Update: web.xml and generated files

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

@@ -0,0 +1,47 @@
+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; }
+}