I am using wro4j-maven-plugin (version 1.8.0) for building my web resources:
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<executions>
<execution>
<!-- Serves *only* to filter the wro.xml so it can get an absolute
path for the project -->
<id>copy-resources</id>
<phase>validate</phase>
<goals>
<goal>copy-resources</goal>
</goals>
<configuration>
<outputDirectory>${basedir}/target/wro</outputDirectory>
<resources>
<resource>
<directory>src/main/wro</directory>
<filtering>true</filtering>
</resource>
</resources>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>ro.isdc.wro4j</groupId>
<artifactId>wro4j-maven-plugin</artifactId>
<version>1.8.0</version>
<executions>
<execution>
<phase>generate-resources</phase>
<goals>
<goal>run</goal>
</goals>
</execution>
</executions>
<configuration>
<wroManagerFactory>ro.isdc.wro.maven.plugin.manager.factory.ConfigurableWroManagerFactory</wroManagerFactory>
<cssDestinationFolder>${project.build.directory}/generated-resources/static/css</cssDestinationFolder>
<jsDestinationFolder>${project.build.directory}/generated-resources/static/js</jsDestinationFolder>
<wroFile>${basedir}/src/main/wro/wro.xml</wroFile>
<extraConfigFile>${basedir}/src/main/wro/wro.properties</extraConfigFile>
<contextFolder>${basedir}/src/main/wro</contextFolder>
<ignoreMissingResources>false</ignoreMissingResources>
</configuration>
<dependencies>
<dependency>
<groupId>org.webjars</groupId>
<artifactId>jquery</artifactId>
<version>2.2.3</version>
</dependency>
<dependency>
<groupId>org.webjars</groupId>
<artifactId>angularjs</artifactId>
<version>1.5.5</version>
</dependency>
<dependency>
<groupId>org.webjars</groupId>
<artifactId>bootstrap</artifactId>
<version>3.3.6</version>
</dependency>
<dependency>
<groupId>org.webjars</groupId>
<artifactId>angular-ui-bootstrap</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>org.webjars</groupId>
<artifactId>angular-ui-router</artifactId>
<version>0.2.18</version>
</dependency>
<dependency>
<groupId>org.webjars.bower</groupId>
<artifactId>fontawesome</artifactId>
<version>4.5.0</version>
</dependency>
<dependency>
<groupId>org.webjars.bower</groupId>
<artifactId>angular-resource</artifactId>
<version>1.5.5</version>
</dependency>
<dependency>
<groupId>org.webjars</groupId>
<artifactId>URI.js</artifactId>
<version>1.14.1</version>
</dependency>
</dependencies>
</plugin>
</plugins>
My wro.xml looks like this:
<groups xmlns="http://www.isdc.ro/wro">
<group name="angular-bootstrap">
<css>webjar:bootstrap/3.3.6/less/bootstrap.less</css>
<css>webjar:fontawesome/4.5.0/less/font-awesome.less</css>
<css>file:${project.basedir}/src/main/wro/main.less</css>
<js>webjar:jquery/2.2.3/jquery.js</js>
<js>webjar:bootstrap/3.3.6/js/bootstrap.js</js>
<js>webjar:angularjs/1.5.5/angular.js</js>
<js>webjar:angular-resource/1.5.5/angular-resource.js</js>
<js>webjar:angular-ui-router/0.2.18/angular-ui-router.js</js>
<js>webjar:angular-ui-bootstrap/1.3.2/ui-bootstrap.js</js>
<js>webjar:angular-ui-bootstrap/1.3.2/ui-bootstrap-tpls.js</js>
<js>webjar:URI.js/1.14.1/URI.js</js>
</group></groups>
Here is my wro.properties file:
preProcessors=lessCssImport postProcessors=less4j,jsMin debug=true
When I run mvn clean install I got the following error:
[INFO] Executing the mojo:
[INFO] Wro4j Model path: D:\Entwicklungsumgebung\workspace.services\rs\src\main\wro\wro.xml
[INFO] targetGroups: null
[INFO] minimize: true
[INFO] ignoreMissingResources: false
[INFO] parallelProcessing: false
[INFO] buildDirectory: D:\Entwicklungsumgebung\workspace.services\rs\target
[INFO] destinationFolder: D:\Entwicklungsumgebung\workspace.services\rs\target
[INFO] jsDestinationFolder: D:\Entwicklungsumgebung\workspace.services\rs\target\generated-resources\static\js
[INFO] cssDestinationFolder: D:\Entwicklungsumgebung\workspace.services\rs\target\generated-resources\static\css
[INFO] The following groups will be processed: [angular-bootstrap]
[INFO] folder: D:\Entwicklungsumgebung\workspace.services\rs\target\generated-resources\static\css
[INFO] processing group: angular-bootstrap.css
[ERROR] Cannot ignore missing resource: ro.isdc.wro.model.resource.Resource@77d680e6[CSS,file:${project.basedir}/src/main/wro/main.less,true]
[ERROR] Exception while merging resources: ${project.basedir}\src\main\wro\main.less (Das System kann den angegebenen Pfad nicht finden)
[ERROR] Exception occured while processing: ro.isdc.wro.WroRuntimeException: Exception while merging resources: ${project.basedir}\src\main\wro\main.less (Das System kann den angegebenen Pfad nicht finden), class: ro.isdc.wro.WroRuntimeException,caused by: java.io.**FileNotFoundException**
ro.isdc.wro.WroRuntimeException: Exception while merging resources: ${project.basedir}\src\main\wro\main.less (Das System kann den angegebenen Pfad nicht finden)
The ${project.basedir} placeholder is not replaced by maven, as result the wro4j searches literally for the resource with the following path "${project.basedir}/src/main/wro/main.less" which is obviously invalid.
Either user servlet context relative resources, classpath resources, webjar resources or absolute path resources.