Add configuration to control whether to write null value in JSON serialization in aggregation #283

fizz-common/src/main/java/we/util/MapUtil.java

@@ -358,6 +358,8 @@ public class MapUtil {
 					}
 					return newValue;
 				});
+			} else {
+				target.put(key, value);
 			}
 		});
 		return target;