overlay lazy dilution

src/main/java/com/gct/edge/actuator/service/impl/DiagnoseServiceImpl.java

@@ -260,7 +260,7 @@ public class DiagnoseServiceImpl extends ServicePlusImpl<DiagnoseResultRealTimeM
                 }
             }
             JSONObject res = getOverlayObj(dilutionResult);
-            res.put("thisPagefirstDate",prePageLastDate);
+            res.put("thisPagefirstDate",Objects.isNull(prePageLastDate)?beginDate:prePageLastDate);
             res.put("thisPagelastDate",dilutionResult.isEmpty()?null:dilutionResult.get(dilutionResult.size()-1).getProTime().format(df));
             return res;
         }