diff --git a/documentation20/cn/08.connector/01.java/docs.md b/documentation20/cn/08.connector/01.java/docs.md
index 4fc10b542b2e4ad4c9a82bfe0d342e56e1297ba7..ffea252c86b5b3eab41e93685e04dfcccccec879 100644
--- a/documentation20/cn/08.connector/01.java/docs.md
+++ b/documentation20/cn/08.connector/01.java/docs.md
@@ -361,6 +361,7 @@ public void setShort(int columnIndex, ArrayList<Short> list) throws SQLException
 public void setString(int columnIndex, ArrayList<String> list, int size) throws SQLException
 public void setNString(int columnIndex, ArrayList<String> list, int size) throws SQLException
 ```
+其中 setString 和 setNString 都要求用户在 size 参数里声明表定义中对应列的列宽。
 
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