Spring Web Services 2. Made easy!

We’ll see how to develop Spring Webservices 2, along with validation on the base of xml schema. We’ll use spring-ws 2, maven, jaxb for making this sample project spring-ws2-exemplary. 

Source Code!

You don’t need to copy paste the code, it’s available for download at the bottom of the page. The project may give some errors while building due to non-conformance of Maven 3, so for that I’ve enhanced the POM and you can download the new project from here.

We’ll see the whole process in easy steps, making no big dragon of this!

1. I presume you are probably aware of maven. Setting it up is easy. If you’re not a maven-compatriot, don’t worry, google it, and you’ll have it up and running in a matter of mins.

So all said and done, lets start the development rightaway.

2. Open command prompt and navigate to your workspace location, or wherever you need to make the project.

3. Type in the following command, all in one line.

mvn archetype:create -DarchetypeGroupId=org.springframework.ws -DarchetypeArtifactId=spring-ws-archetype -DarchetypeVersion=2.0.1.RELEASE -DgroupId=ankeet.spring.ws2 -DartifactId=spring-ws2-exemplary

So there you have the basic skeleton of the project ready for you, including the spring config files, pom.xml and the requisite folder structure. Go have look 😉

4. Now you have the basic structure with you, but it still doesn’t qualifies to be imported as a project in eclipse or SpringsourceToolSuite (STS), as it lacks the .classpath and .project files.

To overcome, go to the project folder spring-ws2-exemplary in this case and run the following command:-

mvn eclipse:eclipse

Now you can import this as Existing Projects into Workspace

5. Creating the xml request and response messages. We’ll create a service SquareService, which will give the square of the input number.

So our request will be

        <SquareServiceRequest>
	   <Input>3</Input>
	</SquareServiceRequest>

and response will be

       <SquareServiceResponse>
	  <Output>9</Output>
       </SquareServiceResponse>

6. Since, you now have the request and response messages combine it into one xml file and generate the xsd.

Combining the request and response in a file spring-ws2-square.xml

<?xml version="1.0" encoding="UTF-8"?>
<SquareService xmlns="https://ankeetmaini.wordpress.com/spring-ws2-square">

	<SquareServiceRequest>
		<Input>3</Input>
	</SquareServiceRequest>

	<SquareServiceResponse>
		<Output>9</Output>
	</SquareServiceResponse>

</SquareService>

7. To generate the xsd, you can use trang.jar if you don’t have anything else. Its an open source product.

Download the latest version and unzip it on your system. Open command prompt and navigate to the unzipped folder.

To create the XSD run the following command:

java -jar trang.java <Path-of-XML-file> <Path-where-xsd-is-to-be-generated>

I copied my xml to the trang direcotory only, and generated my corresponding xsd there too, and then copied it to WEB-INF. Simple.

So you have the xsd generated in the current directory. Before putting it into use, we need to tweak it a little bit to suit our purposes.

Original spring-ws2-square.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" targetNamespace="https://ankeetmaini.wordpress.com/spring-ws2-square" xmlns:s="https://ankeetmaini.wordpress.com/spring-ws2-square">
  <xs:element name="SquareService">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="s:SquareServiceRequest"/>
        <xs:element ref="s:SquareServiceResponse"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="SquareServiceRequest">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="s:Input"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="Input" type="xs:integer"/>
  <xs:element name="SquareServiceResponse">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="s:Output"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name="Output" type="xs:integer"/>
</xs:schema></pre>

Editing it, we get the final xsd. Please note the finer details yourself, and try to comprehend. You’ll be able to figure out the need to edit it most of the times for the sake of more conciseness, and removal of extraneous elements, if you know what I mean 😉

Final spring-ws2-square.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" targetNamespace="https://ankeetmaini.wordpress.com/spring-ws2-square" xmlns:s="https://ankeetmaini.wordpress.com/spring-ws2-square">

  <xs:element name="SquareServiceRequest">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Input" type="xs:integer"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:element name="SquareServiceResponse">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Output" type="xs:integer"/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>

</xs:schema>

Now copy this to the src/main/webapp/WEB-INF folder, so that it’ll be detected at classpath.

8. Open web.xml located in WEB-INF folder and change the name of the servlet to spring-ws2 (This is not required but I do, to remove the ambiguity, if at all it arises). Don’t forget to change in the <servlet-maping> also.

Add an init param

<init-param>
			<param-name>transformWsdlLocations</param-name>
			<param-value>true</param-value>
		</init-param>

Verify your web.xml looks like this:-

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
         version="2.4">

    <display-name>Archetype Created Web Application</display-name>

 	<servlet>
		<servlet-name>spring-ws2</servlet-name>
		<servlet-class>org.springframework.ws.transport.http.MessageDispatcherServlet
		</servlet-class>
		<init-param>
			<param-name>transformWsdlLocations</param-name>
			<param-value>true</param-value>
		</init-param>
	</servlet>

    <servlet-mapping>
        <servlet-name>spring-ws2</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

</web-app>

9. Now, since you changed the servlet’s name, you need to change the Spring’s configuration file too, because the container will look for <servlet-name>-servlet.xml

Rename (or better Refactor) it to spring-ws2-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:sws="http://www.springframework.org/schema/web-services"
       xsi:schemaLocation="http://www.springframework.org/schema/beans	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
       http://www.springframework.org/schema/context
	   http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/web-services                      	http://www.springframework.org/schema/web-services/web-services-2.0.xsd">

    <!-- To detect @Endpoint -->
<sws:annotation-driven/>

<!-- To detect @Service, @Component etc -->
<context:component-scan base-package="ankeet.spring" />

    <!-- To generate dynamic wsdl -->
	<sws:dynamic-wsdl
		id="getSquare"
		portTypeName="SquareService"
		locationUri="/squareService"
		targetNamespace="https://ankeetmaini.wordpress.com/spring-ws2-square">
		<sws:xsd location="/WEB-INF/spring-ws2-square.xsd"/>
	</sws:dynamic-wsdl>

    <!-- For validating your request and response -->
    <!-- So that you don't send a string instead of an integer -->

	 <sws:interceptors>
<bean id="validatingInterceptor"
        class="org.springframework.ws.soap.server.endpoint.interceptor.PayloadValidatingInterceptor">
    <property name="schema" value="/WEB-INF/spring-ws2-square.xsd"/>
    <property name="validateRequest" value="true"/>
    <property name="validateResponse" value="true"/>
</bean>
  </sws:interceptors>

</beans>

10. In Eclipse/STS right click your project and and then new, and select a new source folder and name it as src/main/java

Create three packages : ankeet.spring.ws2.endpoint, ankeet.spring.ws2.service, ankeet.spring.ws2.generated

11. Since we’re using jaxb for converting xml <—> object, we need to make changes to the pom.xml to add its dependencies and plugins, so that the Java Classes are generated at compile time from the XSD given.

Add the following piece of code to the pom in the <plugins> section

<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>jaxb2-maven-plugin</artifactId>
  <executions>
    <execution>
      <goals>
	<goal>xjc</goal>
      </goals>
     </execution>
   </executions>
  <configuration>
    <schemaDirectory>src/main/webapp/WEB-INF/</schemaDirectory>
  </configuration>
</plugin>

Similarly add the dependencies in the <dependencies> section of POM.

<dependency>
  <groupId>javax.xml.bind</groupId>
  <artifactId>jaxb-api</artifactId>
  <version>2.0</version>
</dependency>
<dependency>
  <groupId>com.sun.xml.bind</groupId>
  <artifactId>jaxb-impl</artifactId>
  <version>2.0.3</version>
</dependency>
<dependency>
  <groupId>org.apache.xmlbeans</groupId>
  <artifactId>xmlbeans</artifactId>
  <version>2.4.0</version>
</dependency>
<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.8.1</version>
  <scope>test</scope>
</dependency>
<dependency>
  <groupId>log4j</groupId>
  <artifactId>log4j</artifactId>
  <scope>compile</scope>
  <version>1.2.16</version>
</dependency>

11. Write the endpoint class as follows:-

SquareWSEndpoint.java

/**
 *
 */
package ankeet.spring.ws2.endpoint;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.ws.server.endpoint.annotation.Endpoint;
import org.springframework.ws.server.endpoint.annotation.PayloadRoot;
import org.springframework.ws.server.endpoint.annotation.RequestPayload;
import org.springframework.ws.server.endpoint.annotation.ResponsePayload;

import ankeet.spring.ws2.generated.*;
import ankeet.spring.ws2.generated.SquareServiceResponse;
import ankeet.spring.ws2.service.SquareService;

/**
 * @author Ankeet Maini
 *
 */
@Endpoint
public class SquareWSEndpoint {
	//To calculate square of the input.
	@Autowired
	private SquareService squareService;
	//This is like @RequestMapping of Spring MVC
	@PayloadRoot(localPart="SquareServiceRequest", namespace="https://ankeetmaini.wordpress.com/spring-ws2-square")
	@ResponsePayload
	public SquareServiceResponse getSquare(@RequestPayload SquareServiceRequest request) {
		SquareServiceResponse response = new ObjectFactory().createSquareServiceResponse();
		response.setOutput(squareService.square(request.getInput()));
		return response;
	}
}

12. Now write the service classes which will actually do the squaring.

SquareService.java

package ankeet.spring.ws2.service;

import java.math.BigInteger;

public interface SquareService {
	public BigInteger square(BigInteger bigInteger);

}

And it’s implementation class SquareServiceImpl.java

package ankeet.spring.ws2.service;

import java.math.BigInteger;

import org.springframework.stereotype.Service;

@Service
public class SquareServiceImpl implements SquareService {

	public BigInteger square(BigInteger bigInteger) {
		return (bigInteger.multiply(bigInteger));
	}

}

13. Now when you clean your project JAXB will create the classes from the XSD present on the classpath, in our case spring-ws2-square.xsd located in WEB-INF. The code generated will be in the target folder, so you’ll have to copy the files and put into the ankeet.spring.ws2.generated package, and correct the inconsistencies arising in the package names by shifting. Also, make src/main/webapp a source folder(By navigating to webapp and then right clicking and in Configure Buildpath, make it a source folder).

14. After this your project structure should prcisely look like this.

15. To run the project you can create a war and deploy on the server, or use maven. Go the project directory and type the following command to run the project on tomcat server:

mvn tomcat:run

16. Open your web browser and enter the following url

http://localhost:8080/spring-ws2-exemplary/getSquare.wsdl to see the WSDL file generated.

17. To test the application, you can build a client or use Soap UI. To test with soap UI, open it, create an new project and give it the above url of WSDL.

Press Ok.

Click on Request1 and on the left side an interface will appear asking your request. Enter any integer and press the green button to send it to the server. If you enter anything other than an integer, a Validation error will be reported on the other side.

and if you do enter any thing else than integer, say a string, the Validation will fail and you’ll get the following error.

Just in case if you wish to know, the above Response is

<pre><SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
   <SOAP-ENV:Header/>
   <SOAP-ENV:Body>
      <SOAP-ENV:Fault>
         <faultcode>SOAP-ENV:Client</faultcode>
         <faultstring xml:lang="en">Validation error</faultstring>
         <detail>
            <spring-ws:ValidationError xmlns:spring-ws="http://springframework.org/spring-ws">cvc-datatype-valid.1.2.1: 'a' is not a valid value for 'integer'.</spring-ws:ValidationError>
            <spring-ws:ValidationError xmlns:spring-ws="http://springframework.org/spring-ws">cvc-type.3.1.3: The value 'a' of element 'spr:Input' is not valid.</spring-ws:ValidationError>
         </detail>
      </SOAP-ENV:Fault>
   </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

The code is hosted on Google Codes, to download the project click here.

To run it, just unzip the file, open command prompt, navigate to the directory and type : mvn tomcat:run, and voila you’re done!

While creating this project I read a lot, and found these blogs extremely helpful,

1. Jamesbnuzzo

2. Ice09

3. krams

That’s all for this one. Enjoy building and running it. 🙂