增加断言

@@ -168,6 +168,7 @@ public class SearchExplainerService {
     }
 
     private SearchFieldResult showSingleField(FieldWithBoost fieldWithBoost, Object fieldValue, FieldDesc fieldDesc) throws Exception {
+        Assert.notNull(fieldDesc, "for " + fieldWithBoost.fieldName);
         SearchFieldResult searchFieldResult = new SearchFieldResult();
         searchFieldResult.setFieldName(fieldWithBoost.fieldName);
         searchFieldResult.setBoost(fieldWithBoost.boost);