java - Apache dbutils Java 无法获取字符串值

Question

QueryRunner qr = new QueryRunner(C3P0Util.getDataSource());
        qr.update("DELETE FROM course_access " +
                "WHERE user_id = ? " +
                "AND course_id NOT IN (?)", user_id, courseIdList);

String user_id = "2"
String courseIdList = "101,102,104,105,106,108,109"
但结果不正确
只有结果相同

DELETE FROM course_access WHERE user_id=2 AND course_id NOT IN (101)

表结构如下所示

id  course_id  user_id
1    101          1
2    102          1
3    105          1
4    104          1
5    106          1
6    108          1
11   110          1
12   101          2
26   101          8
27   102          8
28   105          8
29   104          8
30   106          8
31   108          8
32   110          8
33   113          8
34   115          1
35   107          1
36   115          8
37   109          8
38   109          1
39   107          8
40   116          8
41   116          1
98   102          2
99   103          2
100  104          2
101  105          2
102  106          2
103  107          2
104  108          2
105  109          2