如何获得同级Maven项目的jar工件的路径？

Question

I have a java console based application that is created as a jar file and is run using:

java -jar commandlineapp.jar

The application is built using maven. I have a junit test project that is also a maven project, ie

parent
+- pom.xml
+- commandlineapp
|  +-pom.xml
+- commandlineapp_test
   +pom.xml

The test project has a dependency on the commandlineapp to ensure that the app is built prior to running the test.

The test project has some junit unit tests that execute the commmandlineapp using ProcessBuilder . Eg

String jarfile = 
 "C:\\Users\\me\\.m2\\repository\\my\\org\\commandlineapp\\0.0.1-SNAPSHOT\\commandlineapp-.0.1-SNAPSHOT.jar";

ProcessBuilder pb = new ProcessBuilder("java", "-jar", jarFile);

At the moment, you can see that I have a hard-coded path to the commandlineapp jar file.

Question: is there some meta data that I can use to look up jar path for the sibling project? Ideally, I would still like to be able to run the unit tests from eclipse in addition to running them from maven.

Answer 1

One way is to use the maven dependency plugin in the test project to copy the commandlineapp (and its dependencies) to the test project:

     <plugin>
        <artifactId>maven-dependency-plugin</artifactId>
        <executions>
           <execution>
              <phase>process-test-resources</phase>
              <goals>
                 <goal>unpack-dependencies</goal>
              </goals>
              <configuration>
                 <outputDirectory>${project.build.directory}/lib</outputDirectory>
              </configuration>
           </execution>
        </executions>
     </plugin>

Then from within the test project, you can get access to the target folder:

File testClassesFolder = 
   new File(CommandLineAppTest.class.getClassLoader().getResource(".").getFile());

We need to create a string with the class path. The classpath

String classPath = testClassesFolder.getParent() + File.separator + "lib";

Then pass this to ProcessBuilder:

ProcessBuilder pb = 
  new ProcessBuilder(
     javaExecutablePath, "-cp", classPath, "my.org.CommandLineApp"
  );