feat(user):通过完成用户检索功能，继续确定项目的基本代码结构。

cache/search.go

@@ -1,11 +1,16 @@
 package cache
 
 import (
+	"electricity_bill_calc/logger"
 	"fmt"
 	"strings"
 	"time"
+
+	"go.uber.org/zap"
 )
 
+var log = logger.Named("Cache")
+
 func assembleSearchKey(entityName string, additional ...string) string {
 	var keys = make([]string, 0)
 	keys = append(keys, strings.ToUpper(entityName))
@@ -70,6 +75,10 @@ func RetrievePagedSearch[T any](entityName string, conditions ...string) (*T, in
 	if err != nil {
 		return nil, -1, err
 	}
+	if instance == nil || count == nil {
+		log.Warn("检索结果或者检索总数为空。", zap.String("searchKey", searchKey), zap.String("countKey", countKey))
+		return nil, -1, nil
+	}
 	return instance, count.Count, nil
 }