cxf:Writing a service with Spring

This example will lead you through creating your first service with Spring. You'll learn how to:

• Set up your build for CXF
• Writing a simple JAX-WS service
• Set up the HTTP transport

This example corresponds to the spring_http example in the CXF distribution.

Setting up your build

Open up your favorite IDE and create a new project. The first thing we need to do is add the necessary CXF dependencies to the project. You can find these dependencies in the CXF distribution in the lib directory.

commons-logging-1.1.jar
geronimo-activation_1.1_spec-1.0-M1.jar (or Sun's Activation jar)
geronimo-annotation_1.0_spec-1.1.jar (JSR 250)
geronimo-javamail_1.4_spec-1.0-M1.jar (or Sun's JavaMail jar)
geronimo-servlet_2.5_spec-1.1-M1.jar (or Sun's Servlet jar)
geronimo-ws-metadata_2.0_spec-1.1.1.jar (JSR 181)
jaxb-api-2.0.jar
jaxb-impl-2.0.5.jar
jaxws-api-2.0.jar
neethi-2.0.jar
saaj-api-1.3.jar
saaj-impl-1.3.jar
stax-api-1.0.1.jar
wsdl4j-1.6.1.jar
wstx-asl-3.2.1.jar
XmlSchema-1.2.jar
xml-resolver-1.2.jar

The Spring jars:

aopalliance-1.0.jar
spring-core-2.0.8.jar
spring-beans-2.0.8.jar
spring-context-2.0.8.jar
spring-web-2.0.8.jar

And the CXF jar:

cxf-2.1.jar

Writing your Service

First we'll write our service interface. It will have one operation called "sayHello" which says "Hello" to whoever submits their name.

package demo.spring;

import javax.jws.WebService;

@WebService
public interface HelloWorld {
    String sayHi(String text);
}

Our implementation will then look like this:

package demo.spring;

import javax.jws.WebService;

@WebService(endpointInterface = "demo.spring.HelloWorld")
public class HelloWorldImpl implements HelloWorld {

    public String sayHi(String text) {
        return "Hello " + text;
    }
}

The @WebService annotation on the implementation class lets CXF know which interface to use when creating WSDL. In this case its simply our HelloWorld interface.

Declaring your server beans

CXF contains support for "nice XML" within Spring 2.0. For the JAX-WS side of things, we have a <jaxws:endpoint> bean which sets up a server side endpoint.

Lets create a "beans.xml" file in our WEB-INF directory which declares an endpoint bean:

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:jaxws="http://cxf.apache.org/jaxws"
	xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://cxf.apache.org/jaxws http://cxf.apache.org/schemas/jaxws.xsd">

	<import resource="classpath:META-INF/cxf/cxf.xml" />
	<import resource="classpath:META-INF/cxf/cxf-extension-soap.xml" />
	<import resource="classpath:META-INF/cxf/cxf-servlet.xml" />

	<jaxws:endpoint 
	  id="helloWorld" 
	  implementor="demo.spring.HelloWorldImpl" 
	  address="/HelloWorld" />
	  
</beans>

If you want to reference a spring managed-bean, you can write like this:

<bean id="hello" class="demo.spring.HelloWorldImpl" />

  <jaxws:endpoint id="helloWorld" implementor="#hello" address="/HelloWorld" />

The bean uses the following properties:

• id specifies the id of the bean in the Spring context.
• implementor specifies the implementation class.
• address specifies the location the service will be hosted. This should just be a related path. This is because CXF can't know the war name and the servlet container's listening port, CXF will update the endpoint address with the request url at the runtime.

To provide a bean name instead of a classname as an implementor, simply supply the bean-name prepended with "#", e.g. implementor="#myBean".

Setting up the Servlet

We'll need to add two things to our web.xml file:

1. the Spring ContextLoaderLister. This starts Spring and loads our beans.xml file. We can specify where our file is via a context-param element.
2. the CXF Servlet

   <web-app>
   	<context-param>
   		<param-name>contextConfigLocation</param-name>
   		<param-value>WEB-INF/beans.xml</param-value>
   	</context-param>
   
   	<listener>
   		<listener-class>
   			org.springframework.web.context.ContextLoaderListener
   		</listener-class>
   	</listener>
   
   	<servlet>
   		<servlet-name>CXFServlet</servlet-name>
   		<display-name>CXF Servlet</display-name>
   		<servlet-class>
   			org.apache.cxf.transport.servlet.CXFServlet
   		</servlet-class>
   		<load-on-startup>1</load-on-startup>
   	</servlet>
   
   	<servlet-mapping>
   		<servlet-name>CXFServlet</servlet-name>
   		<url-pattern>/*</url-pattern>
   	</servlet-mapping>
   </web-app>

It is important to note that the address that you chose for your endpoint bean must be one your servlet listens on. For instance, if my Servlet was register for "/some-services/*" but my address was "/more-services/HelloWorld", there is no way CXF could receive a request.

Create a Client

CXF includes a JaxWsProxyFactory bean which create a client for you from your service interface. You simply need to tell it what your service class is (the HelloWorld interface in this case) and the URL of your service. You can then create a client bean via the JaxWsProxyFactory bean by calling it's create() method.

Here's an example:

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:jaxws="http://cxf.apache.org/jaxws"
	xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
http://cxf.apache.org/jaxws http://cxf.apache.org/schema/jaxws.xsd">

    <bean id="client" class="demo.spring.HelloWorld" 
      factory-bean="clientFactory" factory-method="create"/>
    
	<bean id="clientFactory" class="org.apache.cxf.jaxws.JaxWsProxyFactoryBean">
	  <property name="serviceClass" value="demo.spring.HelloWorld"/>
	  <property name="address" value="http://localhost:9002/HelloWorld"/>
	</bean>
	  
</beans>

If you were going to access your client you could now simply pull it out of the Spring context (or better yet, inject it into your application using Spring!):

ApplicationContext context = ...; // your Spring ApplicationContext
HellWorld client = (HelloWorld) context.getBean("client");

client code at
http://svn.apache.org/repos/asf/cxf/trunk/distribution/src/main/release/samples/java_first_spring_support/src/demo/spring/client/Client.java

Advanced Steps

For more information on using Spring you may want to read the Configuration and Spring sections of the User's Guide.