot resolve the references the classes in the POI package. The messages are all like this:

undefined reference tp 'org::apache::poi:hssf:usermodel:HSSFWorkbook::class$'

要链接我的应用程序我必须做什么?

What do I have to do in order to link my application?

推荐答案

您必须将导入的Jar分别编译到.so库中.确保在编译库时和在编译代码时都在--classpath中提供Jars.

You have to compile the imported Jars into .so libraries separately. Make sure to provide the Jars in the --classpath, both while compiling the libraries as while compiling your code.

一个示例，其中我正在编译GNU加密库:

An example, where I'm compiling the GNU crypto library:

gcj --classpath=source/:libs/gnu-crypto.jar -fjni -c libs/gnu-crypto.jar -o libs/gnu-crypto.o 
gcj -shared -fPIC -o libs/libgnu-crypto.o libs/gnu-crypto.o -o libs/libgnu-crypto.so 

最后，通过参考库路径的shell脚本执行可执行文件.例如:

Finally, execute your executable through a shell script referencing the library path. For example:

#!/bin/sh
export LD_LIBRARY_PATH=./libs/:$LD_LIBRARY_PATH
exec ./MyJavaApp $*

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