In-depth exploration of the working principle of the Struts2 framework

Struts2 is a Java Web application framework that adopts the MVC (Model-View-Controller) design pattern for rapid development and management of Web applications. Through in-depth study of the internal mechanism of the Struts2 framework, you can better understand its working principle and deepen your understanding of the framework. This article will explore the internal mechanism of the Struts2 framework and illustrate it with specific code examples to help readers better understand the operating principle of Struts2.

1. Interceptors

In the Struts2 framework, interceptors are components that play a key role and are used to process user requests. When a user sends a request, the request is processed sequentially by a stack of interceptors, with each interceptor responsible for performing a specific operation. Developers can customize interceptors and add them to the interceptor stack to implement specific functions.

The following is a simple interceptor example showing how to create a custom interceptor:

package com.example.interceptor;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;

public class CustomInterceptor implements Interceptor {

    @Override
    public void destroy() {
        // 销毁拦截器
    }

    @Override
    public void init() {
        // 初始化拦截器
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        // 在此处编写自定义的拦截逻辑
        return invocation.invoke();
    }
}

2. Model-Driven

In Struts2 In the framework, model driver allows data models to be bound to Action classes, making data processing more convenient. Through model driving, data can be encapsulated and transferred, simplifying the development process.

The following is a simple example that shows how to use model-driven processing of form data in Struts2:

package com.example.action;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction extends ActionSupport {

    private User user = new User();

    public String execute() {
        // 在这里可以对用户提交的数据进行处理
        return SUCCESS;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }
}

3. Result Views

In the Struts2 framework The result view is used to display the results of user requests, which can be JSP pages, JSON data or data in other formats. Developers can configure different result views to achieve different display effects.

The following is an example showing how to configure a JSP page as a result view in Struts2:

<result name="success" type="dispatcher">/WEB-INF/view/success.jsp</result>

In this example, when the Action is executed successfully, it will jump to /WEB -INF/view/success.jsp page for display.

Conclusion

By conducting in-depth research on the internal mechanism of the Struts2 framework, we can better understand its operating principles and be able to flexibly apply the various functions provided by the framework. I hope that the code examples provided in this article can help readers better understand the Struts2 framework and play a role in practical applications.

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