fix: 改进登录流程的错误处理和日志

- 添加详细的登录日志输出
- 获取openId失败时返回错误而非创建guest用户
- 避免重复创建用户账号

src/main/java/xuan/controller/UserController.java

@@ -39,6 +39,11 @@ public class UserController {
             String username = params.get("nickname") != null ? params.get("nickname").toString() : "微信用户";
             String avatarUrl = params.get("avatarUrl") != null ? params.get("avatarUrl").toString() : "";
             
+            System.out.println("=== 登录请求 ===");
+            System.out.println("code: " + code);
+            System.out.println("appId: " + appId);
+            System.out.println("appSecret: " + (appSecret != null ? "已配置" : "未配置"));
+            
             String openId = null;
             
             if (code != null && !code.isEmpty() && appId != null && !appId.isEmpty() && appSecret != null && !appSecret.isEmpty()) {
@@ -47,25 +52,39 @@ public class UserController {
                     appId, appSecret, code
                 );
                 
+                System.out.println("调用微信API: " + url);
+                
                 try {
                     RestTemplate restTemplate = new RestTemplate();
                     @SuppressWarnings("unchecked")
                     Map<String, Object> wxResult = restTemplate.getForObject(url, Map.class);
                     
+                    System.out.println("微信API返回: " + wxResult);
+                    
                     if (wxResult != null && wxResult.containsKey("openid")) {
                         openId = (String) wxResult.get("openid");
+                        System.out.println("获取到openId: " + openId);
+                    } else if (wxResult != null) {
+                        System.err.println("微信API返回错误: " + wxResult.get("errmsg") + ", errcode: " + wxResult.get("errcode"));
                     }
                 } catch (Exception e) {
                     System.err.println("调用微信API失败: " + e.getMessage());
+                    e.printStackTrace();
                 }
+            } else {
+                System.err.println("登录参数不完整: code=" + code + ", appId=" + appId + ", appSecret=" + (appSecret != null ? "有" : "无"));
             }
             
             if (openId == null || openId.isEmpty()) {
-                openId = "guest_" + System.currentTimeMillis();
+                result.put("success", false);
+                result.put("error", "获取用户身份失败，请重试");
+                return result;
             }
             
             UserInfo user = userInfoService.loginOrRegister(openId, username, avatarUrl);
             
+            System.out.println("登录成功: userId=" + user.getUserId() + ", openId=" + user.getOpenId());
+            
             Map<String, Object> data = new HashMap<>();
             data.put("id", user.getId());
             data.put("userId", user.getUserId());
@@ -81,6 +100,8 @@ public class UserController {
             result.put("success", true);
             result.put("data", data);
         } catch (Exception e) {
+            System.err.println("登录异常: " + e.getMessage());
+            e.printStackTrace();
             result.put("success", false);
             result.put("error", e.getMessage());
         }