What are the key components of the Struts framework?
The Struts framework, which is a popular open-source framework for building Java web applications, is based on the Model-View-Controller (MVC) design pattern. Here are the key components of the Struts framework:
Action Classes: These are Java classes that handle user requests. Each action class corresponds to a specific user action and contains the business logic to process the request. They extend the Action class provided by Struts.
ActionForm: This is a JavaBean that represents the form data submitted by the user. It is used to encapsulate the data from the user input and is typically validated before being processed by the action class.
ActionMapping: This component maps a specific request to an action class. It defines the relationship between the URL and the action that should be executed.
ActionForward: This is used to define the next view that should be displayed after an action is executed. It can forward the request to another resource, such as a JSP page.
Struts Configuration File (struts-config.xml): This XML file is central to the Struts framework. It contains the configuration for action mappings, form beans, and other settings required by the framework.
View Layer (JSP): Struts typically uses JavaServer Pages (JSP) for the view layer. JSPs are used to present the data to the user and can access the data stored in the ActionForm.
Validation Framework: Struts provides a built-in validation framework that allows developers to define validation rules for ActionForms. This can be done using XML configuration files or annotations.
Interceptors: In later versions of Struts (like Struts 2), interceptors are used to handle cross-cutting concerns such as logging, authentication, and input validation.
Struts Tag Libraries: Struts provides custom JSP tags that simplify the development of the view layer. These tags help in rendering form elements, displaying error messages, and managing the flow of data between the model and the view.
Internationalization (i18n): Struts supports internationalization, allowing developers to create applications that can be easily adapted to different languages and regions.
Plugins: Struts can be extended with plugins to add additional functionality, such as integration with other frameworks or libraries.
These components work together to create a structured and maintainable web application, following the MVC architecture, which separates the application logic, user interface, and data handling.