How can I write maven build to add resources to classpath?

Question

I am building a jar using maven with simple maven install. If I add a file to src/main/resources it can be found on the classpath but it has a config folder where I want that file to go but moving it inside the config folder makes it disappear from the classpath.

score 88 · Answer 1 · edited Jul 14 '17 at 15:00

A cleaner alternative of putting your config file into a subfolder of src/main/resources would be to enhance your classpath locations. This is extremely easy to do with Maven.

For instance, place your property file in a new folder src/main/config, and add the following to your pom:

 <build>
    <resources>
        <resource>
            <directory>src/main/config</directory>
        </resource>
    </resources>
 </build>

From now, every files files under src/main/config is considered as part of your classpath (note that you can exclude some of them from the final jar if needed: just add in the build section:

    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-jar-plugin</artifactId>
            <configuration>
                <excludes>
                    <exclude>my-config.properties</exclude>
                </excludes>
            </configuration>
        </plugin>
    </plugins>

so that my-config.properties can be found in your classpath when you run your app from your IDE, but will remain external from your jar in your final distribution).

+1 | Have a look at the reference documentation for this feature: http://maven.apache.org/pom.html#Resources — rwitzel, Mar 19 '14 at 10:58
I would take issue with this being "cleaner" but possibly, at least, a useful alternative in cases where the directory structure can't be modified. Following the convention is always cleaner — StormeHawke, Sep 03 '14 at 13:56

score 56 · Accepted Answer · edited May 03 '18 at 13:43

56

If you place anything in src/main/resources directory, then by default it will end up in your final *.jar. If you are referencing it from some other project and it cannot be found on a classpath, then you did one of those two mistakes:

*.jar is not correctly loaded (maybe typo in the path?)
you are not addressing the resource correctly, for instance: /src/main/resources/conf/settings.properties is seen on classpath as classpath:conf/settings.properties

edited May 03 '18 at 13:43

WattsInABox

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answered Jan 30 '12 at 11:57

ŁukaszBachman

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The URL protocol "classpath:" is specific to Spring. – simon Jun 24 '16 at 13:31
Do I need to declare (via Spring @PropertySource for example) the location of the .properties file if it is not in the src/main/resources or, say, in /src/main/resources/conf? By default only src/main/resource files are put on the classpath or in any subdir too? Thanks – Andrey M. Stepanov Nov 24 '18 at 19:13
Do I need to import /src/main/resources/application.properties in the first place (@PropertySource ("application.properties") or the default location does not need to be imported? – Andrey M. Stepanov Nov 24 '18 at 19:17

score 10 · Answer 3 · edited Sep 30 '19 at 15:51

By default maven does not include any files from "src/main/java".

You have two possible way to that.

put all your resource files (different than java files) to "src/main/resources" - this is highly recommended
Add to your pom (resource plugin):

 <resources>
       <resource>
           <directory>src/main/resources</directory>
        </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
  </resources>

How can I write maven build to add resources to classpath?

3 Answers3

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