Spring Tutorials

Spring Web Services (Spring-WS) is a product of the Spring community focused on creating document-driven Web services. Spring Web Services aims to facilitate contract-first SOAP service development, allowing for the creation of flexible web services using one of the many ways to manipulate XML payloads. The product is based on Spring itself, which means you can use the Spring concepts such as dependency injection as an integral part of your Web service.

Spring-WS uses alternative SOAP stacks lacking when it comes to following Web service best practices. Spring-WS makes the best practice an easy practice. This includes practices such as the WS-I basic profile, Contract-First development, and having a loose coupling between contract and implementation.

Any application can have a Web Service component and these components can be created regardless of any language or platform. In this series of blogs we will cover all useful aspects related to Web Services in Spring. A Web Service there are two main approaches of doing this:

1. Contract First Web Services
2. Contract Last Web Services

There are some important features of Spring Web Services as follows:

1. Makes the Best Practice: Spring Web Services makes enforcing best practices easier. This includes practices such as the WS-I basic profile, Contract-First development, and having a loose coupling between contract and implementation.
2. Powerful mappings: You can distribute incoming XML requests to any object, depending on message payload, SOAP Action header, or an XPath expression.
3. XML API support: Incoming XML messages can be handled not only with standard JAXP APIs such as DOM, SAX, and StAX, but also JDOM, dom4j, XOM, or even marshalling technologies.
4. Flexible XML Marshalling: The Object/XML Mapping module in the Spring Web Services distribution supports JAXB 1 and 2, Castor, XMLBeans, JiBX, and XStream. And because it is a separate module, you can use it in non-Web services code as well.
5. Reuses your Spring expertise: Spring-WS uses Spring application contexts for all configuration, which should help Spring developers get up-to-speed nice and quickly. Also, the architecture of Spring-WS resembles that of Spring-MVC.
6. Supports WS-Security: WS-Security allows you to sign SOAP messages, encrypt and decrypt them, or authenticate against them.
7. Integrates with Acegi Security: The WS-Security implementation of Spring Web Services provides integration with Acegi Security. This means you can use your existing Acegi configuration for your SOAP service as well.
8. Built by Maven: This assists you in effectively reusing the Spring Web Services artifacts in your own Maven-based projects.
9. Apache license: You can confidently use Spring-WS in your project.

<beans xmlns="http://www.springframework.org/schema/beans">
<bean id="webServiceClient" class="WebServiceClient">
<property name="defaultUri" value="http://localhost:8080/WebService"/>
</bean>
</beans>

Spring Web Services requires a standard Java 1.5 Runtime Environment. Java 1.6 is also supported. Spring-WS also requires Spring 3.0 or higher. Spring-WS consists of a number of modules are described as follows:

1. The XML module (spring-xml.jar) contains various XML support classes for Spring Web Services. This module is mainly intended for the Spring-WS framework itself, and not a Web service developers.
2. The Core module (spring-ws-core.jar) is the central part of the Spring's Web services functionality. It provides the central WebServiceMessage and SoapMessage interfaces, the server-side framework, with powerful message dispatching, and the various support classes for implementing Web service endpoints; and the client-side WebServiceTemplate.
3. The Support module (spring-ws-support.jar) contains additional transports (JMS, Email, and others).
4. The Security package (spring-ws-security.jar) provides a WS-Security implementation that integrates with the core Web service package. It allows you to add principal tokens, sign, and decrypt and encrypt SOAP messages.

The following figure shows the Spring-WS modules and the dependencies between them. Arrows indicate dependencies, i.e. Spring-WS Core depends on Spring-XML and the OXM module.