I've been doing a research on connection pool with JDBC api and classes. But still I don't know how to configure a Connection Pool class for a java web project. As you may know, the Connection Pool is a Singleton Class that encapsulates the JDBC apis. But the Connection Class is started once when the web project is deployed on Tomcat Server, I wonder if there's something needed to be done with Web.xml configuration file, to let Tomcat Server load the Connection Pool Class.
Thank you very much for your time!
There a many ways of doing this. JNDI is one way - but it is not so "user friendly" in tomcat. The datasource also can be configured in Spring. For e.g.:
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${jdbc.driverClassName}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</bean>
The most simplest way of doing this is to create a ServletContextListener class, create your datasource and put it into ServletContext so that the same instance could be retrieved from ServletContext in your project.
See my answer here how to create ServletContextListener.
See also:
How to use JNDI DataSource provided by Tomcat in Spring?
Related
When I debug my Mule application i have error:
org.springframework.dao.DataAccessResourceFailureException: Error retrieving database metadata; nested exception is org.springframework.jdbc.support.MetaDataAccessException: Could not get Connection for extracting meta data; nested exception is org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: No suitable driver found for jdbc:h2:~/test
my java code:
SimpleJdbcCall call = new SimpleJdbcCall(jdbcTemplate.getDataSource()).withProcedureName("my_procedure_name").withSchemaName("my_schema");
...
call.execute(in)
my aaplicationContext:
<bean id="dataSource2"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${db2.driver}" />
<property name="url" value="${db2.url}" />
<property name="username" value="${db2.user}" />
<property name="password" value="${db2.password}" />
</bean>
my app_name.properties:
db2.url=jdbc:h2:~/test
db2.driver=org.h2.Driver
db2.user=sa
db2.password=
my pom:
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>1.4.200</version>
</dependency>
my classpath:
<classpathentry kind="var" path="M2_REPO/com/h2database/h2/1.4.200/h2-1.4.200.jar"/>
log info after run application:
INFO org.springframework.jdbc.datasource.DriverManagerDataSource - Loaded JDBC driver: org.h2.Driver
Also i put h2-1.4.200.jar (when I starting my application from AnypointStudio) to:
c:\...\plugins\org.mule.tooling.server.3.9.0_6.4.0.201908221250\mule\lib\user\
and:
c:\...\plugins\org.mule.tooling.server.3.9.0_6.4.0.201908221250\mule\lib\boot\
and:
c:\...\plugins\org.mule.tooling.server.3.9.0_6.4.0.201908221250\mule\lib\mule\
and when I run application from mule server h2-1.4.200.jar, I put here:
..\mule-standalone-3.9.0\lib\boot
and
..\mule-standalone-3.9.0\lib\user
and:
..\mule-standalone-3.9.0\lib\mule
why application driver h2 not found ? what's the problem ?
Thanks.
You are mixing 3 different ways of managing the JDBC driver dependency, and also duplicating the library in the runtimes. That also makes it more difficult to understand the problem, and to deploy an application.
Let's start with Maven. It looks like you are using the right dependency in the pom, as long as it is in the section.
If the project is using Maven, there should not be any need to look into , unless it is out of sync with Maven. You should not change the class path manually, or edit the build path in Anypoint Studio. These are part of Studio/Eclipse .classpath files and should be left alone. Be sure to update the project so Studio regenerates the classpath.
About MULE_HOME\lib\boot, MULE_HOME\lib\user, MULE_HOME\lib\mule (either in Studio or standalone), you should not put the library in there. The Maven dependency is enough and you are duplicating the versions. Even if you can share a library in lib\user, it is not recommended. It makes more difficult to replicate sanely a deployment and again, there is no need for the JDBC driver. You should not put anything at all in lib\boot nor lib\mule nor the other subdirectories of lib. These are reserved for the runtime.
Try removing all those extras first and see what happens with a clean deployment.
Update:
Once the libraries are cleaned up, take into account that the Spring class may have some classloading issues itself. It is almost always better to use a datasource pool implementation. There are several to choose, like c3p0, dbcp, and others.
One example with c3p0:
<spring:bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<spring:property name="driverClass" value="${JDBC.driver}"/>
<spring:property name="jdbcUrl" value="${JDBC.URL}"/>
<spring:property name="user" value="${JDBC.user}"/>
<spring:property name="password" value="${JDBC.password}"/>
<spring:property name="minPoolSize" value="5"/>
<spring:property name="maxPoolSize" value="20"/>
</spring:bean>
See https://help.mulesoft.com/s/article/Spring-based-datasources for more examples.
How does spring know which connection pool to use?
As is known ,you tell the spring framework a persistence-unit name,and annotate the entity manager with #PersistenceContext,and with Persistence.xml configured.Spring does every thing for you.
I am very confused about the spring annotation "#PersitenceContext" above the entityManager field.
My persistence.xml is as below :
<persistence-unit name="hibernate.recommendation_report.jpa">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<properties>
<property name="javax.persistence.jdbc.driver" value="oracle.jdbc.OracleDriver" />
<property name="javax.persistence.jdbc.url" value="jdbc:oracle:thin:#192.168.113.226:11521:BOSS" />
<property name="javax.persistence.jdbc.user" value="xxxx" />
<property name="javax.persistence.jdbc.password" value="xxxx" />
</properties>
</persistence-unit>
My tomcat server and my webapp work well when and after for a short peoriod of time after the starting up of tomcat server.But hours later,the server reports a sqlexception "Connection already closed".
Is this the problem of misusing db connection pool? How do the spring framework choose a c3p0 or DBCP ? How would I specify the connection pool? Or is the tomcat uses the default DBCP as the connection pool?
U can make your tomcat server or other app server provide the JNDI datasource. So that, the your server container's self-contained connection pool can take good care of your the database connection/session.
Tomcat in your case, you specify the JNDI datasource in the $TOMCAT_HOME/conf/context.xml or server.xml:
<Resource name="jdbc/sample" auth="Container"
type="com.mchange.v2.c3p0.ComboPooledDataSource"
username=...
password=...
url=...
driverClassName=...
/>
the type attribute tells the tomcat which connection pool to use.
By default tomcat6 uses DBCP with type of "java.sql.DataSource".
Make sure to use the JNDI reference in your persistence.xml:
<persistence version="2.1" ....>
<persistence-unit name="hibernate.recommendation_report.jpa">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<non-jta-data-source>java:comp/env/jdbc/sample</non-jta-data-source>
</persistence-unit>
</persistence>
Or use spring xml to config the datasource bean to inject into the your entityManagerFactory.Please refer to here.
<jee:jndi-lookup id="dataSource" jndi-name="java:sample"/>
See other JNDI resource attributes available for DBCP.
Note: the "java:comp/env/" prefix in persistence.xml data-source is very import.Without it, Spring will not look for the pool provided by your application server to fetch datasource but just use the attribute to construct a simple datasource.
Note: tomcat8 itself provides a even better pool.If you upgrade to tomcat8.
I was wondering if anyone has any code examples for setting up a connection pool in Tomcat (7 or later) using MyBatis as the ORM.
I presume I need to add a resource to my context.xml file in my Tomcat conf folder and then link that to MyBatis. I've had a look and any tutorials I have found seem to be Spring specific. Does anyone have a simple tutorial or can they outline the steps required to get this up and running?
There is this old entry in the iBatis FAQ that should still be applicable to myBatis: How do I use a JNDI DataSource with iBATIS in Tomcat?.
You can google for the details to configure a datasource in your Tomcat version, then configure MyBatis as well (it's different than the iBatis configuration):
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="JNDI">
<property name="data_source" value="java:comp/env/jdbc/yourDatasourceName"/>
</dataSource>
</environment>
There are a number of ways you can do this. I am assuming that you mean to implement Tomcat (as opposed to Spring) managed connection pooling. I have tested on MySQl/Spring 4/Mybatis-spring 1.1 stack.
Figure out the connection pooling mechanism you want to implement (C3P0/DBCP etc).
If you want to use your database as a JNDI data source, then you have to declare it as a resource in Tomcat settings. There are a number of ways to do this. You can follow this well written guide Tomcat JNDI connection pooling. I generally add the following entry in context.xml located in the META-INF directory of my app:
<Context>
<Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource" maxTotal="100" maxIdle="30" maxWaitMillis="10000" username="javauser" password="javadude" driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost:3306/javatest"/>
</Context>
This file is used by Tomcat to invoke its own default connection pool, which in this case would be DBCP 2. You can tweak its settings by adding more parameters (like removeAbandonedOnBorrow=true) in the Resource element above. You should put the driver jar (eg MySQL Connector Jar) of your database in Tomcat's lib folder.
After this, depending on your Mybatis implementation (XML or bean based), you can inject this data source into Mybatis. If you are doing it the bean way, you can do it like this:
<bean id="dbDataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName" value="java:comp/env/jdbc/TestDB"/>
</bean>
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dbDataSource" />
</bean>
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dbDataSource" />
<property name="typeAliasesPackage" value="com.example.model"/>
<property name="mapperLocations" value="classpath*:*.xml" />
</bean>
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.example.dao" />
</bean>
MapperScannerConfigurer is necessary because it searches the directories given to it to find mapper xml files. You can also use the old way of defining a mybatis-config.xml file by injecting the file's location in the sqlSessionFactory bean in its configLocation property.
I have a Java EE application which uses Hibernate 4.2.7 as persistence provider executing Junit tests in an embeddable Websphere 8.0.0 container. Database access works fine in a real (i.e. non-embedded) Websphere 8.0.0 instance. The unit tests do work when run with OpenJPA instead of Hibernate. However, running the Junit tests with Hibernate, I get the following exception:
CNTR0020E: EJB threw an unexpected (non-declared) exception during invocation of method "getEntity" on bean "BeanId(embeddable#classes#SomeBean, null)". Exception data: org.hibernate.service.jndi.JndiException: Unable to lookup JNDI name [java:comp/websphere/ExtendedJTATransaction]
at org.hibernate.service.jndi.internal.JndiServiceImpl.locate(JndiServiceImpl.java:68)
at org.hibernate.service.jta.platform.internal.WebSphereExtendedJtaPlatform$TransactionManagerAdapter$TransactionAdapter.(WebSphereExtendedJtaPlatform.java:156)
at org.hibernate.service.jta.platform.internal.WebSphereExtendedJtaPlatform$TransactionManagerAdapter$TransactionAdapter.(WebSphereExtendedJtaPlatform.java:152)
at org.hibernate.service.jta.platform.internal.WebSphereExtendedJtaPlatform$TransactionManagerAdapter.getTransaction(WebSphereExtendedJtaPlatform.java:124)
at org.hibernate.service.jta.platform.internal.WebSphereExtendedJtaPlatform$TransactionManagerAdapter.getStatus(WebSphereExtendedJtaPlatform.java:119)
at org.hibernate.engine.transaction.internal.jta.JtaStatusHelper.getStatus(JtaStatusHelper.java:73)
at org.hibernate.engine.transaction.internal.jta.JtaStatusHelper.isActive(JtaStatusHelper.java:115)
at org.hibernate.service.jta.platform.internal.TransactionManagerBasedSynchronizationStrategy.canRegisterSynchronization(TransactionManagerBasedSynchronizationStrategy.java:56)
... stripped ...
It seems the implementation of WebsphereExtendedJtaPlatform is trying to get the current transaction via a JNDI lookup but fails because that JNDI name does not exist in the embedded container. Here's a snipped from org.hibernate.service.jta.platform.internal.WebsphereExtendedJtaPlatform:
public class TransactionAdapter implements Transaction {
private TransactionAdapter() {
if ( extendedJTATransaction == null ) {
extendedJTATransaction = jndiService().locate( "java:comp/websphere/ExtendedJTATransaction" );
}
}
... stripped ...
The class ExtendedJtaTransaction itself does exist on the class path inside com.ibm.ws.runtime.jar.
The settings in our persistence.xml look like this:
<persistence-unit name="BLA" transaction-type="JTA">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<jta-data-source>jdbc/BLA</jta-data-source>
<class>com.some.Entity</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect" />
<property name="hibernate.archive.autodetection" value="class" />
<property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.WebSphereExtendedJTATransactionLookup" />
<property name="jta.UserTransaction" value="java:comp/UserTransaction" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.format_sql" value="true" />
<property name="hibernate.jdbc.fetch_size" value="100" />
<property name="hibernate.temp.use_jdbc_metadata_defaults" value="false" />
</properties>
Does anyone have a solution for this?
Thanks!
Transaction strategy configuration
Hibernate requires the configuration of two essential pieces in order to properly run with transactions. The first, hibernate.transaction.factory_class, defines transactional control and the second, hibernate.transaction.manager_lookup_class, defines the mechanism for registration of transaction synchronization so the persistence manager is notified at transaction end when it needs to synchronize changes with the database. For transactional control, both container-managed and bean-managed configurations are supported. The following properties must be set in Hibernate.cfg.xml when using Hibernate with WebSphere Application Server:
for container-managed transactions:
<property name="hibernate.transaction.factory_class">
org.hibernate.transaction.CMTTransactionFactory
</property>
<property name="hibernate.transaction.manager_lookup_class">
org.hibernate.transaction.WebSphereExtendedJTATransactionLookup
</property>
for bean-managed transactions:
<property name="hibernate.transaction.factory_class">
org.hibernate.transaction.JTATransactionFactory
</property>
<property name="hibernate.transaction.manager_lookup_class">
org.hibernate.transaction.WebSphereExtendedJTATransactionLookup
</property>
<property name="jta.UserTransaction">
java:comp/UserTransaction
</property >
The jta.UserTransaction property configures the factory class to obtain an instance of a UserTransaction object instance from the WebSphere container.
The hibernate.transaction.manager_lookup_class property is supported on the WebSphere platform by WebSphere Application Server V6.x and later, and on WebSphere Business Integration Server Foundation V5.1 and later. This property configures Hibernate to use the ExtendedJTATransaction interface, which was introduced in WebSphere Business Integration Server Foundation V5.1 and WebSphere Application Server V6.0. The WebSphere ExtendedJTATransaction interface establishes a pattern that is formalized in Java EE 5 via the JTA 1.1 specification.
I have a Spring webapp running in Tomcat.
This app also needs to expose a service for remote access via RMI. I am using Spring's RmiServiceExporter to do this :
<bean class="org.springframework.remoting.rmi.RmiServiceExporter">
<property name="serviceName" value="${server.rmi.remoteServiceName}"/>
<property name="service" ref="remoteFacade"/>
<property name="serviceInterface" value="my.ServiceInterface"/>
<!-- defaults to 1099 -->
<property name="registryPort" value="${server.rmi.registryPort}"/>
</bean>
It works well, but when I shutdown Tomcat, it hangs and I have to kill it and then manually kill the Java process it has created for the RMI registry. It seems to be because I should explicitely close (i.e. call the close() method) on the context that created the RmiServiceExporter, in this case my application context (not the web context). (source : https://issues.springsource.org/browse/SPR-5601)
How to achieve this (call the close() method on the context when the application is being stopped) in a webapp, where the context is created by a ServletContextListener (org.springframework.web.context.ContextLoaderListener) ?
EDIT: My question was actually misleaded. The context is actually already being closed, and the RmiServiceExporter's destroy() method as well. The problem (tomcat unable to shutdown properly) seems to come from something else. May the users who spent time asnwering this question pardon my haste in posting it.
1)Add destroy method to your bean definition:
<bean class="org.springframework.remoting.rmi.RmiServiceExporter" destroy-method="destroy">
<property name="serviceName" value="${server.rmi.remoteServiceName}"/>
<property name="service" ref="remoteFacade"/>
<property name="serviceInterface" value="my.ServiceInterface"/>
<!-- defaults to 1099 -->
<property name="registryPort" value="${server.rmi.registryPort}"/>
</bean>
2)if you have link to context instance add shutdown hook
context.registerShutdownHook();
Try to start your application context by using ContextLoaderListener as described here. It should close the context automatically for you.