Struts2 Black Book PDF - A Comprehensive and Practical Guide for Java Web Development
Struts2 Black Book: A Comprehensive Guide for Java Web Developers
If you are a Java web developer who wants to create powerful, scalable, and maintainable web applications using the popular Struts2 framework, then this article is for you. In this article, you will learn everything you need to know about Struts2, from its features and architecture to its practical usage and customization. You will also discover how to download a free PDF copy of the Struts2 Black Book, a comprehensive reference book that covers all aspects of Struts2 development.
struts2 black book pdf free download
What is Struts2?
Struts2 is an open source web application framework that helps you create dynamic, interactive, and user-friendly web pages using Java technologies. It is based on the Model-View-Controller (MVC) design pattern, which separates the business logic, presentation logic, and data access logic of your application. This way, you can achieve a high degree of modularity, reusability, and testability in your code.
Struts2 is a successor of the original Struts framework, which was one of the first and most widely used Java web frameworks. However, Struts2 is not a direct continuation of Struts1, but rather a completely redesigned and rewritten framework that incorporates many improvements and new features. Some of the main differences between Struts1 and Struts2 are:
Struts2 uses plain Java objects (POJOs) as action classes, instead of extending a base class or implementing an interface. This gives you more flexibility and control over your actions.
Struts2 uses a powerful expression language called Object Graph Navigation Language (OGNL), which allows you to access and manipulate data in your application without writing any Java code.
Struts2 supports a variety of view technologies, such as JSP, FreeMarker, Velocity, Tiles 2, etc., which you can use to create dynamic and rich user interfaces.
Struts2 provides a set of generic and UI tags that simplify the development of web pages. You can also create your own custom tags using simple XML configuration.
Struts2 has a flexible and extensible interceptor mechanism that allows you to intercept and modify requests and responses before and after they reach your actions. You can also create your own custom interceptors using simple Java classes.
Struts2 has a built-in validation framework that allows you to validate user input using XML configuration or annotations. You can also use custom validators or integrate with other validation frameworks such as Hibernate Validator.
Struts2 supports internationalization and localization using resource bundles and message keys. You can also use different locales and time zones for different users.
Struts2 has a plugin architecture that allows you to extend its functionality with additional features. There are many plugins available for Struts2 that provide support for AJAX, security, file upload, RESTful web services, etc.
Features and benefits of Struts2
Struts2 is a mature, stable, and widely used web framework that offers many features and benefits for Java web developers. Some of the main advantages of using Struts2 are:
It is easy to learn and use, as it follows the standard Java conventions and best practices. It also has a clear and consistent documentation and a large and active community of users and developers.
It is highly configurable and customizable, as it allows you to change almost every aspect of its behavior using XML files, annotations, or properties. You can also override or replace any component of the framework with your own implementation.
It is scalable and performant, as it uses a lightweight and stateless architecture that minimizes the memory consumption and maximizes the throughput of your application. It also supports caching, pooling, and clustering techniques to improve the performance and reliability of your application.
It is testable and debuggable, as it provides various tools and mechanisms to help you test and debug your application. You can use JUnit, TestNG, Selenium, or other testing frameworks to write unit tests, integration tests, or functional tests for your application. You can also use logging, profiling, or monitoring tools to track and analyze the behavior and performance of your application.
It is compatible and interoperable, as it supports the latest Java standards and technologies, such as Servlets, JSPs, JavaBeans, EL, JSTL, etc. It also integrates well with other frameworks and libraries, such as Spring, Hibernate, EJB, JSF, etc.
Architecture and components of Struts2
The architecture of Struts2 is based on the MVC design pattern, which divides your application into three layers: model, view, and controller. The model layer represents the data and business logic of your application. The view layer represents the user interface of your application. The controller layer handles the requests from the user and coordinates the interaction between the model and the view.
The following diagram shows the main components of Struts2 and how they interact with each other:
![Struts2 Architecture](https://i.imgur.com/0a9xqQg.png) The main components of Struts2 are:
Action: An action is a POJO that performs a specific task in response to a user request. It usually contains some properties that store the input or output data of the action, and some methods that execute the business logic of the action. An action can also return a result that determines what view should be rendered after the action is executed.
Interceptor: An interceptor is a class that intercepts a request or a response before or after it reaches an action. It can perform some common tasks such as logging, authentication, authorization, validation, etc. Interceptors can be chained together to form an interceptor stack that applies to one or more actions.
Result: A result is an object that renders a view after an action is executed. It can be a simple string that represents a logical name of a view (such as "success" or "error"), or a complex object that contains some parameters for rendering a view (such as a file name, a content type, etc.). Struts2 supports different types of results for different view technologies, such as JSPs, FreeMarker templates, Velocity templates, Tiles definitions, etc.
ValueStack: A value stack is an object that stores the data that is used by the actions and the views. It is composed of a stack of objects (such as actions, models, etc.) that can be accessed using OGNL expressions. The value stack is created for each request and is available in both actions and views.
ActionContext: An action context is an object that stores the context information of a request. It contains some attributes that store the references to other objects such as the value stack, the session map, the application map, the parameters map, etc. The action context is also created for each request and is available in both actions and views.
ActionInvocation: An action invocation is an object that represents the execution of an action. It contains some methods that allow you to invoke an action, get or set its result, get its action context or value stack, etc. The action invocation is also created for each request and is passed to each interceptor in the interceptor stack.
ActionProxy: An action proxy is an object that encapsulates an action invocation. It contains some methods that allow you to get or set some properties of an action invocation, such as its action name, namespace, method name, result code, etc. The action proxy is also created for each request and is used by the controller layer to execute an action.