Update: web.xml and generated files

web/WEB-INF/classes/com/demo/action/HelloAction.java

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+package com.demo.action;
+
+import com.opensymphony.xwork2.ActionSupport;
+
+/**
+ * Hello World 示例 Action
+ * 展示 Struts2 最基础的 Action 写法
+ * 
+ * ActionSupport 提供了：
+ * - validate() 方法用于表单验证
+ * - getText() 方法用于国际化
+ * - addActionError()/addFieldError() 用于错误消息
+ */
+public class HelloAction extends ActionSupport {
+    
+    private String name;
+    private String message;
+    
+    @Override
+    public String execute() throws Exception {
+        // 业务逻辑
+        if (name == null || name.trim().isEmpty()) {
+            name = "World";
+        }
+        message = "Hello, " + name + "! 欢迎学习 Struts2!";
+        return SUCCESS;
+    }
+    
+    // Getter/Setter (Struts2 需要这些来获取/设置参数)
+    public String getName() { return name; }
+    public void setName(String name) { this.name = name; }
+    public String getMessage() { return message; }
+    public void setMessage(String message) { this.message = message; }
+}

web/WEB-INF/classes/com/demo/action/LoginAction.java

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+package com.demo.action;
+
+import com.opensymphony.xwork2.ActionSupport;
+
+/**
+ * 用户登录 Action
+ * 展示：
+ * - 表单参数接收
+ * - 数据验证
+ * - Session 使用
+ * - 返回不同结果
+ */
+public class LoginAction extends ActionSupport {
+    
+    private String username;
+    private String password;
+    
+    @Override
+    public String execute() throws Exception {
+        // 模拟登录验证
+        if ("admin".equals(username) && "123456".equals(password)) {
+            // 登录成功，设置 session
+            return SUCCESS;
+        } else if (username != null && !username.isEmpty()) {
+            // 登录失败
+            addActionError("用户名或密码错误!");
+            return INPUT;
+        }
+        return INPUT;
+    }
+    
+    // 表单验证
+    @Override
+    public void validate() {
+        if (username == null || username.trim().length() < 3) {
+            addFieldError("username", "用户名至少3个字符");
+        }
+        if (password == null || password.length() < 6) {
+            addFieldError("password", "密码至少6个字符");
+        }
+    }
+    
+    public String getUsername() { return username; }
+    public void setUsername(String username) { this.username = username; }
+    public String getPassword() { return password; }
+    public void setPassword(String password) { this.password = password; }
+}

web/WEB-INF/classes/com/demo/model/User.java

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+package com.demo.model;
+
+/**
+ * 用户模型
+ * 展示 Struts2 的 ModelDriven 和 Bean 封装
+ */
+public class User {
+    private Long id;
+    private String username;
+    private String email;
+    private String phone;
+    
+    public User() {}
+    
+    public User(Long id, String username, String email) {
+        this.id = id;
+        this.username = username;
+        this.email = email;
+    }
+    
+    // Getters and Setters
+    public Long getId() { return id; }
+    public void setId(Long id) { this.id = id; }
+    public String getUsername() { return username; }
+    public void setUsername(String username) { this.username = username; }
+    public String getEmail() { return email; }
+    public void setEmail(String email) { this.email = email; }
+    public String getPhone() { return phone; }
+    public void setPhone(String phone) { this.phone = phone; }
+}

web/WEB-INF/classes/struts.xml

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+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE struts PUBLIC
+    "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
+    "http://struts.apache.org/dtds/struts-2.5.dtd">
+
+<struts>
+    <!-- 开发模式 - 修改配置后自动reload -->
+    <constant name="struts.devMode" value="true"/>
+    <constant name="struts.enable.DynamicMethodInvocation" value="true"/>
+    
+    <!-- 编码设置 -->
+    <constant name="struts.i18n.encoding" value="UTF-8"/>
+
+    <!-- ==================== 示例包定义 ==================== -->
+    <package name="default" namespace="/" extends="struts-default">
+        
+        <!-- 首页 -->
+        <action name="index">
+            <result>/index.jsp</result>
+        </action>
+        
+        <!-- Hello World 示例 -->
+        <action name="hello" class="com.demo.action.HelloAction" method="execute">
+            <result>/hello.jsp</result>
+        </action>
+        
+        <!-- 用户登录示例 -->
+        <action name="login" class="com.demo.action.LoginAction" method="execute">
+            <result name="success">/user/success.jsp</result>
+            <result name="input">/user/login.jsp</result>
+        </action>
+        
+        <!-- 用户表单提交 -->
+        <action name="submitUser" class="com.demo.action.UserAction" method="submit">
+            <result name="success">/user/success.jsp</result>
+            <result name="input">/user/form.jsp</result>
+        </action>
+        
+        <!-- 文件上传示例 -->
+        <action name="upload" class="com.demo.action.FileUploadAction" method="execute">
+            <result name="success">/upload/success.jsp</result>
+            <result name="input">/upload/index.jsp</result>
+        </action>
+        
+        <!-- AJAX 示例 -->
+        <action name="ajax" class="com.demo.action.AjaxAction" method="execute">
+            <result type="json"/>
+        </action>
+        
+        <!-- 验证示例 -->
+        <action name="validate" class="com.demo.action.ValidationAction" method="execute">
+            <result name="success">/validation/success.jsp</result>
+            <result name="input">/validation/form.jsp</result>
+        </action>
+        
+    </package>
+    
+    <!-- REST 风格示例 -->
+    <package name="rest" namespace="/api" extends="struts-default">
+        <action name="users" class="com.demo.action.rest.UserRestAction">
+            <result type="json"/>
+        </action>
+    </package>
+
+</struts>