Archive for the ‘JDBC’ Category
JDBC and MySQL: Getting rid of the dreaded message – WARN: Establishing SSL connection without server’s identity verification is not recommended
Written by Chad Darby Friday, 20 May 2016
When connecting to a MySQL database, you may encounter this scary warning message.
Thu Feb 04 14:49:25 IST 2016 WARN: Establishing SSL connection without server’s identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn’t set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to ‘false’. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
Your app will continue to work fine … it is just the MySQL database yelling at you.
To get rid of the warning message. Append ?useSSL=false to the end of your database connection string.
For example,
Replace – jdbc:mysql://localhost:3306/demo
With – jdbc:mysql://localhost:3306/demo?useSSL=false
Note that I appended ?useSSL=false to the end.
That will get rid of the pesky message … whew!
Posted under How-To, Java, JDBC, MySQL | No Comments
JDBC BLOB: Handling large file sizes
Written by Chad Darby Tuesday, 27 October 2015
JDBC has support for storing binary files in the database using the BLOB datatype. I covered this in a previous blog post: Reading and Writing BLOBs with MySQL.
However, you may run into errors if you need to store large files. In particular, you may encounter the following error messages:
Packets larger than max_allowed_packet are not allowed.
Data too long for column 'xxx' at row 1.
By default, the BLOB datatype can only handle files up to 64KB.
MySQL has multiple datatypes for handling binary data:
TINYBLOB : maximum length of 255 bytes
BLOB : maximum length of 65,535 bytes
MEDIUMBLOB : maximum length of 16,777,215 bytes
LONGBLOB : maximum length of 4,294,967,295 bytes
Storing Larger Files
If you need to store larger files, then follow these steps:
1. Change the databtype of your BLOB column to LONGBLOB
ALTER TABLE `demo`.`employees` CHANGE COLUMN `resume` `resume` LONGBLOB NULL DEFAULT NULL ;
2. Edit the MySQL configuration file
On MS Windows: C:\Program Files\MySQL\MySQL Server x.x\my.ini
On Mac: /usr/local/mysql/my.cnf
In this file, add the line:
max_allowed_packet=256M
See the image below
3. Save the file and restart your MySQL server
4. Test your application again. You will now be able to store large files.
Enjoy 🙂
Posted under How-To, Java, JDBC, MySQL | No Comments
Smiley Face
Written by Chad Darby Monday, 13 April 2015
Tweets like this bring a smile to my face. ’nuff said 🙂
Posted under Java, JDBC, Passion | No Comments