Locating resources within a jar package

Question

I have a static class and inside that class images are loaded into BufferedImage objects like so:

File groundTopImageFile = new File("src/main/resources/ground - grass top.png");

Now when I create an executable jar out of this using Maven2 everything works, except it doesn't find the image files. I checked the jar, and the image files have all been put in the root of the jar, so I tried using:

File groundTopImageFile = new File("ground - grass top.png");

but no success. Also in this way I can't use the same code within Eclipse anymore. Is there some way to make this work both in the jar and in Eclipse?

This is my Pom.xml file:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.WetWindmill</groupId> <artifactId>Sheepness</artifactId> <name>Sheepness</name> <version>0.0.1-SNAPSHOT</version> <description>Equilibrium reaction visualized with sheep :)</description> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.4</version> <scope>test</scope> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.5.8</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>1.6</source> <target>1.6</target> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <executions> <execution> <id>unpack-dependencies</id> <phase>generate-resources</phase> <goals> <goal>unpack-dependencies</goal> </goals> </execution> </executions> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <configuration> <archive> <manifest> <mainClass>controller.Sheepness</mainClass> <packageName>com.WetWindmill.Sheepness</packageName> </manifest> <manifestEntries> <mode>under development</mode> <url>www.WetWindmill.com/Projects/Sheepness/</url> </manifestEntries> </archive> </configuration> </plugin> </plugins> <resources> <resource> <directory>${basedir}/target/dependency</directory> </resource> <resource> <directory>${basedir}/src/main/resources</directory> </resource> </resources> </build> </project>

Sean Patrick Floyd · Accepted Answer · 2010-10-12 14:39:34Z

Use ImageIO.read(inputStream) and read the InputStream using ClassLoader.getResourceAsStream().

Sample Code:

String resourceName = "my/picfolder/mypic.jpg"; ClassLoader classLoader = Thread.currentThread().getContextClassLoader(); InputStream stream = classLoader.getResourceAsStream(resourceName); BufferedImage bi = ImageIO.read(stream);

Note:

In my code example, my/picfolder is the relative folder hierarchy below src/main/resources.

Boris Pavlović · Accepted Answer · 2010-10-13 07:34:38Z

1

URL imgURL = getClass().getResource("/ground - grass top.png"); if (imgURL != null) { return new ImageIcon(imgURL, "Ground Grass Top"); } else { logger.error("Couldn't find file: " + "ground - grass top.png"); return null; }

edited Oct 13, 2010 at 7:34

answered Oct 12, 2010 at 14:31

Boris Pavlović

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3 Comments

Sean Patrick Floyd Over a year ago

don't use src/main/resources, it won't be in the jar.

Sean Patrick Floyd Over a year ago

"resources" won't be there either. In a maven project, anything directly inside src/main/resources will be copied to the root level of the jar.

Neeme Praks Over a year ago

From the question it seems that the image is at the root of the JAR (default package). Your current code will load it from current package, not from the root/default package. Better add a leading slash to the image name or use getClass().getClassloader().getResource(String) to load the resource without leading slash (similar to the way "seanizer" proposed in his answer).

duffymo · Accepted Answer · 2010-10-12 14:28:50Z

0

Use the class loader getResourceAsStream() method.

answered Oct 12, 2010 at 14:28

duffymo

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Comments

duypt · Accepted Answer · 2011-10-06 06:24:14Z

Instead of using "/./resources/back_img.png", use "resources/back_img.png" with ClassLoader. Here is example :

 String path = "resources/back_img.png"; ClassLoader cl = ImageHandler.class.getClassLoader(); URL imgURL = cl.getResource(path); //URL imgURL = ImageHandler.class.getResource(path); if (imgURL != null) { ImageIcon icon = new ImageIcon(imgURL, description); Image img = icon.getImage(); Image sizedImg = img.getScaledInstance(width, height, Image.SCALE_DEFAULT); return new ImageIcon(sizedImg); } else { System.err.println("Couldn't find file: " + path); return null; }

Quyen Le · Accepted Answer · 2014-07-23 07:33:24Z

You solves my problem,Sean Patrick Floyd. Thank It's seem different between IDEs but, see structure of jar file, we know what relative path. As my case, I used Netbean, my file put in src/my/picfolder/mypic.jpg (It 's src/main/resources/my/picfolder/mypic.jpg with Sean), but when built, extract jar file we 'll see image in my/picfolder/mypic.jpg . So relative path must be my/picfolder/mypic.jpg when we call getResourceAsStream

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