模型实验 fix bug

recommend-server-service/src/main/java/com/tzld/piaoquan/recommend/server/service/rank/RankRouter.java

@@ -17,6 +17,9 @@ public class RankRouter {
     private RankStrategy4Density rankStrategy4Density;
     public RankResult rank(RankParam param) {
         String abCode = param.getAbCode();
+        if (abCode == null) {
+            return rankService.rank(param);
+        }
         switch (abCode){
             case "60101":
                 return rankStrategy4RankModel.rank(param);