top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

How to reset scanner type Scanner ?

0 votes
240 views

I have a file and I am extracting some data from it using key one by one.After a successful match, I want to reset the scanner object to start from the first line of the file again.

posted Aug 23, 2017 by Shivam Kumar Pandey

Looking for an answer?  Promote on:
Facebook Share Button Twitter Share Button LinkedIn Share Button

Similar Questions
+1 vote
What is better to use BufferedReader or Creating scanner object ?

I have a file and using scanner type Scanner to scan each line of this file but I have to create scanner instance for every key value that I want to match with the text of the file.
I want to reset scanner but not able to do so, I searched on the internet and found other way using BufferedReader which will help to get back to the first line of the file.Will it be better to use and is here anyone faced similar issue earlier?

+1 vote
How to update null into a column type Date in MySQL ?

I have a table in Mysql DB like following

mysql> describe APPTBL;
+-------------+-------------+------+-----+---------+----------------+
| Field       | Type        | Null | Key | Default | Extra          |
+-------------+-------------+------+-----+---------+----------------+
| APP_ID      | int(11)     | NO   | PRI | NULL    | auto_increment |
| CREATE_DATE | date        | YES  |     | NULL    |                |
| CLOSE_DATE  | date        | YES  |     | NULL    |                |
| ACTION      | text        | YES  |     | NULL    |                |
+-------------+-------------+------+-----+---------+----------------+

While Starting of App, i am inserting the app details with CREATE_DATE and when it is closing, i am updating its CLOSE_DATE. But in case if user is restarting the app, i want to update NULL in place of CLOSE_DATE column. Here is my query,

mysql> update APPTBL set CLOSE_DATE = NULL where APP_ID = 1;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0
mysql> select * from APPTBL ;
+-----------+-------------+------------+------------+
|   APP_ID  | CREATE_DATE | CLOSE_DATE |   ACTION   |
+-----------+-------------+------------+------------+
|    1      |  2013-10-08 | NULL       | XXXXXYYYYY |
+-----------+-------------+------------+------------+
1 row in set (0.00 sec)

But why i am not getting any result in this??

mysql> select * from APPTBL where CLOSE_DATE = NULL;
Empty set (0.00 sec)

Also, as i am writhing a java program using this where 

rs = st.executeQuery("update APPTBL set CLOSE_DATE = NULL where APP_ID = 1");
if(!rs.wasNull()){
   // Why it is coming here??
}
...