Maven-从JAR加载资源？

Question

I have a feeling I'm missing something critical when it comes to bundling resources in JAR files using Maven. My directory structure is the standard Maven one (ie \\src\\main\\java, \\src\\main\\resources).

When using the IDE I reference the resource files as \\main\\resources\\images\\blah... and it works fine, but when Maven bundles the JAR file it puts the paths relative to the root ("\\images\\blah"), so none of the paths are correct.

My question is two-fold really, the first being am I missing something obvious? The second being what's the best way to handle this issue? I know I could just replace all the paths when I go to bundle everything for deployment, or surround all the paths in try/catch blocks, or even change the maven output directory, but I feel like these are in-elegant and I'm missing something. Thanks in advance.

EDIT: I reference the resource files like this: getClass().getResource("/main/resources/images/lightboardImage.jpg"));

EDIT2: This is obviously now an IDE configuration issue, probably stemming from the fact that I converted an old project into one using Maven. I don't really understand how it is misconfigured though. My folder structure is:

src/main/java
src/main/resources

My classpath has one entry for "src" <classpathentry kind="src" path="src"/>

If I right click on the /main/resources/images/ folder and Use as Source Folder it turns the classpathentry into this <classpathentry excluding="main/resources/images/" kind="src" path="src"/> and creates a new one like this <classpathentry kind="src" path="src/main/resources/images"/> . It also doesn't work.

EDIT3: Okay this is really dumb but I just realized what the issue is. I'm not actually using Maven for local development builds. It's using Eclipse's built in Ant configuration or whatever. Maven is used for the automated deployment builds, hence the issue. Sorry to waste everyone's time.

Answer 1

This should work from IDE and from JAR.

getClass().getResource("images/lightboardImage.jpg");

Files from src/main/resources are copied to target/classes .

During runtime, all resources should be visible from classpath as images/lightboardImage.jpg . This works from IDE for me. If not, check your IDE configuration as said @juanluisrp.

Java executed from my IDE looks like this:

java  -classpath (...) /home/.../target/classes (...)

So, the runtime classpath is configured to target/classes directory.

Answer 2

During the lifecycle of Maven, resources are copied to target/classes . When the JAR is assembled target/classes content goes to the JAR root. So, if you want to load a resource that is in the JAR you can use

getClass().getResource("/images/lightboardImage.jpg"));

From the IDE it should work with the same path unless you don't have classpath properly configured. If you are using Eclipse check that src/main/resources is marked as source folder.

Answer 3

I think the problem here is that you need to set your IDE to point to src/main/resources as part of the classpath. Then you can use getClass().getResource("images\\lightboardImage") for both running under maven and from your IDE.

For example, in Eclipse you would do this by right-clicking on src/main/resources in the Project Explorer and clicking "Build Path" -> "Use as Source Folder"