Struts 2 And Spring Frameworks Together
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This document discusses using the Struts 2 and Spring frameworks together. It provides code examples of integrating Spring into Struts 2 applications to manage dependencies and leverage Spring features like AOP and Spring JDBC. Examples are given of configuring Struts 2 actions as Spring beans and managing dependencies through Spring rather than direct instantiation. Benefits include reduced coupling, centralized dependency management, and ability to take advantage of Spring capabilities not in Struts 2 like transaction management.
Struts 2 And Spring Frameworks Together
- 1. Using Struts 2 and Spring Frameworks Together Bruce Phillips University of Kansas March 2009 Presentation and code examples available at http://www.brucephillips.name/spring
- 2. References Spring Framework - http://www.springsource.org/documentation Spring Community Forums - http://forum.springsource.org/ Introduction to the Spring Framework 2.5 - http://www.theserverside.com/tt/articles/article.ts s?l=IntrotoSpring25 Spring in Action, 2nd Edition, Manning Publishing, August 2007 Pro Spring 2.5, Apress Publishing, August 2008 Struts 2 Framework - http://struts.apache.org 2
- 3. References Using Struts 2 and Spring Frameworks Together, Bruce Phillips Blog - http://www.brucephillips.name/blog/index.cfm/2008/10/17/Usi ng-Struts-2-and-Spring-Frameworks-Together Introduction to the Java Spring Framework, http://www.brucephillips.name/blog/index.cfm/2009/1/29/Intr oduction-to-the-Java-Spring-Framework Struts 2 In Practice, Manning Publishing, http://www.manning.com/wannemacher/ Apache Struts 2 Documentation, Spring Plugin - http://struts.apache.org/2.x/docs/spring-plugin.html Struts User Forum - http://www.nabble.com/Struts---User- f206.html Maven - http://maven.apache.org/ Maven - http://books.sonatype.com/maven-book/index.html 3
- 4. Spring and Struts 2 Frameworks Introduction to the Java Spring Framework ◦ http://www.brucephillips.name/blog/index.cfm/ 2009/1/29/Introduction-to-the-Java-Spring- Framework Introduction to The Struts 2 Java Web Application Framework ◦ http://www.brucephillips.name/blog/index.cfm/ 2008/10/7/Introduction-toThe-Struts-2-Java- Web-Application-Framework 4
- 5. Advantages of Using Spring and Struts 2 Together Leverage the strengths of both frameworks Spring ◦ Dependency management ◦ Aspect-Oriented Programming (AOP) ◦ Spring JDBC Struts 2 ◦ Simplifies implementing the model, view, controller (MVC) pattern in a web application 5
- 6. Example Applications Struts2_Spring_Example ◦ Simple Struts 2 application that uses Spring to manage dependencies ContactsWebApp ◦ More complicated Struts 2 application that uses Spring to manage dependencies, implement cross-cutting (AOP) concerns, and interact with a database repository Code and installation instructions at ◦ http://www.brucephillips.name/spring 6
- 7. Classes Depend On Other Classes Developers must “manage” these class dependencies (coupling) Struts ActionSupport Classes CreatePhone CreateContact CreateEmail Service Classes PhoneService ContactService EmailService ContactsWebApp – sampling of class dependencies Persistence Classes PhoneDataAccess ContactDataAccess EmailDataAccess 7
- 8. Struts Without Spring Struts web applications tend to have quite a few “controller” (ActionSupport) classes These “controller” classes call upon other classes to do the work Without Spring must use concrete object instantiation ◦ ContactService contactService = new ContactServiceImpl(); ◦ The same code will be repeated in all the other Struts ActionSupport classes that use a ContactService object Each class is responsible for managing its dependencies ◦ More difficult to configure, maintain, and change 8
- 9. Struts With Spring Use Spring to manage dependencies ◦ Dependencies are specified and managed in one place ◦ Much easier to change dependencies ◦ Most dependencies can be “auto-wired” Use the other benefits Spring provides ◦ Aspect Oriented Programming (AOP) ◦ Spring JDBC ◦ Transaction Management 9
- 10. Jars Required See Struts2_Spring_Example application ◦ jars are under Referenced Libraries ◦ spring.jar is needed to use Spring capabilities ◦ struts2-spring-plugin-2.1.6.jar is needed so that Struts 2 can use Spring 10
- 11. How To Integrate Spring Into Struts Changes to web.xml ◦ Add ContextLoaderListener and RequestContextListener to web.xml Add applicationContext.xml ◦ Under WEB-INF ◦ Spring configuration and bean definitions 11
- 12. Use Spring to Manage Dependencies There are two different ways to have Spring manage the dependencies in a Struts application ◦ Configure your actions as Spring beans applicationContext.xml ◦ Configure your actions in struts.xml applicationContext_alternate.xml ◦ In both cases use Spring to manage dependencies between your ActionSupport classes and other classes 12
- 13. Struts2_Spring_Example Register class is a Struts ActionSupport class ◦ Register class depends upon a PersonService class Option 1 use Spring to create and manage the Register objects See applicationContext.xml Note the id value for the Register bean Register class requires a PersonService object and Spring will manage this dependency In struts.xml create the action node but for the class value use the id value specified in applicationContext.xml 13
- 14. Struts2_Spring_Example Option 2 ◦ See struts_alternate.xml Create action node as usual by specifying the complete class for the class attribute ◦ See applicatonContext_alternate.xml Just create those beans for classes that are NOT Struts ActionSupport classes ◦ Spring will manage any dependencies for the ActionSupport classes Register class depends on PersonService class Before a Register object is provided to the application, Spring will pass a PersonService object to class Register’s setPersonService method 14
- 15. Struts 2 and Spring Configuration Options How both option 1 and option 2 manage dependencies can be configured to bypass the defaults ◦ See chapter 3 Struts 2 In Practice ◦ See Struts 2 Spring plugin documentation at: http://struts.apache.org/2.x/docs/spring-plugin.html 15
- 16. ContactsWebApp Very simple contacts manager Web application that uses Struts 2 and Spring ◦ Database is embedded Derby Uses Struts to manage ActionSupport classes (option 2) and Spring to: ◦ Manage dependencies ◦ Implement cross-cutting concerns such as logging, performance timing ◦ Interact with database repository (Spring JDBC) 16
- 17. ContactsWebApp – FindContact and its dependencies ActionSupport FindContact Class Service ContactSearchService Layer ContactDataAccess Persistence Layer PhoneDataAccess EmailDataAccess PersonDataAccess DataSource 17
- 18. ContactsWebApp – struts.xml and applicationContext.xml struts.xml ◦ Action nodes specify complete class value ◦ For example FindContact Note class FindContact needs a ContactSearchService object and has a public setContactSearchService method applicationContext.xml ◦ Spring configuration ◦ Create Spring beans for all non- ActionSupport classes that are used by the ActionSupport class 18
- 19. Struts 2 – Spring Interaction applicationContext.xml Spring will provide any objects needed by the ActionSupport classes automatically ◦ Autowire “by name” ◦ For example FindContacts property contactSearchService will get a value because Spring will call the setContactSearchService method and pass it a contactSearchService object Spring is also managing dependencies for the other classes ◦ For example see contactSearchService, contactDataAccess and personDataAccess beans ◦ Be sure to specify scope=“request” 19
- 20. Spring AOP Can use Spring AOP just as we did in the non-Struts 2 Contact application Same configuration in the Struts 2 project’s applicationContext.xml as we had in the Contact (non-web) project’s applicationContext_DB_Repository.xml See package edu.ku.si.contact.advice 20
- 21. AOP Example - Exception Logging Need to specify where to apply the advice ◦ See ExceptionLogging class PointCut definition ◦ Don’t need to apply advice to the ActionSupport classes because they won’t be the originator of any Exceptions Rename c:/derby/contactsDB to c:/derby/tcontactsDB Run ContactsWebApp 21
- 22. Spring JDBC Can use Spring JDBC as we did in the Contact (non-Struts 2) application See package edu.ku.si.contact.data The data access classes extend Spring JDBC’s SimpleJdbcDaoSupport ◦ See PersonDataAccess ◦ Much simpler to query database and process results ◦ Note Spring JDBC will manage opening and closing connections, handling exceptions, etc. 22
- 23. Data Source Management The data access classes need a Data Source object ◦ See applicationContext.xml ◦ Note no scope is specified for the dataSource bean By extending SimpleJdbcDaoSupport the data access classes inherit the setDataSource method which Spring uses to inject the data source object To use connection pooling see notes in applicationContext.xml 23
- 24. Why Use Spring With Struts 2? Significantly reduces coupling between classes Central management of dependencies Applications are easier to maintain and change Leverage Spring features that Struts 2 doesn’t provide ◦ Aspect-oriented programming ◦ Spring JDBC 24