THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
The example code for this tutorial, Spring_Struts2_Ant or Spring_Struts2_Mvn, is available on Google Code - http://code.google.com/p/struts2-examples/downloads/list
. After downloading and unzipping the file, you'll have a folder named Spring_Struts2_Ant (or Spring_Struts2_Mvn). In that folder will be a README.txt file with instructions on now to build and run the example application.
Introduction
In the execute method of many Struts 2 ActionSupport classes are statements that create objects and then have those objects execute methods that perform needed tasks. Whenever one class creates an object of another class that introduces a dependency between the two classes. The Spring framework makes it easier for the application developer to manage these dependencies and helps makes the application more flexible and maintainable. This tutorial will show you how to use Struts 2 and Spring together to manage the dependencies between your ActionSupport classes and other classes in your application.
This tutorial assumes you understand how to use the Spring framework to manage dependencies between classes. You can learn more about Spring by reading the documentation at http://www.springsource.org/documentation
The Struts 2 user mailing list is an excellent place to get help. If you are having a problem getting the tutorial example applications to work search the Struts 2 mailing list. If you don't find an answer to your problem, post a question on the mailing list.
If you examine the example application for the Struts 2 Themes tutorial you'll see this code in the EditAction ActionSupport class
EditAction Class Hard-Coded Dependency
private EditService editService = new EditServiceInMemory();
The above statement hard-codes a dependency between the EditAction class and the EditServiceInMemory class. This is poor design for two reasons.
- If I need to replace the EditServiceInMemory with another class that implements the EditService interface I'll have to hunt down and replace all statements where I hard-coded the dependency.
- I cannot test EditAction without using the EditServiceInMemory class. I cannot isolate EditAction by using a stub implementation of EditService when writing my test case because the use of EditServiceInMemory is hard-coded.
Spring provides a mechanism to manage dependencies by injecting them at run time. Struts 2 ActionSupport classes--like any other Java class-can be injected with a dependent object by the Spring framework. So instead of having the above code, I would have this statement in EditAction.
EditAction Class Hard-Coded Dependency
private EditService editService ;
At run time the Spring framework will provide an object of a class that implements the EditService interface.