Building with Maven
Maven 3.0.0 or later is required to build Struts 2
First, let’s review some Maven basics. Maven uses the notion of a build life-cycle to which plugins can attach. Plugins are similar to Ant tasks. When a Maven build is invoked, we specify a point in the life-cycle up to which the build should proceed. The compile phase comes before test , and test comes before package , and package comes before install . Once we have Maven setup, we can invoke the Struts build, and specify which phase the build should use.
Installing
The install phase builds up the project (“package”), and installs any JARs it needs into your local repository, e.g.:
~/.m2/repository
Once installed, the JARs can be used by any other Maven project you build. The install phase is the default phase if none is specified.
To run a basic install, change to the root of the source distribution, and enter
mvn
That’s it! Maven will download any dependencies the build needs; run all unit tests; package up the JARs; then install th e new JARs locally. For your convenience, copies of the JARs can be found in the target directories of each module. For example, after the build, the main JAR can found at
core/target/struts2-core-2.0-SNAPSHOT.jar
Sometimes, licensing restrictions prevent Maven from downloading all the JARs that a build might need. For example, JavaMail and Activation, can only be downloaded from Sun. When this happens, Maven will display a helpful message that explains how to install these JARs manually. After downloading the required JAR, follow the instructions to install it to the your local repository. Once installed, the JAR is available to all your Maven builds, not just Struts.
Initial Build Successful
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] Struts 2 Bill of Materials ......................... SUCCESS [ 1.188 s]
[INFO] Struts 2 2.5.24-SNAPSHOT ........................... SUCCESS [ 2.249 s]
[INFO] Struts 2 Core ...................................... SUCCESS [01:13 min]
[INFO] Struts Plugins ..................................... SUCCESS [ 0.232 s]
[INFO] Struts 2 Configuration Browser Plugin .............. SUCCESS [ 1.374 s]
[INFO] Struts 2 Sitemesh Plugin ........................... SUCCESS [ 1.429 s]
[INFO] Struts 2 Tiles Plugin .............................. SUCCESS [ 2.303 s]
[INFO] Struts 2 DWR Plugin ................................ SUCCESS [ 0.905 s]
[INFO] Struts 2 Spring Plugin ............................. SUCCESS [ 2.232 s]
[INFO] Struts 2 Convention Plugin ......................... SUCCESS [ 4.540 s]
[INFO] Struts 2 JUnit Plugin .............................. SUCCESS [ 4.297 s]
[INFO] Struts 2 JSON Plugin ............................... SUCCESS [ 5.384 s]
[INFO] Struts 2 Bean Validation Plugin .................... SUCCESS [ 3.345 s]
[INFO] Struts 2 Webapps ................................... SUCCESS [ 0.391 s]
[INFO] Struts 2 Showcase Webapp ........................... SUCCESS [ 6.104 s]
[INFO] Struts 2 REST Plugin ............................... SUCCESS [ 4.058 s]
[INFO] Struts 2 Rest Showcase Webapp ...................... SUCCESS [ 1.524 s]
[INFO] Struts 2 CDI Plugin ................................ SUCCESS [ 2.758 s]
[INFO] Struts 2 Embedded JSP Plugin ....................... SUCCESS [ 8.111 s]
[INFO] Struts 2 GXP Plugin ................................ SUCCESS [ 1.137 s]
[INFO] Struts 2 Jasper Reports Plugin ..................... SUCCESS [ 4.392 s]
[INFO] Struts 2 Java Templates Plugin ..................... SUCCESS [ 2.666 s]
[INFO] Struts 2 JFreeChart Plugin ......................... SUCCESS [ 3.169 s]
[INFO] Struts 2 OSGi Plugin ............................... SUCCESS [ 3.209 s]
[INFO] Struts 2 OVal Plugin ............................... SUCCESS [ 3.113 s]
[INFO] Struts 2 Pell Multipart Plugin ..................... SUCCESS [ 0.842 s]
[INFO] Struts 2 Plexus Plugin ............................. SUCCESS [ 1.003 s]
[INFO] Struts 2 Portlet Plugin ............................ SUCCESS [ 5.210 s]
[INFO] Struts 2 Portlet Tiles Plugin ...................... SUCCESS [ 0.999 s]
[INFO] DEPRECATED: Struts 2 Sitegraph Plugin .............. SUCCESS [ 2.634 s]
[INFO] Struts 2 TestNG Plugin ............................. SUCCESS [ 2.081 s]
[INFO] Struts OSGi Bundles ................................ SUCCESS [ 0.083 s]
[INFO] Struts 2 OSGi Admin Bundle ......................... SUCCESS [ 1.237 s]
[INFO] Struts 2 OSGi Demo Bundle 2.5.24-SNAPSHOT .......... SUCCESS [ 1.157 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 02:39 min
[INFO] Finished at: 2020-08-14T11:24:15+02:00
[INFO] ------------------------------------------------------------------------
Other phases
There are other phases that can be useful when working with Maven. The package phase will just JAR (or WAR) the modules. The test phase will only execute unit-tests. The compile phase will only build the source-code (but not the test sources). And the clean phase will remove all artifacts, typically the entire target directory.
Maven Tips
A few helpful tips for using Maven are provided:
Skip exporting pages from Confluence
The whole Struts2 documentation resists on Confluence and during normal build process is exported with SiteExporter tool locally to html files. To perform that, you must have an account on Confluence. In most cases you don’t need to export the whole Confluence, so you can skip this, just type command:
mvn clean install -DskipWiki
Skip creating assemblies
During normal development cycle you don’t need to create assembly packages which consist of all the libraries, example apps and docs - you can skip them as well:
mvn clean install -DskipAssembly
Offline mode
If you are disconnected from the Internet or simply wish to make your build faster, pass in the -o argument and Maven won’t check for new modules to download.
mvn -o
OutOfMemoryError
If you get an OutOfMemoryError while running the tests:
// Bash
export MAVEN_OPTS=-Xmx512m
// Windows
set MAVEN_OPTS=-Xmx512m
Skipping test execution
Although this shouldn’t ever happen, sometimes tests do fail and you need to build the framework anyway. If there’s a problem, you can pass in the skip tests parameter.
mvn -Dmaven.test.skip=true
Of course, if you find tests are failing, please submit a patch to fix them!
Debugging build failures
Struts 2 depends on the current snapshot artifact of XWork 2. Unfortunately, if XWork 2 is modified in a significant way, the Struts build doesn’t check for and retrieve a new version of the XWork snapshot jar, resulting in compilation or unit test failures.
The solution is to clear out any stale XWork 2 jars in your local Maven repository, usually by removing the directory
~/.m2/repository
This will force the Struts Maven build to pull down a fresh copy of XWork and hopefully resolve your problem.
First time building
In some cases it has been seen that Maven will complain if a module doesn’t exist, even though it is part of the current build. Often, the missing module turns up when executing
mvn package
A simple fix for this is to run
mvn install
instead. If you have to do this, it will probably only be a one time thing.