About Tomcat combined with Atomikos to implement JTA

Recently, the project switched the environment and replaced weblogic with tomcat. I recorded the problems encountered in the middle.
Configuring Atomikos to implement JTA under Tomcat
As a classic web server, Tomcat is widely used in development, testing, and production environments. But Tomcat is not a Java EE server after all, so it does not provide support for EJB and JTA. This article describes a method for Tomcat to implement JTA using Atomikos.

 Using JTA in Tomcat, you can deploy Atomikos in Tomcat and use the data source supported by Tomcat; you can also configure it in the project and use Spring to configure the data source, connection pool, transaction manager, etc. The two methods have their own characteristics. This article only introduces the integration of Tomcat and Atomikos. After the integration, Tomcat can provide JTA transaction manager and data source to the outside world.

         Before using Atomikos, we also used JOTM, but under high concurrency conditions, JOTM frequently failed and we had to give up. Through testing, we found that Atomikos had good performance and stability.

         We used the latest version 4.04 of Atomikos. The Jar package can be obtained from the Maven configuration library. The link address is: http://mvnrepository.com/artifact/com.atomikos

If you do not use Hibernate, the required packages include:

atomikos-util.jar,
jta.jar,
transactions.jar,
transactions-api.jar,
transactions-jdbc.jar,
transactions-jta.jar

Integration Package:
atomikos-integration-extension-3.7.2.jar

Remember to put the database driver

Step 1: Copy these jars to the lib directory of tomcat. To integrate Tomcat with Atomikos, you also need an integration package. This integration package contains two classes. You can refer to the implementation yourself or use the official jar package. The latest one is

atomikos-integration-extension-3.7.2.jar

Step 2: Add a listener in tomcat/config/server.xml

<Listener className="com.atomikos.tomcat.AtomikosLifecycleListener" />

Step 3: Add data sources and related transaction managers in tomcat/config/context.xml. The following is a reference example. Modify the parameters as appropriate.

 <Resource name="jdbc/DS_MYSQL"

            auth="Container"

            type="com.atomikos.jdbc.AtomikosDataSourceBean"

            uniqueResourceName="jdbc/DS_MYSQL"

            xaDataSourceClassName="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource"

            xaProperties.databaseName="db_test"

            xaProperties.serverName="localhost"

            xaProperties.port="3306"

            xaProperties.user="root"

            xaProperties.password="root"

            maxPoolSize="200"

            xaProperties.url="jdbc:mysql://localhost:3306/db_test?characterEncoding=UTF8"

            factory="com.atomikos.tomcat.EnhancedTomcatAtomikosBeanFactory" />

  <Resource name="UserTransaction"

            auth="Container"

            type="javax.transaction.UserTransaction" />   

   <Transaction factory="com.atomikos.icatch.jta.UserTransactionFactory" />

Step 4: Add a jta.properties file in the tomcat/lib directory and set the Atomikos transaction-related parameters. Otherwise, the default configuration parameters will be used. Some concurrent transaction numbers (50 by default) and timeouts need to be adjusted. Some parameter configurations in the file are given below. For parameter explanations, please refer to the official documentation: https://www.atomikos.com/Documentation/JtaProperties

Add this line configuration

com.atomikos.icatch.service=com.atomikos.icatch.standalone.UserTransactionServiceFactory

The default values of the parameters in Atomikos are defined in transactions.jar, transactions-default.properties: if you are interested, you can go and see it yourself

After configuring the above four steps, the integration of Tomcat is complete. Spring can be used in the project to associate the data source and transaction manager. The reference configuration is as follows:

<!-- JNDI template configuration information, used to connect to the application server -->

<bean class="org.springframework.jndi.JndiTemplate" id="jndiTemplate" />
<bean class="org.springframework.jndi.JndiObjectFactoryBean" id="dataSource">

    <property name="jndiName">

        <value>java:comp/env/jdbc/DS_MYSQL</value>

    </property>

    <property name="jndiTemplate">

        <ref bean="jndiTemplate"/>

    </property>

</bean>

<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">

    <property name="dataSource">

        <ref bean="dataSource" />

    </property>

</bean>  

<!--User transaction object-->

<bean class="org.springframework.jndi.JndiObjectFactoryBean" id="userTransaction">

    <!--class="org.springframework.transaction.jta.WebLogicJtaTransactionManager">-->

    <property name="jndiName">

        <value>java:comp/UserTransaction</value>

    </property>

    <property name="jndiTemplate">

        <ref bean="jndiTemplate"/>

    </property>

</bean>

<bean id="atomikosTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager"

    init-method="init" destroy-method="close">

    <property name="forceShutdown" value="false" />

</bean>

<!-- Configure annotation-based declarative transaction manager -->

<bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager">

    <property name="userTransaction" ref="userTransaction" />

    <property name="transactionManager" ref="atomikosTransactionManager" />

</bean> 

<tx:annotation-driven transaction-manager="transactionManager" />

The following is the configuration used in my project: It is recommended to configure in conf.xml

The XA data source and JDBC driver used in the Tomcat configuration can use nonXA related settings. Atomikos also supports non-XA connections to increase the running speed. Regarding the nonXa data source, you can refer to the following configuration:
<Resource name="jdbc/DS_MYSQL"

 auth="Container"
    type="com.atomikos.jdbc.nonxa.AtomikosNonXADataSourceBean"

        uniqueResourceName="jdbc/DS_MYSQL"

        driverClassName="com.mysql.jdbc.Driver"

        maxPoolSize="200"

        url="jdbc:mysql://localhost:3306/db_test?characterEncoding=UTF8"

        user="root"

        password="root"

        factory="com.atomikos.tomcat.EnhancedTomcatAtomikosBeanFactory" />

**Pitfall Record**

**Here, because there is a transaction manager TransactionManager, UserTransaction cannot be obtained through this type. After debugging, it is found that this class is not found**

**Change to type="com.atomikos.icatch.jta.userTransactionImp" to successfully obtain UserTransaction,**

 <Resource name="UserTransaction"

            auth="Container"
type="com.atomikos.icatch.jta.userTransactionImp"/>   

   <Transaction factory="com.atomikos.icatch.jta.UserTransactionFactory" />

https://blog.csdn.net/xuyu_yt/article/details/77905553?locationNum=14%20fps=1

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