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DataSource in an OSGI container

I have a simple Spring App that connects to a DB via an EntityManager
So I have to following configuration:
<bean id="domainEntityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitName" value="TheManager" />
<property name="dataSource" ref="domainDataSource" />
<property name="packagesToScan" value="com.conztanz.persistence.stock.model" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
</property>
<property name="jpaProperties">
<props>
<prop key="hibernate.hbm2ddl.auto">create-drop</prop>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
</props>
</property>
</bean>
<bean id="domainDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.postgresql.Driver" />
<property name="url" value="jdbc:postgresql://localhost:5433/dbName" />
<property name="username" value="xxxx" />
<property name="password" value="xxxx" />
</bean>
This works fine when lunched via a main class (loading the AppContext manually)
But, once deployed into ServiceMix I get the following error :
Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [org.postgresql.Driver]
I've read somewhere that OSGI and DriverManager don't mix well but I fail to understand why.
The solution that seems to be a good practice is to expose the dataSource as an OSGI bundle, do you agree ? and in that case how would you have access to it from a spring context to be able to have an EntityManager for example ?

DriverManager does not work well in OSGi. The easiest way is to use a DataSource directly. Most DB drivers have such a class. If you instantiate it in your app context then it will work. The downside is though that it binds your application to the DB driver as it then will import the packages for the DataSource impl.
A more loosely coupled way is to use ops4j pax jdbc. It allows to create a DataSource as an OSGi service from a config in config admin. So in your app context you just have to add a dependency to a DataSource service. So your application is not bound to the specific DB driver. One typical use case is to use H2 in tests and oracle in production.

How jdbc connectvity should work in Spring MVC

Below is the way, i am using jdbc connectivity for my spring mvc.
I have some technical doubts, which follows-
1.
As i have invoked datasource object in every bean that requires db connectivity. Is it the right way of doing it?
What if i don't want a particular repository object to be instantiated when the application starts up
(because I'm not sure when user will invoke the object, so why instantiate it at the very beginning)?
<bean
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location">
<value>classpath:jdbc.properties</value>
</property>
</bean>
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
destroy-method="close">
<property name="driverClass" value="${jdbc.driverClassName}" />
<property name="jdbcUrl" value="${jdbc.url}" />
<property name="user" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
<property name="maxPoolSize" value="${jdbc.maxPoolSize}" />
<property name="minPoolSize" value="${jdbc.minPoolSize}" />
<property name="maxStatements" value="${jdbc.maxStatements}" />
<property name="testConnectionOnCheckout" value="${jdbc.testConnection}" />
</bean>
<bean id="ustestuthenticationRepository"
class="com.test.repository.impl.UstestuthenticationRepositoryImpl">
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="someclass"
class="com.test.repository.impl.someclass">
<property name="dataSource" ref="dataSource" />
</bean>
2.
#Qualifier("dbDataSource")
private static DataSource dataSource;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
and then creating
JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
I'm not sure if this is the right way of invoking datasource.If each and every Repository object creates separate jdbctemplate, is it something appropriate?
In every repository class, i am invoking datasource in the folowing way-
Modified Code
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<constructor-arg ref="dataSource" />
</bean>
<bean id="someclass" class="com.era.repository.impl.someclass">
<property name="jdbcTemplate" ref="jdbcTemplate" />
</bean>
and implementation in someclass is -
private JdbcTemplate jdbcTemplate;
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
then only accessing jdbcTemplate variable wherever is required.
Am i doing it correctly now? Please advise.

What you done is not an error. It is possible to work that way.
However.
It means you will simply work with JDBC directly.
It means, you need handle transactions "manually".
It is hard and a lot of code.
You better use spring data and hibernate.
Or spring data and JPA.
Anyway, spring data will help you to manage all resources and will simplify data access for you.
If you already on spring MVC, take also spring data. Why bother?
Official spring data example:
https://spring.io/guides/gs/accessing-data-jpa/

Usage of P6Spy with datasource in Spring applicationContext.xml

I am using Hibernate 4, Spring 3, JSF 2.0 and Weblogic 10.3.6 as server.
I have created datasource on Weblogic server and in applicationContext.xml I have defined datasource as
<!-- Data Source Declaration -->
<bean id="DataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName" value="jdbc/​myDS"/>
</bean>
If I would want to use the P6Spy for logging SQL parameters, how can and where I should add the following in applicationcontext.xml?
<property name="hibernate.connection.driver_class">com.p6spy.engine.spy.
P6SpyDriver</property>
Any help is highly appreciable.
Thanks

The easiest way to integrate p6spy using spring is to use the P6DataSource class. The P6DataSource class is just a proxy for the real data source. This lets you obtain the real data source using any of the spring data source factory implementations.
<bean id="dataSource" class="com.p6spy.engine.spy.P6DataSource">
<constructor-arg>
<bean id="DataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName" value="jdbc/​myDS"/>
</bean>
</constructor-arg>
</bean>
If you are using an XADatasource, just change the classname to P6ConnectionPoolDataSource as shown below. Note: P6ConnectionPoolDataSource implements the ConnectionPoolDataSource and XADataSource interfaces.
<bean id="dataSource" class="com.p6spy.engine.spy.P6ConnectionPoolDataSource">
<constructor-arg>
<bean id="DataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName" value="jdbc/​myDS"/>
</bean>
</constructor-arg>
</bean>

You need to create bean of session factory in applicationContext.xml file as follows:
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource">
<ref bean="dataSource" />
</property>
</bean>
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.p6spy.engine.spy.
P6SpyDriver" />
<property name="url" value="jdbc\:mysql\://localhost\:3306/testdb" />
<property name="username" value="my_username" />
<property name="password" value="my_password" />
</bean>
Please refer to: http://www.mkyong.com/hibernate/how-to-display-hibernate-sql-parameter-values-solution/ for more about P6Spy library.
We can omit "dataSource" bean and directly write properties. Ref: how to configure hibernate config file for sql server

Inject entity manager from XML in Spring

I need to do very similar thing to what is described in Injecting Entitymanager via XML and not annnotations, but I need to inject from XML the real, container-created, entity manager, so that it behaves exactly as if there is a real #PersistenceContext annotation. I've found a LocalEntityManagerFactoryBean (notice missing "Container" word), but I'm affraid that it creates a new entity manager factory and therefore entity manager won't be compatible with that injected via real #PersistenceContext annotation.
I will describe the reason, because it is weird and maybe the solution to my problem is to choose completely different approach. I'm using PropertyPlaceholderConfigurer in my spring configuration and in this configurer I'm referencing other beans. I'm experiencing a bug that autowiring doesn't work in those referenced beans. I don't know why and how PropertyPlaceholderConfigurer turns off autowiring in those referenced beans but the fact is, that if I replace autowiring by xml configuration for those beans, everything works. But I'm unable to replace autowiring of EntityManager, since it's not standard spring bean, but jndi-loaded something I don't fully understand.
One way or the other, is there some solution?

in spring-bean.xml ,
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitName" value="USER_TEST"/>
<property name="jpaVendorAdapter" ref="jpaVendorAdapter"/>
<property name="jpaDialect">
<bean class="org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect"/>
</property>
<property name="jpaPropertyMap">
<props>
<prop key="eclipselink.weaving">false</prop>
</props>
</property>
<bean id="PersonDao" class="com.xxx.java.person.persistence.PersonDAO">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>

<bean id="earlyInitializedApplicationSettingsService" class="...services.impl.ApplicationSettingsServiceImpl" autowire-candidate="false">
<property name="applicationSettingsDao">
<bean class="....impl.ApplicationSettingsDaoImpl">
<property name="entityManager">
<bean class="org.springframework.orm.jpa.support.SharedEntityManagerBean">
<property name="entityManagerFactory">
<bean class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName" value="java:comp/env/persistence/somePersistenceUnit"/>
</bean>
</property>
</bean>
</property>
</bean>
</property>
</bean>
Notice mainly the fact, that I'm not using standard jee:jndi-lookup, because it didn't work (in the conditions created by PropertyPlaceholderConfigurer) and that was the source of my confusion. When I used direct JndiObjectFactoryBean, it worked.

Single database connection with HibernateTemplate and SessionFactory

on the java side, everything works fine but when I look to the V$SESSION special oracle table , and in my log table that records any login or logoff operations, that's a disaster... every single query does a login/logoff operation. So here's my question : Is there any way to configure Spring to have a unique connection to the database or is there something wrong in the way I do the connection ?
Here, my datasource bean configuration :
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName">
<value>oracle.jdbc.OracleDriver</value>
</property>
<property name="url">
<value>jdbc:oracle:thin:#nanssunorad:1523:nanorad3</value>
</property>
<property name="username">
<value>foo</value>
</property>
<property name="password">
<value>bar</value>
</property>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="configLocation">
<value>hibernateESign.cfg.xml</value>
</property>
<property name="dataSource">
<ref bean="dataSource" />
</property>
<property name="configurationClass">
<value>org.hibernate.cfg.AnnotationConfiguration</value>
</property>
</bean>
<bean id="transactionManager"
class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory">
<ref local="sessionFactory" />
</property>
</bean>
<bean id="IXalVaParametresDAO" class="fr.asterion.archivage.hibernate.XalVaParametresDAO">
<property name="sessionFactory">
<ref local="sessionFactory" />
</property>
</bean>
In my app, to get the DAO for the database parameters, I do a
IXalVaParametresDAO parametreDAO = (IXalVaParametresDAO) ConfigApplication
.getApplicationContext(this.log).getBean("IXalVaParametresDAO");
And at last, in my DAO class, I do someting like this :
public class XalVaParametresDAO implements IXalVaParametresDAO
{
private HibernateTemplate hibernateTemplate;
public void setSessionFactory(SessionFactory sessionFactory)
{
this.hibernateTemplate = new HibernateTemplate(sessionFactory);
}
public List<XalVaParametres> findAll()
{
log.debug("finding all XalVaParametres instances");
try
{
String queryString = "from XalVaParametres";
List lst = this.hibernateTemplate.find(queryString);
In my app, each time I call the "find" method, it does a DB login/logoff. I guess the problem is the same on another DB. Am I doing the things right ? I guess not. I wish the HibernateTemplate would create and keep the session open once and for all. Is that possible ?
Thanks for your ideas
Manux

Use a pooling DataSource, e.g. Apache Commons / DBCP's BasicDataSource
Reference:
Spring JDBC > Controlling Database Connections
Spring ORM > Hibernate > SessionFactory setup in a Spring
container

It's not recommended to use DriverManagerDataSource in production, since it doesn't perform connection pooling.
You need to use connection pool instead, such as c3p0 or Apache DBCP.

Its better to use the connection pooling of the application server and specify the jndi in spring xml file :
<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName" value="jdbc/DSTest"/>
</bean>

You can use the native oracle datasource with connection caching like:
<bean id="myDataSource" class="oracle.jdbc.pool.OracleDataSource" destroy-method="close">
<property name="connectionCachingEnabled" value="true"/>
<property name="URL">
<value>${jdbc.url}</value>
</property>
<property name="user">
<value>${jdbc.username}</value>
</property>
<property name="password">
<value>${jdbc.password}</value>
</property>
<property name="connectionCacheProperties">
<value>
MinLimit:1
MaxLimit:1
InitialLimit:1
ConnectionWaitTimeout:120
InactivityTimeout:180
ValidateConnection:true
MaxStatementsLimit:0
</value>
</property>
</bean>