从 jar 中读取资源文件 [英] Reading a resource file from within jar

问题描述

我想从我的 jar 中读取资源，如下所示:

I would like to read a resource from within my jar like so:

File file;
file = new File(getClass().getResource("/file.txt").toURI());
BufferedReader reader = new BufferedReader(new FileReader(file));

//Read the file

并且在 Eclipse 中运行它时工作正常，但是如果我将其导出到 jar 中，然后运行它，则会出现 IllegalArgumentException:

and it works fine when running it in Eclipse, but if I export it to a jar, and then run it, there is an IllegalArgumentException:

Exception in thread "Thread-2"
java.lang.IllegalArgumentException: URI is not hierarchical

我真的不知道为什么但是通过一些测试我发现如果我改变了

and I really don't know why but with some testing I found if I change

file = new File(getClass().getResource("/file.txt").toURI());

到

file = new File(getClass().getResource("/folder/file.txt").toURI());

然后它的工作相反(它在 jar 中工作，但在 eclipse 中不工作).

then it works the opposite (it works in jar but not eclipse).

我正在使用 Eclipse，我的文件所在的文件夹位于类文件夹中.

I'm using Eclipse and the folder with my file is in a class folder.

推荐答案

而不是尝试将资源作为 File 只需询问 ClassLoader 返回一个 InputStream 而不是通过 getResourceAsStream:

Rather than trying to address the resource as a File just ask the ClassLoader to return an InputStream for the resource instead via getResourceAsStream:

InputStream in = getClass().getResourceAsStream("/file.txt"); 
BufferedReader reader = new BufferedReader(new InputStreamReader(in));

只要 file.txt 资源在类路径上可用，那么无论 file.txt 资源是否在 file.txt 资源中，这种方法都会以相同的方式工作code>classes/ 目录或 jar.

As long as the file.txt resource is available on the classpath then this approach will work the same way regardless of whether the file.txt resource is in a classes/ directory or inside a jar.

URI 不是分层的 发生是因为 jar 文件中资源的 URI 看起来像这样:file:/example.jar!/file.txt.您无法像普通的旧 文件.

The URI is not hierarchical occurs because the URI for a resource within a jar file is going to look something like this: file:/example.jar!/file.txt. You cannot read the entries within a jar (a zip file) like it was a plain old File.

以下回答很好地解释了这一点:

This is explained well by the answers to:

• 如何如何从 Java jar 文件中读取资源文件?
• Java Jar 文件:使用资源错误:URI没有层次结构

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