将类路径文件名转换为实际文件名 [英] Convert a classpath filename to a real filename
问题描述
如何将类路径上的文件名转换为真实文件名?
How would I convert the name of a file on the classpath to a real filename?
例如,假设目录C :\ workspace \ project #\\ target\\ class
在您的类路径中。在该目录中是一个文件,例如 info.properties
。
For example, let's say the directory "C:\workspace\project\target\classes"
is on your classpath. Within that directory is a file, such as info.properties
.
您如何确定(在运行时) info.properties文件的绝对文件路径,只给出字符串info.properties
?
How would you determine (at runtime) the absolute file path to the info.properties file, given only the string "info.properties"
?
结果就像C:\ workspace \project\target\classes\info.properties
。
为什么这有用?编写单元测试时,您可能希望访问测试资源中捆绑的文件( src / main / resources
),但是正在使用第三方库或其他需要的系统一个真正的文件名,而不是一个相对的类路径引用。
Why is this useful? When writing unit tests, you may want to access files bundled in your test resources (src/main/resources
) but are working with a third-party library or other system that requires a true filename, not a relative classpath reference.
注意:我自己已经回答了这个问题,因为我觉得这是一个有用的技巧,但看起来没有人有曾经问过这个问题。
Note: I've answered this question myself, as I feel it's a useful trick, but it looks like no one has ever asked this question before.
推荐答案
使用ClassLoader.getResource()和URL.getFile()的组合
Use a combination of ClassLoader.getResource() and URL.getFile()
URL url = Thread.currentThread().getContextClassLoader().getResource( resource );
if( url == null ){
throw new RuntimeException( "Cannot find resource on classpath: '" + resource + "'" );
}
String file = url.getFile();
Windows注意事项:在上面的示例中,实际结果将是
Note for Windows: in the example above, the actual result will be
"/C:/workspace/project/target/classes/info.properties"
如果你需要更像Windows的路径(即C:\ workspace \ ...
),使用:
If you need a more Windows-like path (i.e. "C:\workspace\..."
), use:
String nativeFilename = new File(file).getPath();
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