What is the role of the ActionSupport class in Struts2?

The ActionSupport class is a foundational class in the Struts2 framework that offers commonly used methods and attributes to simplify the process of writing Action classes and handling requests.

The purpose of the ActionSupport class includes:

1. ActionSupport class inherits from the Action class and includes commonly used attributes and methods such as getter and setter methods, which are used for handling and retrieving request parameters and result data.
2. The support for internationalization is provided: The ActionSupport class offers the getText() method to access text information defined in internationalization resource files, facilitating internationalization handling.
3. Support for validation is provided: The ActionSupport class offers various validation methods, such as validate() method to verify request parameters, and addActionError() and addFieldError() methods to add error messages and field error messages, making it convenient for parameter validation and error handling.
4. Support for messages is provided: The ActionSupport class provides the addActionMessage() and addActionMessageKey() methods for adding general messages and message keys, making it easy to display informational messages on the page.
5. The support for result processing is provided: The ActionSupport class offers commonly used result processing methods, such as constants like SUCCESS, ERROR, and INPUT, which are used to specify different ways of handling results.

By inheriting the ActionSupport class, it becomes easier to write Action classes, improve code readability and maintainability, and facilitate request handling, parameter validation, and result returning.