Overcome MySQL's connection timeout after 8 hrs idle.

Fixed following exception:

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully
received from the server was 324,520,962 milliseconds ago. The last packet sent successfully to the
server was 324,520,962 milliseconds ago. is longer than the server configured value of
'wait_timeout'. You should consider either expiring and/or testing connection validity before use in
your application, increasing the server configured values for client timeouts, or using the
Connector/J connection property 'autoReconnect=true' to avoid this problem.

@see http://stackoverflow.com/questions/4950396/tomcat-configuration-using-dbcp

Author: php-coder

src/main/java/ru/mystamps/web/config/DataSourceConfig.java

@@ -51,6 +51,8 @@ public DataSource getDataSource() {
 			dataSource.setUrl(env.getRequiredProperty("db.url"));
 			dataSource.setUsername(env.getRequiredProperty("db.username"));
 			dataSource.setPassword(env.getRequiredProperty("db.password"));
+			dataSource.setValidationQuery("SELECT 1");
+			dataSource.setTestOnBorrow(true);
 
 			return dataSource;
 		}