Consuming Services – the Spring Web Service Client

There is a downloadable zipped Eclipse project at the end of this post.

Having created a sample (mail) web service some posts ago, we would like to have a client consuming this service.

With Spring Web Services, this can easily be done by using the ubiquitous Template Pattern and, in this special case, the WebServiceTemplate . As the project structure can be downloaded, only the two important snippets are shown here:

The application-config.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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">

    <bean id="mailclient" class="de.mail.MailClient">
    	<property name="webServiceTemplate" ref="webServiceTemplate"/>
    </bean>

    <bean id="messageFactory" class="org.springframework.ws.soap.saaj.SaajSoapMessageFactory"/>

    <bean id="webServiceTemplate" class="org.springframework.ws.client.core.WebServiceTemplate">
        <constructor-arg ref="messageFactory"/>
        <property name="marshaller" ref="marshaller"/>
        <property name="unmarshaller" ref="marshaller"/>
        <property name="defaultUri" value="http://localhost:8080/mailservice"/>
    </bean>

    <bean id="marshaller" class="org.springframework.oxm.jaxb.Jaxb2Marshaller">
		<property name="classesToBeBound">
			<list>
				<value>org.mail.mailschema.MailRequest</value>
				<value>org.mail.mailschema.MailResponse</value>
			</list>
		</property>
	</bean>

</beans>

and the actual Web Service client:

package de.mail;

import org.mail.mailschema.MailRequest;
import org.mail.mailschema.MailResponse;
import org.springframework.ws.client.core.WebServiceTemplate;

public class MailClient {

	private WebServiceTemplate webServiceTemplate;

	public void setWebServiceTemplate(WebServiceTemplate webServiceTemplate) {
		this.webServiceTemplate = webServiceTemplate;
	}

	public boolean send(String user, String password, String from, String to, String subject, String content) {
		MailRequest request = new MailRequest();
		request.setFrom(from);
		request.setTo(to);
		request.setUser(user);
		request.setPassword(password);
		request.setContent(content);
		request.setSubject(subject);
		return ((MailResponse)webServiceTemplate.marshalSendAndReceive(request)).isResult();
	}

}

The servlet sample is not shown, since it is just for demonstration and not a nice piece of code. However, it exemplifies some Spring antipatterns, because DI is not used and the servlet is not Springified at all. But it’s only a sample showing how to use the Web Service client.
By deploying the servlet (or using mvn jetty:run again), a mail can be send by calling http://server/mailwebapp/Mailer?user=USER&password=PASSWORD&to=RECIPIENT@BLA.DE&from=me&subject=SUBJECT&content=MAILTEXT
But the actual code could be much nicer (also, it is definitely not safe – just a counter and a whitelist is added to prevent immediate abuse )

Sample Mail Web Service client project:

Instructions:

1. Download the wsclient-sample
2. Download the mailwebapp-sample
3. Download the maildatabinding

If correctly imported as Eclipse projects, the dependencies should be automatically resolved.
The mailwebapp can be deployed as a usual Web application which uses the Web Service client to call the Mail Web Service, which must be already deployed (compare the Spring Web Service post).

Mailing with Velocity

Download Eclipse project

Java Mailing is also leveraged by Spring, in the usual templating way some optimisations have been added. Therefore, we will write a small mailing application here.
We will add Velocity for mail templating.

• As always, start with a simple Maven project.
• The following part is almost copied from the Spring Email manual

MailSample:

package sample.mail;

import java.util.HashMap;
import java.util.Map;

import javax.mail.internet.MimeMessage;

import org.apache.velocity.app.VelocityEngine;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.mail.javamail.MimeMessagePreparator;
import org.springframework.ui.velocity.VelocityEngineUtils;

public class MailSample {

	private JavaMailSender mailSender;
	private VelocityEngine velocityEngine;

	public void setMailSender(JavaMailSender mailSender) {
		this.mailSender = mailSender;
	}

	public void setVelocityEngine(VelocityEngine velocityEngine) {
		this.velocityEngine = velocityEngine;
	}

	public static void main(String[] args) throws Exception {
		ApplicationContext app = new ClassPathXmlApplicationContext(
				"applicationContext.xml");
		MailSample mailer = (MailSample) app.getBean("mailer");
		mailer.send();
	}

	private void send() {
	      MimeMessagePreparator preparator = new MimeMessagePreparator() {
	          public void prepare(MimeMessage mimeMessage) throws Exception {
	             MimeMessageHelper message = new MimeMessageHelper(mimeMessage);
	             message.setTo("mail.receiver@web.de");
	             message.setFrom("mail.sender@web.de"); // could be parameterized...
	             Map model = new HashMap();
	             model.put("key", "testtext");
	             String text = VelocityEngineUtils.mergeTemplateIntoString(
	                velocityEngine, "test.vm", model);
	             message.setText(text, true);
	          }
	       };
	       this.mailSender.send(preparator);
	}
}

• the following part is also copied from the Email tutorial.

applicationContext.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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">

	<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
<property name="host">
			<value>server.com</value>
		</property>
<property name="javaMailProperties">
<props>
<prop key="mail.smtp.auth">true</prop>
			</props>
		</property>
<property name="username"><value>username</value></property>
<property name="password"><value>password</value></property>
	</bean>

	<bean id="mailer" class="sample.mail.MailSample">
<property name="mailSender" ref="mailSender" />
<property name="velocityEngine" ref="velocityEngine" />
	</bean>

   <bean id="velocityEngine" class="org.springframework.ui.velocity.VelocityEngineFactoryBean">
<property name="velocityProperties">
         <value>
            resource.loader=class
            class.resource.loader.class=org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader
         </value>
      </property>
   </bean>

</beans>

• we just need two more files, of course the POM.

POM:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>velocitymail</groupId>
  <artifactId>velocitymail</artifactId>
  <name>velocitymail</name>
  <version>0.0.1-SNAPSHOT</version>
  <description/>
  <dependencies>
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>spring</artifactId>
  		<version>2.5.5</version>
  	</dependency>
  	<dependency>
  		<groupId>javax.mail</groupId>
  		<artifactId>mail</artifactId>
  		<version>1.4</version>
  	</dependency>
  	<dependency>
  		<groupId>velocity</groupId>
  		<artifactId>velocity</artifactId>
  		<version>1.4</version>
  	</dependency>
  </dependencies>
</project>

• and the velocity template, which is very simple in this case.

test.vm:

hello $key

and finally the project structure: