Introduction and Working of Struts Web Framework

Apache Struts is an open-source web application framework developed by the Apache Software Foundation for building Java-based web applications. It is based on the MVC (Model-View-Controller) architecture, which separates business logic, presentation logic, and user input handling into different components.

• Integrates well with Java EE technologies such as Servlets and JSP.
• Provides centralized request processing through a controller servlet.
• Supports flexible and extensible application design.

Struts Framework Architecture

Shows how a client request flows through the Controller, Model, and View components in the Struts MVC framework.

The diagram illustrates how a request flows through the Struts MVC framework.

Components of Struts Framework

The main components of the Struts framework are:

1. Action Class

An Action class processes user requests and executes business logic.

public class LoginAction extends Action {

    public ActionForward execute(
            ActionMapping mapping,
            ActionForm form,
            HttpServletRequest request,
            HttpServletResponse response)
            throws Exception {

        return mapping.findForward("success");
    }
}

2. ActionForm

ActionForm is used to collect data entered by the user.

public class LoginForm extends ActionForm {

    private String username;
    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }
}

3. JSP Pages

JSP pages are used to display information and collect user input.

<html:form action="/login">
    Username:
    <html:text property="username"/>

    Password:
    <html:password property="password"/>

    <html:submit value="Login"/>
</html:form>

4. Configuration File

The struts-config.xml file defines mappings between requests and action classes.

<action-mappings>
    <action
        path="/login"
        type="com.demo.LoginAction"
        name="LoginForm">

        <forward
            name="success"
            path="/success.jsp"/>
    </action>
</action-mappings>

Working of Struts Framework

The working of Struts can be understood through the following steps:

1. HTTP Request from Client

• A user performs an action such as clicking a link or submitting a form.
• This generates an HTTP Request.

2. Controller (Servlet)

• The Controller acts as the central request handler.
• It receives all incoming requests from clients.

3. struts-config.xml

• This configuration file contains action mappings and navigation rules.
• It tells the controller which action class should handle a particular request.

4. Dispatch to Business Logic

• Based on the configuration, the controller dispatches the request to the appropriate Business Logic component.
• Business logic performs the required operations such as database access, calculations, or validations.

5. Update Model (Application State)

• After processing, the business logic updates the Model.
• The model represents the application's data and current state.

6. Forward to View (JSP)

• The controller forwards the processed request to a JSP View.
• The view retrieves data from the model using tags and JavaBeans.

7. Generate HTTP Response

• The JSP page generates the final HTML output.
• The response is sent back to the client browser as an HTTP Response.

Advantages of Struts Framework

• Follows MVC Architecture: Separates business logic, presentation, and control logic, making applications easier to maintain.
• Improves Code Reusability: Components such as Action classes and JSP pages can be reused across the application.
• Easy Maintenance: Changes in one layer have minimal impact on other layers.
• Built-in Form Validation: Provides validation mechanisms to reduce manual coding.
• Supports Internationalization (i18n): Makes it easier to develop multilingual applications.
• Centralized Request Handling: All requests are managed through a single controller servlet.
• Rich Tag Libraries: Offers custom JSP tags that simplify UI development.