description KeyedGroupSumFuntion.java

wangdxh · Mar 2, 2020 · 6b288df · 6b288df
1 parent 062dafc
commit 6b288df
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/main/java/com/didichuxing/aggregation/functions/KeyedGroupSumFuntion.java b/src/main/java/com/didichuxing/aggregation/functions/KeyedGroupSumFuntion.java
@@ -14,7 +14,7 @@
 import org.apache.flink.util.Collector;
 
 /**
- * 目的：自定义实现keyBy()后的sum操作，利用KeyedState，实现每个Subtask中每个组的sum
+ * 目的：自定义实现keyBy()后的sum操作，利用KeyedState，实现每个Subtask中每个组的sum。其实可以实现远不止sum的功能，类似scala中的mapWithState
  * 输入：spark hadoop scala java python js matlab php go spark hadoop java spark
  * 输出：2> (python,1)
  *      4> (hadoop,1)