36.3. WSDL-to-Java Maven Plug-In

Overview

In contrast to the Java-first approach, which starts with a Java interface and then generates the WSDL contract, the WSDL-first approach needs to generate Java stub code from the WSDL contract.
To generate Java stub code from the WSDL contract, you can use either the ws2java command-line utility or the cxf-codegen-plugin Maven plug-in. The plug-in approach is ideal for Maven-based projects: after you paste the requisite plug-in configuration into your POM file, the WSDL-to-Java code generation step is integrated into your build.

Configure the WSDL-to-Java Maven plug-in

Configuring the WSDL-to-Java Maven plug-in is relatively easy, because most of the default configuration settings can be left as they are. After copying and pasting the sample plugin element into your project's POM file, there are just a few basic settings that need to be customized, as follows:
  • CXF version—make sure that the plug-in's dependencies are using the latest version of Apache CXF.
  • WSDL file location—specify the WSDL file location in the configuration/wsdlOptions/wsdlOption/wsdl element.
  • Location of output—specify the root directory of the generated Java source files in the configuration/sourceRoot element.
For example, the following POM fragment shows how to configure the cxf-codegen-plugin plug-in to generate Java stub code from the CustomerService.wsdl WSDL file:
<project ...>
  ...
  <parent>
    <groupId>com.fusesource.byexample.cxf-webinars</groupId>
    <artifactId>cxf-webinars</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>
  
  <build>
    <defaultGoal>install</defaultGoal>
    <plugins>
      ...
      <plugin>
        <groupId>org.apache.cxf</groupId>
        <artifactId>cxf-codegen-plugin</artifactId>
        <version>${cxf-version}</version>
        <executions>
          <execution>
            <id>generate-sources</id>
            <phase>generate-sources</phase>
            <configuration>
              <!-- Maven auto-compiles any source files under target/generated-sources/ -->
              <sourceRoot>${basedir}/target/generated-sources/jaxws</sourceRoot>
              <wsdlOptions>
                <wsdlOption>
                  <wsdl>${basedir}/../src/main/resources/wsdl/CustomerService.wsdl</wsdl>
                </wsdlOption>
              </wsdlOptions>
            </configuration>
            <goals>
              <goal>wsdl2java</goal>
            </goals>
          </execution>
        </executions>
      </plugin>

    </plugins>
  </build>

</project>

Generated Java source code

With the sample configuration shown here, the generated Java source code is written under the target/generated-sources/jaxws directory. Note that the Web service implementation is dependent on this generated stub code—for example, the service implementation class must implement the generated CustomerService SEI.

Adding the generated source to an IDE

If you are using an IDE such as Eclipse or Intellij's IDEA, you need to make sure that the IDE is aware of the generated Java code. For example, in Eclipse it is necessary to add the target/generated-sources/jaxws directory to the project as a source code directory.

Compiling the generated code

You must ensure that the generated Java code is compiled and added to the deployment package. By convention, Maven automatically compiles any source files that it finds under the following directory:
BaseDir/target/generated-sources/
Hence, if you configure the output directory as shown in the preceding POM fragment, the generated code is automatically compiled by Maven.

Reference

For full details of how to configure the Java-to-WSDL plug-in, see the Maven cxf-codegen-plugin reference page.