Java Language - 196 - Apache Struts

Web Frameworks and Libraries – Apache Struts

Apache Struts is an open-source web application framework for building Java-based web applications. It follows the Model-View-Controller (MVC) architectural pattern and provides a set of tools and components for developing robust and scalable web applications. In this article, we will explore the key features and benefits of Apache Struts and provide code examples to illustrate its usage.

1. Introduction to Apache Struts

Apache Struts is widely used for developing web applications in Java. It promotes the separation of concerns by dividing the application into three key components:

1.1. Model

The model represents the application’s data and business logic. It manages the interaction with the database and performs various operations on the data.

1.2. View

The view is responsible for rendering the user interface. It presents the data to the user and collects user input. Apache Struts uses JavaServer Pages (JSP) for creating dynamic views.

1.3. Controller

The controller handles the flow of the application. It receives user requests, processes them, and interacts with the model to update the data. Apache Struts uses actions and configuration files to manage the control flow.

2. Key Features of Apache Struts

Apache Struts offers a range of features that make it a popular choice for web application development:

2.1. MVC Architecture

Struts enforces a clean separation of concerns, making it easier to manage and maintain code. This separation simplifies development, testing, and collaboration among developers.

2.2. Reusable Components

Struts provides reusable components like form beans and custom tags that simplify the development of web forms and user interfaces. These components reduce code duplication and enhance productivity.

2.3. Validation Framework

Apache Struts includes a validation framework that allows developers to define and enforce data validation rules. This helps ensure that data entered by users is accurate and secure.

2.4. Configuration Options

Struts allows developers to configure their applications using XML files, providing flexibility and making it easy to modify application behavior without changing code. This configuration-driven approach simplifies application management.

3. Setting Up an Apache Struts Project

To get started with Apache Struts, you need to set up a Struts project in your preferred integrated development environment (IDE). You also need to include the Struts library in your project. Once the project is set up, you can begin writing Struts code.

4. Building a Simple Struts Application

Let’s create a basic Apache Struts application that displays a “Hello, Struts!” message in a web browser. First, define an action class:

public class HelloWorldAction extends Action {
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response) {
        return mapping.findForward("success");
    }
}

In this code, we create an action class that extends Action. The execute method is called when the action is invoked. In this case, it returns a forward named “success,” which is defined in the Struts configuration file.

5. Defining a Struts Configuration

In the Struts configuration file (struts-config.xml), we define the action and its mapping to a forward:

<action path="/helloWorld" type="com.example.HelloWorldAction" name="helloForm" scope="request" validate="true" 
      input="/hello.jsp" parameter="method">
    <forward name="success" path="/success.jsp" />
</action>

This configuration specifies the mapping of the “/helloWorld” URL to the HelloWorldAction class. If the action is successful, it forwards to the “success” page.

6. Creating JSP Pages

We also need to create the JSP pages for our application. Here’s a simple “hello.jsp” page:

<html>
  <head>
    <title>Hello, Struts!</title>
  </head>
  <body>
    <form action="helloWorld.do" method="post">
      <input type="submit" value="Say Hello">
    </form>
  </body>
</html>

And the “success.jsp” page:

<html>
  <head>
    <title>Hello, Struts!</title>
  </head>
  <body>
    <h1>Hello, Struts!</h1>
  </body>
</html>

7. Running the Struts Application

To run your Apache Struts application, you can deploy it on a web server or an application server. Once deployed, you can access your application in a web browser by navigating to the appropriate URL. In this case, it would be “http://yourserver/helloWorld.do”.

8. Building Complex Struts Applications

Apache Struts is well-suited for building complex web applications with multiple pages, forms, and interactive elements. It offers features like tag libraries for JSP, localization support, and powerful validation mechanisms to streamline development.

9. Conclusion

Apache Struts is a reliable and feature-rich framework for building Java-based web applications. Its adherence to the MVC pattern, reusable components, and strong validation capabilities make it an excellent choice for developing scalable and maintainable web applications. Whether you’re building a simple web form or a complex enterprise application, Apache Struts can help you achieve your goals efficiently.

Java Language – 196 – Apache Struts