Update: web.xml and generated files

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

@@ -0,0 +1,34 @@
+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; }
+}