Adding c3p0 to spring hibernate project - mysql

Question

I had some trouble with connection timeouts. Problem: After mysql timeout hibernate stops working. It seams to work fine, but it does not write further data to database. After searching the logs, I found the hint: last connection 53000 seconds - connection problem. Timeout is mysql-default (28000). So I tried increasing mysql timeout, but won't use in production system.
Searching for a better solution, I found out, that probably c3p0 could solve my problem with a test query.
I am using hibernate with spring. That's were trouble starts. I added c3p0 as DataSource (Bean):
<bean id="dataSource_archiv" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="driverClass" value="${hibernate.connection.driver_class}" />
<property name="jdbcUrl" value="${hibernate.connection.url}" />
<property name="user" value="${hibernate.connection.username}" />
<property name="password" value="${hibernate.connection.password}" />
<property name="minPoolSize" value="${hibernate.connection.minPoolSize}" />
<property name="maxPoolSize" value="${hibernate.connection.maxPoolSize}" />
<property name="maxIdleTime" value="${hibernate.connection.maxIdleTime}" />
<property name="maxStatements" value="${hibernate.connection.maxStmts}" />
<property name="testConnectionOnCheckout" value="${hibernate.connection.testCo}" />
<property name="testConnectionOnCheckin" value="${hibernate.connection.testCo}" />
<property name="preferredTestQuery" value="${hibernate.connection.testSQL}" />
<property name="idleConnectionTestPeriod" value="${hibernate.connection.testPeriod}" />
</bean>
Complete hibernate Config File.
But afterwards, the application cannot be started anymore:
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'appConfig': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field
Complete Stack trace.
So probably I misconfigured something. Where can I start analyzing the problem?
Or is there any other good solution? Like starting a Native SQL from hibernate to keep connection alive? I would prefer the solution with c3p0.
Thanks.