Creating the Maven Web Application project

Each Maven project has a pom.xml configuration file at the root level of the NetBeans project. Click on the Files view and double-click on the pom.xml file to open it in the editor:

The Project Object Model (POM) fully defines the project and all required Maven properties and build behaviors. There is only one dependency shown in pom.xml:

<dependencies>
  <dependency>
    <groupId>javax</groupId>
    <artifactId>javaee-web-api</artifactId>
    <version>7.0</version>
    <scope>provided</scope>
  </dependency>
</dependencies>

This dependency identifies that the project requires Java EE 7 for building. This entry ensures the full Java EE 7 APIs are available for Java coding in the Task Time Tracker project. Our project also requires the Spring Framework, which must now be added as additional dependencies. Typing in the editor will result in autocompletion help to determine the correct dependencies. After adding the Spring Framework groupId and artifactId entries, as shown in the following screenshot, the Ctrl + Space bar keyboard shortcut will open the available matching entries for the artifactId starting with the text spring:

If this autocomplete list is not available, it may be due to the Maven repository being indexed for the first time. In this situation you will then see the following screenshot at the bottom of the editor:

Be patient and in a few minutes the indexing will be finished and the autocomplete will become available. Indexing is required to download available entries from the Maven repository.

The required Spring Framework components are as follows:

To add these dependencies using the latest Spring release version (3.2.4) requires the following additions to the pom.xml file:

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>3.2.4.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context-support</artifactId>
  <version>3.2.4.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-tx</artifactId>
  <version>3.2.4.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-jdbc</artifactId>
  <version>3.2.4.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-orm</artifactId>
  <version>3.2.4.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-instrument</artifactId>
  <version>3.2.4.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-webmvc</artifactId>
  <version>3.2.4.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-test</artifactId>
  <version>3.2.4.RELEASE</version>
</dependency>

The final Spring Framework dependency is only required for testing. We can define this by adding a scope attribute with value test. This tells Maven that the dependency is only required when running the testing phase of the build and is not required for deployment.

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-test</artifactId>
  <version>3.2.4.RELEASE</version>
  <scope>test</scope>
</dependency>

The javaee-web-api dependency that was automatically created by NetBeans has a scope of provided. This means the dependency is not required for deployment and is provided by the target server. The GlassFish 4 server itself is the provider of this dependency.

If the scope attribute has not been included, the dependency JAR will be included in the final build. This is the equivalent of providing a scope entry of compile. As a result, all the Spring Framework dependency JARs will be included in the final build file.

A full explanation of the Maven dependency mechanism and scoping can be found at http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html.

The Spring Framework dependencies defined in pom.xml all have the same version (3.2.4.RELEASE). This duplication is not ideal, especially when we wish to upgrade to a newer version at a later time. Changes would be required in multiple places, one for each Spring dependency. A simple solution is to add a property to hold the release version value as shown in the following code:

<properties>
<endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<spring.version>3.2.4.RELEASE</spring.version>
</properties>

This custom property, which we have named spring.version, can now be used to replace the multiple duplicates as follows:

<dependency>
<groupId>org.springframework</groupId>
  <artifactId>spring-context-support</artifactId>
  <version>${spring.version}</version>
</dependency>

The ${spring.version} placeholder will then be substituted with the properties value during the build process.

The Maven build process executes each defined build plugin during the appropriate build phase. A full list of build plugins can be found at http://maven.apache.org/plugins/index.html. We will introduce plugins as needed in subsequent chapters, but the default plugins created by the NetBeans IDE are of interest now.

The maven-compiler-plugin controls and executes the compilation of Java source files. This plugin allows you to specify both the source and target Java versions for compilation as shown in the following code:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-compiler-plugin</artifactId>
  <version>3.1</version>
  <configuration>
    <source>1.7</source>
    <target>1.7</target>
    <compilerArguments>
      <endorseddirs>${endorsed.dir}</endorseddirs>
    </compilerArguments>
  </configuration>
</plugin>

Changing these values to 1.6 may be required when compiling projects for older Java servers running on the earlier versions of Java.

The maven-war-plugin builds a WAR file for the project as follows:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-war-plugin</artifactId>
  <version>2.3</version>
  <configuration>
    <failOnMissingWebXml>false</failOnMissingWebXml>
  </configuration>
</plugin>

The default generated WAR filename is {artifactId}-{version}.war, which can be changed by including the warName configuration property. We will be adding properties to this plugin when building the project for production release in the final chapter. A full list of maven-war-plugin options may be found at http://maven.apache.org/plugins/maven-war-plugin/war-mojo.html.

The maven-dependency-plugin copies dependency JAR files to the defined output directory as shown in the following code:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-dependency-plugin</artifactId>
  <version>2.6</version>
  <executions>
    <execution>
      <phase>validate</phase>
      <goals>
        <goal>copy</goal>
      </goals>
      <configuration>
        <outputDirectory>${endorsed.dir}</outputDirectory>
        <silent>true</silent>
        <artifactItems>
          <artifactItem>
            <groupId>javax</groupId>
            <artifactId>javaee-endorsed-api</artifactId>
            <version>7.0</version>
            <type>jar</type>
          </artifactItem>
        </artifactItems>
      </configuration>
    </execution>
  </executions>
</plugin>

This is useful to see which JARs are used by the project and to identify what transitive dependencies are required (dependencies of dependencies).

We will modify this plugin to copy all compile-time dependencies of the project to a directory in ${project.build.directory}. This special build directory is under the root folder of the project and is named target, the target destination of the build process. The updated entry will now look as follows:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-dependency-plugin</artifactId>
  <version>2.1</version>
  <executions>
    <execution>
      <id>copy-endorsed</id>
      <phase>validate</phase>
      <goals>
        <goal>copy</goal>
      </goals>
      <configuration>
        <outputDirectory>${endorsed.dir}</outputDirectory>
        <silent>true</silent>
        <artifactItems>
          <artifactItem>
            <groupId>javax</groupId>
            <artifactId>javaee-endorsed-api</artifactId>
            <version>7.0</version>
            <type>jar</type>
          </artifactItem>
        </artifactItems>
      </configuration>
    </execution> 
    <execution>
      <id>copy-all-dependencies</id>
      <phase>compile</phase>
      <goals>
        <goal>copy-dependencies</goal>
      </goals>
      <configuration>
        <outputDirectory>${project.build.directory}/lib
        </outputDirectory>
        <includeScope>compile</includeScope>
      </configuration> 
    </execution>
  </executions>
</plugin>

As we are now performing two executions in the single plugin, each execution needs its own <id>. The second execution, with ID copy-all-dependencies, will copy all dependent JARs with the scope compile to the target/lib directory.

The simplest way to execute a build is to click on the Clean and Build Project button in the toolbar. You can also right-click on the project node in the Projects tab and select Clean and Build from the menu. The build process will then execute each defined phase in the POM, resulting in Java code compilation, dependency resolution (and copying), and finally, WAR file generation. Opening the target directory structure will display the build result as follows:

Even though we have not written a single line of code, the generated WAR file task-time-tracker-1.0.war can now be deployed to the GlassFish server.