Spring Boot Persistence - spring

Question

How does SpringBoot fetch the DataSource configuration from application.properties file.
Would the below configuration persist the entity ?
Module 1 contains Config file and application.properties file
Module 2 contains Repository and Service File
I have not configured any File with #Repository annotation as of now.
contextRepository.saveAndFlush(test);
Spring Boot Configuration class below:
#EnableSwagger2
#SpringBootApplication
#ComponentScan(basePackages={"ch.service"})
public class MyCodeConfiguration extends SpringBootServletInitializer {
//Module1
package ch.service.config;
#Bean
#Primary
#ConfigurationProperties(prefix = "spring.datasource")
public DataSource realDataSource() {
return DataSourceBuilder.create().build();
}
#Bean
#ConditionalOnMissingBean(PlatformTransactionManager.class)
public DataSourceTransactionManager transactionManager() {
DataSourceTransactionManager transactionManager = new DataSourceTransactionManager(realDataSource());
return transactionManager;
}
}
Service Class below.
//Module2
package ch.service.config;
#Service
public class CodeServiceImpl implements CodeService {
#Autowired
private ContextRepository contextRepository;
#Transactional
public void persistValues(Testbean test){
contextRepository.saveAndFlush(test);
}
}
Repository class below
//Module2
package ch.service.config.dao;
public interface ContextRepository extends JpaRepository<MyContext, Long> {
}
Error Below:
***************************
APPLICATION FAILED TO START
***************************
Description:
Parameter 0 of method transactionManager in org.springframework.boot.autoconfigure.transaction.jta.BitronixJtaConfiguration required a bean of type 'javax.transaction.TransactionManager' that could not be found.
- Bean method 'narayanaTransactionManager' not loaded because #ConditionalOnClass did not find required classes 'com.arjuna.ats.jta.UserTransaction', 'org.jboss.tm.XAResourceRecoveryRegistry'
Action:
Consider revisiting the conditions above or defining a bean of type 'javax.transaction.TransactionManager' in your configuration.

Answer 1

When you use Spring Boot you can use the following predefined DB configuration keys in application.properties to automatically configure the database.
spring.datasource.url=jdbc:mysql://localhost/test
spring.datasource.username=dbuser
spring.datasource.password=dbpass
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
Your rest of the code looks good. It should persist the data
To fix the Exception you are getting you have to have a Transaction Manager in your config.
#Bean
public PlatformTransactionManager transactionManager() {
return new JpaTransactionManager();
}
Ref : https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-sql.html

Answer 2

If your project has a data starter, for example :
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
And you want it to be connected to a non embedded database, you must setup the configuration in application.properties with spring.datasource.* keys
DataSourceProperties will pick up the configuration
All the spring boot key are here