问题
With this configuration (MainConfig.java):
import javax.transaction.TransactionManager;
import javax.transaction.UserTransaction;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.vendor.Database;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.jta.JtaTransactionManager;
import com.atomikos.icatch.jta.UserTransactionImp;
import com.atomikos.icatch.jta.UserTransactionManager;
@Configuration
@ComponentScan
public class MainConfig {
@Bean
public JpaVendorAdapter jpaVendorAdapter() {
HibernateJpaVendorAdapter hibernateJpaVendorAdapter = new HibernateJpaVendorAdapter();
hibernateJpaVendorAdapter.setShowSql(true);
hibernateJpaVendorAdapter.setGenerateDdl(true);
hibernateJpaVendorAdapter.setDatabase(Database.MYSQL);
return hibernateJpaVendorAdapter;
}
@Bean(name = "userTransaction")
public UserTransaction userTransaction() throws Throwable {
UserTransactionImp userTransactionImp = new UserTransactionImp();
userTransactionImp.setTransactionTimeout(10000);
return userTransactionImp;
}
@Bean(name = "atomikosTransactionManager", initMethod = "init", destroyMethod = "close")
public TransactionManager atomikosTransactionManager() throws Throwable {
UserTransactionManager userTransactionManager = new UserTransactionManager();
userTransactionManager.setForceShutdown(false);
return userTransactionManager;
}
@Bean(name = "transactionManager")
@DependsOn({ "userTransaction", "atomikosTransactionManager" })
public PlatformTransactionManager transactionManager() throws Throwable {
UserTransaction userTransaction = userTransaction();
TransactionManager atomikosTransactionManager = atomikosTransactionManager();
return new JtaTransactionManager(userTransaction, atomikosTransactionManager);
}
}
(CustomerConfig.java)
import java.util.Properties;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import com.atomikos.jdbc.AtomikosDataSourceBean;
import com.mysql.jdbc.jdbc2.optional.MysqlXADataSource;
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = "com.at.mul.repository.customer", entityManagerFactoryRef = "customerEntityManager", transactionManagerRef = "transactionManager")
public class CustomerConfig {
@Autowired
private JpaVendorAdapter jpaVendorAdapter;
@Bean(name = "customerDataSource", initMethod = "init", destroyMethod = "close")
public DataSource customerDataSource() {
MysqlXADataSource mysqlXaDataSource = new MysqlXADataSource();
mysqlXaDataSource.setUrl("jdbc:mysql://localhost:3306/atomikos_1");
mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
mysqlXaDataSource.setPassword("password");
mysqlXaDataSource.setUser("root");
mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
AtomikosDataSourceBean xaDataSource = new AtomikosDataSourceBean();
xaDataSource.setXaDataSource(mysqlXaDataSource);
xaDataSource.setUniqueResourceName("xads1");
return xaDataSource;
}
@Bean(name = "customerEntityManager")
public LocalContainerEntityManagerFactoryBean customerEntityManager() throws Throwable {
LocalContainerEntityManagerFactoryBean entityManager = new LocalContainerEntityManagerFactoryBean();
entityManager.setDataSource(customerDataSource());
entityManager.setJpaVendorAdapter(jpaVendorAdapter);
entityManager.setPackagesToScan("com.at.mul.domain.customer");
entityManager.setPersistenceUnitName("customerPersistenceUnit");
Properties properties = new Properties();
properties.put("javax.persistence.transactionType", "JTA");
entityManager.setJpaProperties(properties);
return entityManager;
}
}
(OrderConfig.java)
import java.util.Properties;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import com.atomikos.jdbc.AtomikosDataSourceBean;
import com.mysql.jdbc.jdbc2.optional.MysqlXADataSource;
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = "com.at.mul.repository.order", entityManagerFactoryRef = "orderEntityManager", transactionManagerRef = "transactionManager")
public class OrderConfig {
@Autowired
private JpaVendorAdapter jpaVendorAdapter;
@Bean(name = "orderDataSource", initMethod = "init", destroyMethod = "close")
public DataSource orderDataSource() {
MysqlXADataSource mysqlXaDataSource = new MysqlXADataSource();
mysqlXaDataSource.setUrl("jdbc:mysql://localhost:3306/atomikos_2");
mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
mysqlXaDataSource.setPassword("password");
mysqlXaDataSource.setUser("root");
mysqlXaDataSource.setPinGlobalTxToPhysicalConnection(true);
AtomikosDataSourceBean xaDataSource = new AtomikosDataSourceBean();
xaDataSource.setXaDataSource(mysqlXaDataSource);
xaDataSource.setUniqueResourceName("xads2");
return xaDataSource;
}
@Bean(name = "orderEntityManager")
public LocalContainerEntityManagerFactoryBean orderEntityManager() throws Throwable {
LocalContainerEntityManagerFactoryBean entityManager = new LocalContainerEntityManagerFactoryBean();
entityManager.setDataSource(orderDataSource());
entityManager.setJpaVendorAdapter(jpaVendorAdapter);
entityManager.setPackagesToScan("com.at.mul.domain.order");
entityManager.setPersistenceUnitName("orderPersistenceUnit");
Properties properties = new Properties();
properties.put("javax.persistence.transactionType", "JTA");
entityManager.setJpaProperties(properties);
return entityManager;
}
}
(CustomerRepository.java)
import org.springframework.data.jpa.repository.JpaRepository;
import com.at.mul.domain.customer.Customer;
public interface CustomerRepository extends JpaRepository<Customer, Integer> {
}
(OrderRepository.java)
import org.springframework.data.jpa.repository.JpaRepository;
import com.at.mul.domain.order.Order;
public interface OrderRepository extends JpaRepository<Order, Integer> {
}
I get a NullPointerException on when running this test:
import javax.transaction.Transactional;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import com.at.mul.MainConfig;
import com.at.mul.domain.customer.Customer;
import com.at.mul.repository.customer.CustomerRepository;
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = MainConfig.class)
@Transactional
public class CustomerRepositoryTest {
@Autowired
private CustomerRepository customerRepository;
@Test
public void testCustomerConfig() {
}
@Test
public void save() {
Customer c = new Customer();
c.setName("test-name");
c.setAge(30);
Customer cust = customerRepository.save(c);
Assert.assertNotNull(cust.getId());
}
}
The null object seems to be the transactionManager, so I suppose it's not properly injected. Relevant part of the stacktrace is here:
java.lang.NullPointerException
at org.hibernate.engine.transaction.internal.jta.JtaStatusHelper.getStatus(JtaStatusHelper.java:76)
at org.hibernate.engine.transaction.internal.jta.JtaStatusHelper.isActive(JtaStatusHelper.java:118)
at org.hibernate.engine.transaction.internal.jta.CMTTransaction.join(CMTTransaction.java:149)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.joinTransaction(AbstractEntityManagerImpl.java:1602)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.postInit(AbstractEntityManagerImpl.java:210)
at org.hibernate.jpa.internal.EntityManagerImpl.<init>(EntityManagerImpl.java:91)
at org.hibernate.jpa.internal.EntityManagerFactoryImpl.internalCreateEntityManager(EntityManagerFactoryImpl.java:345)
at org.hibernate.jpa.internal.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:313)
at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.invokeProxyMethod(AbstractEntityManagerFactoryBean.java:388)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean$ManagedEntityManagerFactoryInvocationHandler.invoke(AbstractEntityManagerFactoryBean.java:541)
at com.sun.proxy.$Proxy29.createEntityManager(Unknown Source)
at org.springframework.orm.jpa.EntityManagerFactoryUtils.doGetTransactionalEntityManager(EntityManagerFactoryUtils.java:285)
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:227)
at com.sun.proxy.$Proxy34.persist(Unknown Source)
at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:369)
The pom file is here:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.0.0.RC5</version>
</parent>
<groupId>com.at.mul</groupId>
<artifactId>mul-at</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>mul-at</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-snapshots</id>
<url>http://repo.spring.io/libs-snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<url>http://repo.spring.io/libs-snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.12.4</version>
</dependency>
<dependency>
<groupId>com.atomikos</groupId>
<artifactId>transactions</artifactId>
<version>3.9.3</version>
</dependency>
<dependency>
<groupId>com.atomikos</groupId>
<artifactId>transactions-jta</artifactId>
<version>3.9.3</version>
</dependency>
<dependency>
<groupId>com.atomikos</groupId>
<artifactId>transactions-hibernate3</artifactId>
<version>3.9.3</version>
<exclusions>
<exclusion>
<artifactId>hibernate</artifactId>
<groupId>org.hibernate</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
</project>
Full code is available on Github: https://github.com/fabiomaffioletti/mul-at I could not find any working example, and even after looking at the Spring blog article I cannot get it to work. Has anyone any hint?
Following the console log of spring boot for the customer connection:
2014-04-01 11:29:48.645 INFO 22368 --- [ main] c.atomikos.jdbc.AbstractDataSourceBean : AtomikosDataSoureBean 'xads1': init...
2014-04-01 11:29:48.645 WARN 22368 --- [ main] c.atomikos.jdbc.AbstractDataSourceBean : AtomikosDataSoureBean 'xads1': poolSize equals default - this may cause performance problems!
2014-04-01 11:29:48.672 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosDataSourceBean : AtomikosDataSoureBean 'xads1': initializing with [ xaDataSourceClassName=null, uniqueResourceName=xads1, maxPoolSize=1, minPoolSize=1, borrowConnectionTimeout=30, maxIdleTime=60, reapTimeout=0, maintenanceInterval=60, testQuery=null, xaProperties=[], loginTimeout=0, maxLifetime=0]
2014-04-01 11:29:48.809 INFO 22368 --- [ main] c.a.icatch.imp.thread.TaskManager : THREADS: using JDK thread pooling...
2014-04-01 11:29:48.837 INFO 22368 --- [ main] j.LocalContainerEntityManagerFactoryBean : Building JPA container EntityManagerFactory for persistence unit 'customerPersistenceUnit'
2014-04-01 11:29:48.857 INFO 22368 --- [ main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [
name: customerPersistenceUnit
...]
2014-04-01 11:29:48.919 INFO 22368 --- [ main] org.hibernate.Version : HHH000412: Hibernate Core {4.3.1.Final}
2014-04-01 11:29:48.920 INFO 22368 --- [ main] org.hibernate.cfg.Environment : HHH000206: hibernate.properties not found
2014-04-01 11:29:48.922 INFO 22368 --- [ main] org.hibernate.cfg.Environment : HHH000021: Bytecode provider name : javassist
2014-04-01 11:29:49.057 INFO 22368 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {4.0.4.Final}
2014-04-01 11:29:49.086 INFO 22368 --- [ main] c.atomikos.jdbc.AbstractDataSourceBean : AtomikosDataSoureBean 'xads1': getConnection ( null )...
2014-04-01 11:29:49.087 INFO 22368 --- [ main] c.atomikos.jdbc.AbstractDataSourceBean : AtomikosDataSoureBean 'xads1': init...
2014-04-01 11:29:49.145 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.145 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: calling getMetaData...
2014-04-01 11:29:49.166 INFO 22368 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
2014-04-01 11:29:49.172 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.172 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: calling getCatalog...
2014-04-01 11:29:49.174 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.175 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: calling getMetaData...
2014-04-01 11:29:49.175 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.175 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: calling createClob...
2014-04-01 11:29:49.177 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.177 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: close()...
2014-04-01 11:29:49.258 INFO 22368 --- [ main] o.h.h.i.ast.ASTQueryTranslatorFactory : HHH000397: Using ASTQueryTranslatorFactory
2014-04-01 11:29:49.428 INFO 22368 --- [ main] org.hibernate.tool.hbm2ddl.SchemaUpdate : HHH000228: Running hbm2ddl schema update
2014-04-01 11:29:49.428 INFO 22368 --- [ main] org.hibernate.tool.hbm2ddl.SchemaUpdate : HHH000102: Fetching database metadata
2014-04-01 11:29:49.428 INFO 22368 --- [ main] c.atomikos.jdbc.AbstractDataSourceBean : AtomikosDataSoureBean 'xads1': getConnection ( null )...
2014-04-01 11:29:49.428 INFO 22368 --- [ main] c.atomikos.jdbc.AbstractDataSourceBean : AtomikosDataSoureBean 'xads1': init...
2014-04-01 11:29:49.428 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.428 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: calling getAutoCommit...
2014-04-01 11:29:49.429 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.429 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: calling getMetaData...
2014-04-01 11:29:49.429 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.430 WARN 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: WARNING: transaction manager not running?
2014-04-01 11:29:49.430 INFO 22368 --- [ main] c.atomikos.jdbc.AtomikosConnectionProxy : atomikos connection proxy for com.mysql.jdbc.jdbc2.optional.JDBC4ConnectionWrapper@63f9f0f2: calling createStatement...
2014-04-01 11:29:49.431 INFO 22368 --- [ main] org.hibernate.tool.hbm2ddl.SchemaUpdate : HHH000396: Updating schema
2014-04-01 11:29:49.446 INFO 22368 --- [ main] o.hibernate.tool.hbm2ddl.TableMetadata : HHH000261: Table found: atomikos_1.customer
2014-04-01 11:29:49.446 INFO 22368 --- [ main] o.hibernate.tool.hbm2ddl.TableMetadata : HHH000037: Columns: [id, age, name]
2014-04-01 11:29:49.446 INFO 22368 --- [ main] o.hibernate.tool.hbm2ddl.TableMetadata : HHH000108: Foreign keys: []
2014-04-01 11:29:49.446 INFO 22368 --- [ main] o.hibernate.tool.hbm2ddl.TableMetadata : HHH000126: Indexes: [primary]
2014-04-01 11:29:49.447 INFO 22368 --- [ main] org.hibernate.tool.hbm2ddl.SchemaUpdate : HHH000232: Schema update complete
回答1:
I think the CMTTransaction
in the stack trace is the clue: Hibernate thinks you are in a container. I also think it might work if you just remove the javax.persistence.transactionType=JTA
property.
回答2:
Ofcource, you can remove javax.persistence.transactionType=JTA
and it will work.
But if you want to use JBOSS AS with own transaction manager (i like it more; there is a some bugs in atomicos which has fixed only customer version), you must put:
transactionType=JTA
Into persistance.xml property:
<property name="hibernate.transaction.jta.platform"
value="org.hibernate.service.jta.platform.internal.JBossAppServerJtaPlatform" />
Into spring-config:
<tx:jta-transaction-manager/>
<tx:annotation-driven/>
回答3:
https://blog.hanqunfeng.com/2016/12/21/spring-boot-study-jpa/#more
@Bean(name = "entityManagerFactory")
@DependsOn({"atomikosJtaPlatfom"}) //需要先注册atomikosJtaPlatfom
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
System.out.println("entityManagerFactory init");
LocalContainerEntityManagerFactoryBean entityManager = new LocalContainerEntityManagerFactoryBean();
entityManager.setJpaVendorAdapter(jpaVendorAdapter());
// entity package
entityManager.setPackagesToScan("com.example.model.ds1");
entityManager.setJtaDataSource(dataSource());
Properties properties = new Properties();
properties.put("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
properties.put("hibernate.show_sql", "true");
properties.put("hibernate.format_sql", "true");
//jta设置
properties.put("hibernate.current_session_context_class", "jta");
properties.put("hibernate.transaction.factory_class", "org.hibernate.engine.transaction.internal.jta.CMTTransactionFactory");
//这里指定我们自己创建的AtomikosJtaPlatfom
properties.put("hibernate.transaction.jta.platform","com.example.AtomikosJtaPlatfom");
entityManager.setJpaProperties(properties);
return entityManager;
}
来源:https://stackoverflow.com/questions/22779155/spring-boot-spring-data-jpa-atomikos-multiple-databases-configuration