如何在Spring中从classpath注入资源？

Question

I want to inject a file from src/main/resources like this:

@Value("classpath:myfile.txt")
private Resource res;

When I run this from eclipse it works fine. But from a standalone folder, the file is not found:

Caused by: java.io.FileNotFoundException: class path resource [myfile.txt] cannot be resolved to absolute file path because it does not reside in the file system: jar:file:/D:/myapp/myapp-1.0.0.jar!/myfile.txt
    at org.springframework.util.ResourceUtils.getFile(ResourceUtils.java:212) ~[spring-core-4.1.4.RELEASE.jar:4.1.4.RELEASE]

How can I tell spring that the file to be injected is actually in the root of the jar, not an absolute path?

Same result if I try to load it programmatically.

res = new ClassPathResource("myfile.txt");

Answer 1

You said this works in eclipse:

@Value("classpath:myfile.txt")
private Resource res;

Now try this in eclipse (notice the * ), if it works, standalone should be ok:

@Value("classpath*:myfile.txt")
private Resource res;

When deploying outside eclipse, make sure myfile.txt is on the classpath; the best location is in the root directory where Java class file packages are located ( com , org )

Answer 2

It turned out the injection itself did work, BUT I accessed the file using res.getFile() which threw the NPE.

When just retrieving the URL and fetching the file explicit with File file = ResourceUtils.getFile(res.getURL().getFile()); it worked as expected.

Though I'm not sure wether this is a bug or works as expected.