feat: Spring Boot示例项目

- 基础Spring Boot配置
- Docker支持

src/main/java/com/example/demo/model/UserEvent.java

@@ -0,0 +1,51 @@
+package com.example.demo.model;
+
+import java.time.LocalDateTime;
+
+/**
+ * 用户事件 - 演示 Spring 事件机制
+ * 
+ * 学习点：
+ * - ApplicationEvent 基类
+ * - 事件驱动架构
+ * - 观察者模式
+ */
+public class UserEvent {
+    
+    public enum Type {
+        CREATED,    // 用户创建
+        UPDATED,    // 用户更新
+        DELETED,    // 用户删除
+        LOGIN       // 用户登录
+    }
+    
+    private Type type;
+    private Long userId;
+    private String userName;
+    private LocalDateTime timestamp;
+    private String detail;
+    
+    public UserEvent() {
+        this.timestamp = LocalDateTime.now();
+    }
+    
+    public UserEvent(Type type, Long userId, String userName, String detail) {
+        this.type = type;
+        this.userId = userId;
+        this.userName = userName;
+        this.detail = detail;
+        this.timestamp = LocalDateTime.now();
+    }
+    
+    // Getters and Setters
+    public Type getType() { return type; }
+    public void setType(Type type) { this.type = type; }
+    public Long getUserId() { return userId; }
+    public void setUserId(Long userId) { this.userId = userId; }
+    public String getUserName() { return userName; }
+    public void setUserName(String userName) { this.userName = userName; }
+    public LocalDateTime getTimestamp() { return timestamp; }
+    public void setTimestamp(LocalDateTime timestamp) { this.timestamp = timestamp; }
+    public String getDetail() { return detail; }
+    public void setDetail(String detail) { this.detail = detail; }
+}