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());
BufferredReader reader = new BufferedReader(new FileReader(file));

//Read the file

并且在运行时工作正常Eclipse，但是如果我将它导出到jar，那么运行它就会出现IllegalArgumentException：

and it works fine when running it in Eclipse, but if I export it to a jar the 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

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());

然后它正好相反（它适用于jar而不是eclipse）。

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

我正在使用Eclipse，我的文件夹在一个类文件夹中。

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文件只要求 ClassLoader 返回通过 InputStream 获取资源=http://docs.oracle.com/javase/7/docs/api/java/lang/Class.html#getResourceAsStream%28java.lang.String%29 =noreferrer> 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，无论 file.txt 资源是否在 classes / 目录或 jar 内。

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不是分层的因为jar文件中资源的URI看起来像这样： file：/example.jar！/file.txt 。您无法读取 jar （一个 zip 文件）中的条目，就像它是一个普通的文件。

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.

以下答案解释了这一点：

This is explained well by the answers to:

• 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不是分层的

• How do I read a resource file from a Java jar file?
• Java Jar file: use resource errors: URI is not hierarchical

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