Spring WS 2 and Spring 3 MVC Integration Tutorial

In this tutorial we will integrate Spring WS 2 and Spring 3 MVC. We will develop a Spring WS web service that follows a Contract-First development. We will also take advantage of the latest Spring WS 2.0.0 RC2 features and use marshalling techniques to efficiently manipulate XML requests. We will use Spring 3 MVC to display our list of subscribers. It's highly recommended to read first the Spring WS: A Tutorial Using the Latest 2.0.0 RC2 Build because that's the foundation of this tutorial.

What is Spring Web Services (WS)?

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.

Source: Spring WS Reference 2.0

What is Contract-First development?

When creating Web services, there are two development styles: Contract Last and Contract First. When using a contract-last approach, you start with the Java code, and let the Web service contract (WSDL, see sidebar) be generated from that. When using contract-first, you start with the WSDL contract, and use Java to implement said contract.

Source: Spring WS Reference 2.0

For an in-depth look of Spring WS, I suggest my readers to visit the Spring WS Reference 2.0 and the Spring WS API 2.0.0.RC2

We begin by defining our requirements. We have a magazine business. Our business partner has clients that needs to subscribe with our magazine. To expose this feature, we decided to use a web service. Our contract is that the clients will send the following information:

subscription code
name
email

Our web service will send a reply if the subscription is successful or not. The reply will contain the following elements:

status code
description

Since all web services are ultimately XML message, we need to define the format of our messages. We will create an XSD file. If you're not familiar with XSD, please see the excellent XSD tutorial w3schools.com XML Schema Tutorial.

Here's our XSD document:

subscription.xsd

This XSD is comprised of simple and complex element types. Each simple element has been assigned with restriction. In this way we can filter data even before it comes to our service. It's also a good way to validate XML data. Spring WS will handle the validation based on these restrictions.

When the client sends a request, we receive an XML document. Using Java's object-oriented approach and XML approach is not really convenient when manipulating information. Therefore we will use marshalling techniques to map the XML document with a corresponding Java object.

First let's see the actual XML document that is sent to us by the client:

Take note that this XML format is not arbitrary! The client has to honor the format that we declared in the XSD document.

Let's map this document to a SubscriptionRequest class:

SubscriptionRequest

For every request sent by the client, we send a response. We declare a SubscriptionResponse object:

Our marshaller will automatically convert this class into an XML document. If you look at the XSD file, we have declared a subscriptionResponse element.


This has been declared so that the client who is reading our WSDL will see what kind of response he will receive. Hence, the Contract-First development.

When the client receives a response, this is what he actually gets:

Our class has been automatically converted to XML.

To convert Java objects to XML and vice-versa we use Castor as our marshaller/unmarshaller implementation. For more info about Castor, check the reference guide Castor XML Mapping. There are other marshallers available, such as JAXB and JiBX. Check the Spring WS Reference Guide Chapter 8. Marshalling XML using O/X Mapper for more info.

To use Castor we need to declare a mapping file:

castor-mapping.xml

We're done with our contract. We now start the actual development!

The programming model of Spring WS 2 is similar with the programming model of Spring 3 MVC. Keep that in mind. In Spring MVC, to declare a controller, we mark the name of the class with @Controller and @RequestMapping. For example:

In Spring WS, we have a corresponding controller as well. Actually, it's called an endpoint. To declare an endpoint, we mark it with @Endpoint. For example:

In Spring MVC, to expose a method for a particular request, we add the @RequestMapping annotation and the associated URI template value and the type of method. For example:

In Spring WS, to expose a method for a particular service request, we add the @PayloadRoot annotation and the associated localPart and namespace values. For example:

The method is also annotated with @ResponsePayload, indicating that the return value ( SubscriptionResponse) is used as the payload of the response message. The method takes a SubscriptionRequest as a parameter, annotated with @RequestPayload. This means that the payload of the message is passed on this method as a DOM element. If you have omitted these two annotations, you will encounter a "java.lang.IllegalStateException: No adapter for endpoint".

Let's now declare our SubscriptionEndpoint class:

SubscriptionEndpoint

This endpoint has one method named processSubscription. It takes a SubscriptionRequest and delegates the processing to a SubscriptionService. If the subscription is successful a SUCCESS response is sent. If it failed, a FAILURE response is sent.

Here's the SubscriptionService:

SubscriptionService

We're done with the Spring WS part. We now start the Spring MVC development.

What we're adding here are just basically a single controller and single JSP file to display our subscribers. Here's a screenshot of our subscribers list:

Here's the controller:

MainController

This controller declares a single mapping:

/main/subscribers

This mapping delegates the call to the SubscriptionService. This is the same service that's utilized by Spring WS earlier!

Here's the JSP file:

We're done will all our classes. What's left are the XML configurations. We start by declaring the web.xml file:

web.xml

All request are handled by Spring MVC's DispatcherServlet. In a stand-alone Spring WS, we use the MessageDispatcherServlet instead. But since we're now integrating both, we need a way to resolve our dispatchers hierarchy.

As an alternative to the MessageDispatcherServlet, you can wire up a MessageDispatcher in a standard, Spring-Web MVC DispatcherServlet. By default, the DispatcherServlet can only delegate to Controllers, but we can instruct it to delegate to a MessageDispatcher by adding a WebServiceMessageReceiverHandlerAdapter to the servlet's web application context:

Spring WS 2 Reference 5.3.2. Wiring up Spring-WS in a DispatcherServlet

I suggest to read the Spring WS 2 reference for a thorough description of this integration.

If you examine carefully the servlet element, we've declared an init-param. This is required to dynamically convert WSDLs regardless where you deploy it. There's no need to manually set the URL of your WSDL anymore, though you still can.

In the web.xml we declared a servlet-name spring. By convention, we must declare a spring-servlet.xml as well.

spring-servlet.xml

By convention, we must declare an applicationContext.xml as well.

applicationContext.xml

These beans activate Spring's annotation support for Spring 3 MVC. At the bottom portion we import an external configuration file spring-ws.xml. This contains all the Spring WS specific configuration. In a normal Spring project, it's typical to have multiple XML configs. To lessen the XML hell experience, it's advisable we group related configurations in their owned XML file.

Here's spring-ws.xml:

spring-ws.xml

This configuration uses the latest Spring WS 2.0.0 RC2 features (unlike if you're still using 1.5.9).

What's new with Spring WS 2.0.0 RC2?

The most important new feature in this release is the update of the Spring-WS XML namespace, which now contains <sws:annotation-driven/> and <sws:interceptors/> elements (similar to the Spring-MVC namespace), and <sws:static-wsdl/> and <sws:dynamic-wsdl/> for exporting your WSDLs.

Source: SpringSource Forum: Spring Web Services 2.0.0 RC2 released

It's worth mentioning in the spring-ws.xml, we're using a pluggable endpoint adapter

DefaultMethodEndpointAdapter

and a marshalling method processor

MarshallingPayloadMethodProcessor

If you visit some of the popular Spring WS tutorials, they still use the old GenericMarshallingMethodEndpointAdapter. However, this is already deprecated in favor of a pluggable adapter.

Class GenericMarshallingMethodEndpointAdapter

Deprecated. as of Spring Web Services 2.0, in favor of DefaultMethodEndpointAdapter and MarshallingPayloadMethodProcessor.

See Spring WS API 2.0.0 GenericMarshallingMethodEndpointAdapter

That concludes our Spring WS development. We've managed to setup a simple Spring 3 WS application using the latest Spring WS 2.0.0.RC2 build. We've utilized the latest annotation features. We've also leveraged Spring 3 MVC's programming model.

To test the application, you will need to deploy it in a server, like Tomcat. For the client, unless you know how to develop a Web Service client, I advise my readers to use Soap UI for testing. They have a free version at http://soapui.org/. It's also one of the recommended tools at the official Spring Web Services site at http://static.springsource.org/spring-ws/sites/2.0/resources.html.

Here's a sample screenshot using SOAP UI to test the application:

To access the service endpoint, use the following URL:

http://localhost:8080/spring-ws/krams/ws

To access the WSDL, use the following URL (you can use Firefox to check this out):

http://localhost:8080/spring-ws/krams/ws/subscription.wsdl

To access the subscribers page, use the following URL:

http://localhost:8080/spring-ws/krams/main/subscribers

The best way to learn further is to try the actual application.

Download the project
You can access the project site at Google's Project Hosting at http://code.google.com/p/spring-ws-2-0-0-rc2-tutorial/

You can download the project as a Maven build. Look for the spring-ws.zip in the Download sections.

You can run the project directly using an embedded server via Maven.
For Tomcat: mvn tomcat:run
For Jetty: mvn jetty:run

If you want to learn more about Spring MVC and integration with other technologies, feel free to read my other tutorials in the Tutorials section.

---

Share the joy: blogger tutorials Social Bookmarking Blogger Widget I'm reading: Spring WS 2 and Spring 3 MVC Integration Tutorial ~

Subscribe by reader Subscribe by email Share

Spring WS: A Tutorial Using the Latest 2.0.0 RC2 Build

In this tutorial we will develop a simple Spring WS that follows a Contract-First development. We will also take advantage of the latest Spring WS 2.0.0 RC2 features. We will also use marshalling techniques to efficiently manipulate XML requests. This will also be our basis for the next tutorial: Spring WS and Spring MVC Integration.

What is Spring Web Services (WS)?

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.

Source: Spring WS Reference 2.0

What is Contract-First development?

When creating Web services, there are two development styles: Contract Last and Contract First. When using a contract-last approach, you start with the Java code, and let the Web service contract (WSDL, see sidebar) be generated from that. When using contract-first, you start with the WSDL contract, and use Java to implement said contract.

Source: Spring WS Reference 2.0

For an in-depth look of Spring WS, I suggest my readers to visit the Spring WS Reference 2.0 and the Spring WS API 2.0.0.RC2

Unlike with my previous tutorials, there's no Spring MVC here. However, we will still use some of the convenient tools from Spring MVC like the @Service annotation.

We begin by defining our requirements. We have a magazine business. Our business partner has clients that needs to subscribe with our magazine. To expose this feature, we decided to use a web service. Our contract is that the clients will send the following information:

subscription code
name
email

Our web service will send a reply if the subscription is successful or not. The reply will contain the following elements:

status code
description

Since all web services are ultimately XML message, we need to define the format of our messages. We will create an XSD file. If you're not familiar with XSD, please see the excellent XSD tutorial w3schools.com XML Schema Tutorial.

Here's our XSD document:

subscription.xsd

This XSD is composed of simple and complex element types. Each simple element has been assigned with restriction. In this way we can filter data even before it comes to our service. It's also a good way to validate XML data. Spring WS will handle the validation based on these restrictions.

When the client sends a request, we receive an XML document. Using Java's object-oriented approach and XML approach is not really convenient when manipulating information. Therefore we will use marshalling techniques to map the XML document with a corresponding Java object.

First let's see the actual XML document that is sent to us by the client:

Take note that this XML format is not arbitrary! The client has to honor the format that we declared in the XSD document.

Let's map this document to a SubscriptionRequest class:

SubscriptionRequest

For every request sent by the client, we send a response. We declare a SubscriptionResponse object:

Our marshaller will automatically convert this class into an XML document. If you look at the XSD file, we have declared a subscriptionResponse element.


This has been declared so that the client who is reading our WSDL will see what kind of response he will receive. Hence, the Contract-First development.

When the client receives a response, this is what he actually gets:

Our class has been automatically converted to XML.

To convert Java objects to XML and vice-versa we use Castor as our marshaller/unmarshaller implementation. For more info about Castor, check the reference guide Castor XML Mapping. There are other marshallers available, such as JAXB and JiBX. Check the Spring WS Reference Guide Chapter 8. Marshalling XML using O/X Mapper for more info.

To use Castor we need to declare a mapping file:

castor-mapping.xml

We're done with our contract. We now start the actual development!

The programming model of Spring WS 2 is similar with the programming model of Spring 3 MVC. Keep that in mind. In Spring MVC, to declare a controller, we mark the name of the class with @Controller and @RequestMapping. For example:

In Spring WS, we have a corresponding controller as well. Actually, it's called an endpoint. To declare an endpoint, we mark it with @Endpoint. For example:

In Spring MVC, to expose a method for a particular request, we add the @RequestMapping annotation and the associated URI template value and the type of method. For example:

In Spring WS, to expose a method for a particular service request, we add the @PayloadRoot annotation and the associated localPart and namespace values. For example:

The method is also annotated with @ResponsePayload, indicating that the return value ( SubscriptionResponse) is used as the payload of the response message. The method takes a SubscriptionRequest as a parameter, annotated with @RequestPayload. This means that the payload of the message is passed on this method as a DOM element. If you have omitted these two annotations, you will encounter a "java.lang.IllegalStateException: No adapter for endpoint".

Let's now declare our SubscriptionEndpoint class:

SubscriptionEndpoint

This endpoint has one method named processSubscription. It takes a SubscriptionRequest and delegates the processing to a SubscriptionService. If the subscription is successful a SUCCESS response is sent. If it failed, a FAILURE response is sent.

Here's the SubscriptionService:

SubscriptionService

We're done will all our classes. What's left are the XML configurations. We start by declaring the web.xml file:

In a normal Spring MVC application, we dispatch all request to a DispatcherServlet. With Spring WS, we use the MessageDispatcherServlet instead. If you examine carefully the servlet element, we've declared an init-param. This is required to dynamically convert WSDLs regardless where you deploy it. There's no need to manually set the URL of your WSDL anymore, though you still can.

In the web.xml we declared a servlet-name spring. By convention, we must declare a spring-servlet.xml as well.

spring-servlet.xml

These beans activate Spring's annotation support and some of Spring 3 MVC's convenient annotations like @Service. At the bottom portion we import an external configuration file spring-ws.xml. This contains all the Spring WS specific configuration. In a normal Spring project, it's typical to have multiple XML configs. To lessen the XML hell experience, it's advisable we group related configurations in their owned XML file.

Here's spring-ws.xml:

spring-ws.xml

This configuration uses the latest Spring WS 2.0.0 RC2 features (unlike if you're still using 1.5.9).

What's new with Spring WS 2.0.0 RC2?

The most important new feature in this release is the update of the Spring-WS XML namespace, which now contains <sws:annotation-driven/> and <sws:interceptors/> elements (similar to the Spring-MVC namespace), and <sws:static-wsdl/> and <sws:dynamic-wsdl/> for exporting your WSDLs.

Source: SpringSource Forum: Spring Web Services 2.0.0 RC2 released

It's worth mentioning in the spring-ws.xml, we're using a pluggable endpoint adapter

DefaultMethodEndpointAdapter

and a marshalling method processor

MarshallingPayloadMethodProcessor

If you visit some of the popular Spring WS tutorials, they still use the old GenericMarshallingMethodEndpointAdapter. However, this is already deprecated in favor of a pluggable adapter.

Class GenericMarshallingMethodEndpointAdapter

Deprecated. as of Spring Web Services 2.0, in favor of DefaultMethodEndpointAdapter and MarshallingPayloadMethodProcessor.

See Spring WS API 2.0.0 GenericMarshallingMethodEndpointAdapter

That concludes our Spring WS development. We've managed to setup a simple Spring 3 WS application using the latest Spring WS 2.0.0.RC2 build. We've utilized the latest annotation features. We've also leveraged Spring 3 MVC's programming model.

To test the application, you will need to deploy it in a server, like Tomcat. For the client, unless you know how to develop a Web Service client, I advise my readers to use Soap UI for testing. They have a free version at http://soapui.org/. It's also one of the recommended tools at the official Spring Web Services site at http://static.springsource.org/spring-ws/sites/2.0/resources.html.

Here's a sample screenshot using SOAP UI to test the application:

To access the service endpoint, use the following URL:

http://localhost:8080/spring-ws-standalone/krams/ws

To access the WSDL, use the following URL (you can use Firefox to check this out):

http://localhost:8080/spring-ws-standalone/krams/ws/subscription.wsdl

The best way to learn further is to try the actual application.

Download the project
You can access the project site at Google's Project Hosting at http://code.google.com/p/spring-ws-2-0-0-rc2-tutorial/

You can download the project as a Maven build. Look for the spring-ws-standalone.zip in the Download sections.

You can run the project directly using an embedded server via Maven.
For Tomcat: mvn tomcat:run
For Jetty: mvn jetty:run

If you want to learn more about Spring MVC and integration with other technologies, feel free to read my other tutorials in the Tutorials section.

---

Share the joy: blogger tutorials Social Bookmarking Blogger Widget I'm reading: Spring WS: A Tutorial Using the Latest 2.0.0 RC2 Build ~

Subscribe by reader Subscribe by email Share

Spring Security 3 - MVC Integration: Using A Custom Authentication Manager

In this tutorial we will create a simple Spring 3 MVC application with authentication and authorization support using Spring Security 3. We will implement a custom authentication manager for our custom requirement. This tutorial is a variation of the Spring Security - MVC Integration Tutorial (Part 2). It's highly recommended that you read that first before you read further. This tutorial will focus on the differences from the previous tutorial. Most of the code are still exactly the same in both tutorials.

Note: I suggest reading the following tutorial as well which uses the latest Spring Security 3.1
Spring Security 3.1 - Implement UserDetailsService with Spring Data JPA

What is Spring Security?

Spring Security provides comprehensive security services for J2EE-based enterprise software applications. There is a particular emphasis on supporting projects built using The Spring Framework, which is the leading J2EE solution for enterprise software development. If you're not using Spring for developing enterprise applications, we warmly encourage you to take a closer look at it. Some familiarity with Spring - and in particular dependency injection principles - will help you get up to speed with Spring Security more easily.

Source: http://static.springsource.org/spring-security/site/docs/3.1.x/reference/introduction.html#what-is-acegi-security

Let's start by showing the contents of our modified spring-security.xml file

spring-security.xml

Half of this configuration file is still the same as with our previous spring-security.xml.

Here are the notable changes:
1. The auto-config tag is now set to false.


This is set to false so that we can assign custom filters.

2. The form-login tag and its attributes are removed.


This element had been removed because we will provide a custom authentication manager.

3. The child elements of authentication-manager are removed.


The child elements had been removed because we will provide a custom authentication manager.

4. We declared a custom AuthenticationEntryPoint bean and reference that in the http tag:

5. We declared a custom-filter tag inside the http tag:

The FORM_LOGIN_FILTER is an alias among the Spring-Security filter chain. For a thorough treatment of this subject, please read Spring Security Reference for Security Namespace Configuration and Table 2.1. Standard Filter Aliases and Ordering for the actual ordering and filter classes associated for each alias.

6. Declare the authenticationFilter bean:

UsernamePasswordAuthenticationFilter is the default class for the FORM_LOGIN_FILTER alias. We're reusing this implementation, and provide our extension points in its properties.

7. Declare the required bean properties:

CustomAuthenticationManager is our custom authentication manager. SimpleUrlAuthenticationFailureHandler and SimpleUrlAuthenticationSuccessHandler are standard classes uses by the UsernamePasswordAuthenticationFilter. We declared these two beans so that we can assign a custom failure url and a default target url. Remember we have removed the form-login tag which provides a convenient way of declaring special urls. They don't exist now so must provide it.

Let's examine the contents of CustomAuthenticationManager:

CustomAuthenticationManager

CustomAuthenticationManager implements the authenticate method to provide a custom authentication process. To retrieve the users from the database, it communicates through the UserDAO. Then it compares the results retrieved from the database to the entries received from the login form. If the username and password are the same, we throw a BadCredentialsException.

Here's another filter.

If you examine closely the spring-security.xml file, I've declared another filter named BlacklistFilter:

This filter is executed before the alias FILTER_SECURITY_INTERCEPTOR. This filter will deny web access if the username is equal to 'mike'. Sorry mike :)

BlacklistFilter

Please read the comments within the class for an explanation of this filter.

Besides the files we discussed here, everything else is still the same as with the previous tutorial Spring Security - MVC Integration Tutorial (Part 2)

Our application is now finished. We managed to setup a simple Spring 3 MVC application with authentication and authorization support using Spring Security 3. In addition, we've managed to create a custom authentication manager. We've also leveraged Spring's MVC programming model via annotation.

The best way to learn further is to try the actual application.

Download the project
You can access the project site at Google's Project Hosting at http://code.google.com/p/spring3-security-mvc-integration-tutorial/

You can download the project as a Maven build. Look for the spring-security-custom-auth-manager.zip in the Download sections.

You can run the project directly using an embedded server via Maven.
For Tomcat: mvn tomcat:run
For Jetty: mvn jetty:run

If you want to learn more about Spring MVC and Spring Security, feel free to read my other tutorials in the Tutorials section.

References:
Spring Security 3.1.0.M2 API
Spring Security Reference Documentation

---

Share the joy: blogger tutorials Social Bookmarking Blogger Widget I'm reading: Spring Security 3 - MVC Integration: Using A Custom Authentication Manager ~

Subscribe by reader Subscribe by email Share