使用Spring和c3p0和MySQL动态设置连接时区

Question

I want to dynamically set the timezone for a MySQL JDBC connection with c3p0 as connection pool. To set time zone for a given MySQL JDBC connection I know I can use "SET time_zone = '+02:00';", but if I set this on a connection I get from the pool I assume the connection will have this time zone when it is being given back to the pool and given to a new request witch request a connection?!? Have I understood it correct?

If yes, how can I set dynamically in a way that the pooled connection is having its timezone reverted to original one (in my case I use UTC as default on MySQL and in the JCM through TimeZone.setDefault(UTC) during startup of my spring context).

Here is my code snippet from my (Report)Dao

public TrafficDuringDayGroupedByPhoneEvent countAllSummariesForTimeReport(Integer childId, Date start, Date end, MessageType type, TimeZone timezone) {


    Integer[] res = {0, 0, 0, 0};
    Session session = getSession();

    //SET time_zone = '+02:00';
    String sql = "select count(calls.d), d from (SELECT  start_time, \n"
            + "(case when hour(start_time) >= 6 and  hour(start_time) < 9 then 'morning'\n"
            + "when hour(start_time) >= 9 and  hour(start_time) < 15 then 'day'\n"
            + "when hour(start_time) >= 15 and  hour(start_time) < 21 then 'aft'\n"
            + "when hour(start_time) >= 21 and  hour(start_time) <= 24 then 'night'\n"
            + "when hour(start_time) < 6 then 'night' end) as d\n" + "FROM bpr_report_event b inner join ";

    ....
}

My question is similar to the one below, except that I want to set it dynamically per connection, not the same timezone as the guy in the question below does.

Setting connection timezone with Spring and DBCP and MySQL

Answer 1

you can write a c3p0 ConnectionCustomizer which sets the time zone back to UTC onCheckin. See

http://www.mchange.com/projects/c3p0/apidocs/com/mchange/v2/c3p0/ConnectionCustomizer.html

http://www.mchange.com/projects/c3p0/#connection_customizers