I can use annotation #Transactional at the top of my service PersonServiceBean and config transactionManager like below. After that, my service can execute db operations under transaction control through AOP.
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
.........
</bean>
<tx:annotation-driven transaction-manager="txManager"/>
<bean id="personService" class="cn.itcast.service.impl.PersonServiceBean">
<property name="dataSource" ref="dataSource"/>
</bean>
But i didn't include aspectj.jar into my project. How does it work? I heard spring implements AOP through aspectj.
It doesn't use AspectJ by default, but uses proxies (either JDK interface proxies or CGLIB proxies). So, when you inject a transactional bean into another bean, what you get injected is in fact a proxy to your actual bean instance, which intercepts the method calls and starts/commits/rollbacks transactions.
More in the documentation, of course.
Related
I want to understand how the annotation works. I have this piece of code which I have used in a simple Spring project.
#Resource(name="dataSource")
private DataSource dataSouce;
The dataSource I have defined in an XML config file:
<!-- The Apache DBCP implementation of DataSource -->
<bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource">
<property name="driverClassName" value="org.h2.Driver"/>
<property name="url" value="jdbc:h2:tcp://localhost/~/test"/>
<property name="username" value="sa"/>
<property name="password" value=""/>
</bean>
Other snippet from spring xml config file
<context:annotation-config /> <!-- This enables the annotation's actions, else annotations don't do their work. -->
<context:component-scan base-package="com.example.dao.jdbc.impl"/> <!-- This is for component scan -->
<bean id="jdbcOperImpl" class="com.example.dao.jdbc.impl.JdbcOperImpl"/>
As I understand the Resource annotations comes from javax.annotation.Resource. I looked its source code, and I notices the annotation is defined by JDK SE, and it is just a simple definition of an annotation. How does this do the injection? Does Spring Framework use this annotation and does Injection? How is #Resource annotation and Spring framework related?
Actually Spring supports two types of annotations which are Spring based annotations and Java based annotations. For dependencies you can use #Autowired that completely spring annotations.
#Resource and #Inject are the standard java based annotations. For more clarity see this link http://blogs.sourceallies.com/2011/08/spring-injection-with-resource-and-autowired/
I have a legacy code that use the TransactionManager to obtain access to the transaction to associate synchronization objects to the transaction afterCommit.
When I migrate to Spring 3, the recommended transaction manager to my solution is WebSphereUowTransactionManager, in truth, I feel that it is only a factory to the real Transaction Manager. But this transaction manager always return null in the method getTransactionManager().
I'm using EJB's 2.1 (legacy, remember?) with CMT.
My configuration is Spring 3.1.2.RELEASE, Hibernate 3.6.8.Final, Websphere 6.1.0.43, my beans are:
<bean
id="transactionManager"
class="org.springframework.transaction.jta.WebSphereUowTransactionManager" />
<bean
name="auditContextManager"
class="... my class ...">
<property name="transactionManager">
<bean factory-bean="transactionManager" factory-method="getTransactionManager" />
</property>
</bean>
My hibernate configuration is:
<hibernate-configuration>
<session-factory>
<property name="hibernate.jdbc.fetch_size">200</property>
<property name="hibernate.jdbc.use_get_generated_keys">true</property>
<property name="hibernate.bytecode.use_reflection_optimizer">true</property>
<property name="hibernate.connection.datasource">java:comp/env/jdbc/ORDS</property>
<property name="hibernate.dialect">org.hibernate.dialect.Oracle9iDialect</property>
<property name="hibernate.max_fetch_depth">3</property>
<property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
<property name="hibernate.transaction.factory_class">org.hibernate.transaction.CMTTransactionFactory</property>
<property name="hibernate.transaction.manager_lookup_class">org.hibernate.transaction.WebSphereExtendedJTATransactionLookup</property>
<property name="hibernate.show_sql">false</property>
... too much mappings to show here ...
</session-factory>
</hibernate-configuration>
And my bean auditContextManager has always transactionManager set to null.
It seems to me that WebSphereUowTransactionManager do not expose Transaction Manager intentionally. Is this alright ?
There is any way so I can get the Transaction Manager ? Since WebSphereUowTransactionManager is not really the transaction manager, but only a transaction manager factory.
It is not a factory for the TransactionManager but, as the name suggest, the UOWManager. It uses the Websphere native API for managing transactions (which has broader support for certain things than the plain JTA api).
So there isn't going to be a TransactionManager it will always be null.
Basically if you want the transactionamanager you will have to do a JNDI lookup.
com.ibm.ws.Transaction.TransactionManagerFactory is the factory you should use to get the transaction manager .
I have next applicationContext.xml file on the root of classpath:
<context:annotation-config />
<context:property-placeholder location="classpath:props/datasource.properties" />
<bean id="datasource" class="org.apache.commons.dbcp.BasicDataSource"
p:username="${jdbc.username}"
p:password="${jdbc.password}"
p:url="${jdbc.url}"
p:driverClassName="${jdbc.driverclass}"
p:validationQuery="SELECT sysdate FROM dual" />
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"
p:dataSource-ref="datasource"
p:mapperLocations="classpath:mappers/*-mapper.xml" />
<tx:annotation-driven transaction-manager="txManager" />
<bean id="txManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager"
p:dataSource-ref="datasource" />
<bean id="mappeScannerConfigurere" class="org.mybatis.spring.mapper.MapperScannerConfigurer"
p:sqlSessionFactory-ref="sqlSessionFactory"
p:basePackage="com.mypackage" />
props/datasource.properties also exists on the root of classpath with such content:
jdbc.url=myjdbcurl
jdbc.driverclass=myClass
jdbc.username=myUserName
jdbc.password=myPassword
I have a spring managed test where I declare to use previously mentioned applicationContext.xml via next annotations:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(locations = {"classpath:applicationContext.xml"})
When I invoke test method i get next error from spring:
org.apache.commons.dbcp.SQLNestedException: Cannot load JDBC driver class '${jdbc.driverclass}'
As I understand sping didn't resolve reference to jdbc.driverclass.
What have I done wrong?
PS: I'm using spring 3.2.3.RELEASE
**
EDIT
**
Perhaps the problem may be in MapperScannerConfigurer. It is a BeanDefinitionRegistryPostProcessor and as Javadoc says:
Extension to the standard BeanFactoryPostProcessor SPI,
allowing for the registration of further bean definitions
before regular BeanFactoryPostProcessor detection kicks in
So MapperScannerConfigurer instantiates datasource object via sqlSessionFactory with BeanFacoryPostProcessor(which is responsible for <context:property-placeholder/>) have not been utilized.
So my question transforms to how to reorder BeanFacoryPostProcessor from <context:property-placeholder/> and BeanDefinitionRegistryPostProcessor(MapperScannerConfigurer)?
Resolved
After a couple hours of investigation I found the solution:
As I said earlier MapperScannerConfigurer is a BeanDefinitionRegistryPostProcessor which fires before BeanFactoryPostProcessor which is responsible for <context:property-placeholder/>. So, during the creation of MapperScannerConfigurer references to external properties will not be resolved. In this case we have to defer the creation of datasource to the time after BeanFactoryPostProcessorhave been applied. We can do that in several ways:
remove p:sqlSessionFactory-ref="sqlSessionFactory" from MapperScannerConfigurer. In this case datasource object will not be created before MapperScannerConfigurer, but after BeanFactoryPostProcessor which is responsible for <context:property-placeholder/>. If you have more than one sqlSessionFactory in applicationContext, than can be some troubles
In versions of mybatis-spring module higher than 1.0.2 there is a possibility to set sqlSessionFactoryBeanName instead of sqlSessionFactory. It helps to resolve PropertyPlaceHolder issue with BeanFactoryPostProcessor. It is a recommended way to solve this issue described in mybatis-spring doc
I was having the same issue and came across this post but I was unable to resolve it the same way maks did. What ended up working for me was to set the ignoreUnresolvablePlaceholders property value to true.
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location">
<value>classpath:database.properties</value>
</property>
<property name="ignoreUnresolvablePlaceholders" value="true"/>
</bean>
I am using Spring 3.2.3.RELEASE as well. I realize this post is over 4 months old but I figured someone might find it useful.
Short form: What is the proper way to load an implementation of: BeanDefinitionRegistryPostProcessor?
Expanded form: Is there a way to load BeanDefinitionRegistryPostProcessor before any beans have been created. If you look at the javadoc:
Extension to the standard {#link BeanFactoryPostProcessor} SPI, allowing for
the registration of further bean definitions before regular
BeanFactoryPostProcessor detection kicks in.
So it's meant to be loaded when bean definitions have been created but before any beans have been created. If we just create it as a regular bean in the application xml then it defeats the purpose of having this bean in the first place.
Right now i am using the following bean entry
<bean id="Service" >
<property name="target">
<bean class="someClass" lazy-init="false">
<property name="SessionFactory1"><ref bean="SessionFactory1"/></property>
<property name="SessionFactory2"><ref bean="SessionFactory2"/></property>
<property name="SessionFactory3"><ref bean="SessionFactory3"/></property>
</bean>
</property>
</bean>
Now the requirement is to first check which all session factories have an active datasource and include those only in the above bean definition. So that the application does not break if we try to initialize a session factory with inactive datasource.
sessionfactory initialization will be take care by using seperate config xml for session factories and loading only the ones with active datasources.
Please help on how can this be achieved.
You can use Spring InitializingBean interface, which makes you implement an afterPropertiesSet() method. This method will be executed after Spring instantiates your class, and you could check if your session factories are available or not.
InitializingBean: Interface to be implemented by beans that need to react once all their properties have been set by a BeanFactory: for example, to perform custom initialization, or merely to check that all mandatory properties have been set.
link: Spring InitializingBean
Hello guys I have configured a connection pool and JNDI resource in glassfish 2.1. I can get the Datasource via lookup method in my projects and everything works good. However I decided to try Spring framework and to use my existing connection pool.
In the Spring context file I have the following:
<jee:jndi-lookup id="dataSource" jndi-name="jdbc/name" />
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.simple.SimpleJdbcTemplate">
<constructor-arg ref="dataSource"/>
</bean>
<bean id="dao" class="com.mycompany.mavenproject3.Dao">
<property name="simpleJdbcTemplate" ref="jdbcTemplate"/>
</bean>
When I deploy the project I get:
java.lang.IllegalArgumentException: 'dataSource' or 'jdbcTemplate' is required]
Is there anything else I have to configure in that file or in any other file in order to get the Datasource?
Presumably, com.mycompany.mavenproject3.Dao extends JdbcDaoSupport, but you're setting a property named simpleJdbcTemplate on it, leading me to believe that you've defined your own property to hold the template since that doesn't exist on Spring's implementation. It's therefore complaining at you because you're required to set either the dataSource property or the jdbcTemplate property of the JdbcDaoSupport object before using it, exactly like it's telling you. Change <property name="simpleJdbcTemplate"... to <property name="jdbcTemplate"....
If your DAO doesn't extend JdbcDaoSupport, then find what does and remove it or set its properties appropriately.
You can also call your datasource directly in your dao bean, don't need to do an another bean for jdbcTemplate. So your context file become something like this:
<jee:jndi-lookup id="dataSource" jndi-name="jdbc/name" />
<bean id="dao" class="com.mycompany.mavenproject3.Dao">
<property name="dataSource" ref="dataSource"/>
</bean>
After you just have to extends JdbcDaoSupport spring class (in which contain the getter and setter of datasource) on your Dao class.