Merge remote-tracking branch 'origin/master'

src/main/java/com/winhc/bigdata/udf/split_json.java

@@ -20,6 +20,9 @@ import static apsara.odps.TypesProtos.Type.Map;
 public class split_json extends UDF {
 
     public String evaluate(String unionJson, String keys) {
+        if(StringUtils.isBlank(unionJson) || StringUtils.isBlank(keys)){
+            return "";
+        }
         Gson gson = new Gson();
         List<Litigant> litigants = gson.fromJson(unionJson, new TypeToken<List<Litigant>>() {
         }.getType());