Spring boot common application properties - spring-boot

Question

Spring boot application properties needs to follow convention from https://docs.spring.io/spring-boot/docs/current/reference/html/common-application-properties.html when we use any DB like cassandra/mongo. In case if we want to declare our own properties for DB setup instead of spring-boot convention, what are all the steps we need to do for setting up DB?

Answer 1

You can do this: Spring boot - custom variables in Application.properties
or you can just create your own property in your application.properties file like:
my.property.someDb.hostname=http://wherever.comand then reference to it in your code like:
#Value("${my.property.someDb.hostname}")
private String someDbHostname;
Update 1:
If you want to create the MongoDb with your own properties you have to define the right Java Beans in an #Configuration file. For MongoDB it could look like the following:
#Configuration
public class MyMongoConfig extends AbstractMongoConfiguration{
#Value("${my.property.someDb.hostname}")
private String someDbHostname;
#Value("${my.property.someDb.myOwnPortDefinition}")
private int myOwnPortDefinition;
#Value("${my.property.someDb.myDatabasename}")
private String myDatabasename;
#Override
protected String getDatabaseName() {
return myDatabasename;
}
#Override
#Bean
public Mongo mongo() throws Exception{
return new MongoClient(someDbHostname, myOwnPortDefinition );
}
#Bean
public MongoTemplate mongoTemplate() throws Exception{
return new MongoTemplate(mongo(), getDatabaseName());
}
}

Answer 2

These are the essential steps you need in order to get a data source like Jdbc, mongodb set up in Spring Boot
Need a #Configuration class that has transaction management enabled
on it
Read the environment properties for the datasource i.e. dataSource
url, username, password etc.
Create beans for datasource, session factory, transaction manager
etc.
Once all of the above setup, use this #Configuration in your
consumer to initialize the spring application context
Here are some snippets of wiring mongodb datasource in spring boot
DataSourceConfiguration.java
#Configuration
#EnableTransactionManagement
#ComponentScan(basePackages = {"com.example.xyz"})
public class DatabaseEntityConfiguration {
public static final String DATABASE_ENTITY_DATA_SOURCE = "databaseDataSource";
public static final String DATABASE_HIBERNATE_PROPERTIES = "databaseHibernateProperties";
public static final String DATABASE_ENTITY_SESSION_FACTORY = "databaseSessionFactory";
public static final String DATABASE_ENTITY_TRANSACTION_MANAGER = "databaseTransactionManager";
public static final String DATABASE_ENTITY_DB_CONFIG_DAO = "dmdatabaseDbConfigDao";
public static final String DATABASE_ENTITY_DB_CONFIG_SERVICE = "dmdatabaseDbConfigService";
private static final String ENTITY_PACKAGE = "com.example.xyz.database.entity";
#Autowired
private org.springframework.core.env.Environment environment;
#Bean(name = DATABASE_ENTITY_DATA_SOURCE)
public DataSource databaseEntitydataSource() throws PropertyVetoException {
// mongodb properties
String driverClass = environment.getProperty("databaseEntity.mongodb.driverClassName");
String mongodbUrl = environment.getProperty("databaseEntity.mongodb.dmdatabaseDataSource.url");
String user = environment.getProperty("databaseEntity.mongodb.dmdatabaseDataSource.username");
String password = environment.getProperty("databaseEntity.mongodb.dmdatabaseDataSource.password");
Preconditions.checkArgument(StringUtils.isNotBlank(driverClass), "The property mongodb driverClass must not be null or blank");
Preconditions.checkArgument(StringUtils.isNotBlank(mongodbUrl), "The property mongodb mongodbUrl must not be null or blank");
Preconditions.checkArgument(StringUtils.isNotBlank(user), "The property mongodb user must not be null or blank");
Preconditions.checkArgument(StringUtils.isNotBlank(password), "The property mongodb password must not be null or blank");
dataSource.setDriverClass(driverClass);
dataSource.setmongodbUrl(mongodbUrl);
dataSource.setUser(user);
dataSource.setPassword(password);
return dataSource;
}
#Bean(name = DATABASE_ENTITY_SESSION_FACTORY)
public AnnotationSessionFactoryBean databaseEntitySessionFactory() throws PropertyVetoException {
AnnotationSessionFactoryBean annotationSessionFactoryBean = new AnnotationSessionFactoryBean();
annotationSessionFactoryBean.setDataSource(databaseEntitydataSource());
annotationSessionFactoryBean.setPackagesToScan(ENTITY_PACKAGE);
annotationSessionFactoryBean.setAnnotatedClasses(DBConfig.class);
annotationSessionFactoryBean.setHibernateProperties(databaseEntityHibernateProperties());
return annotationSessionFactoryBean;
}
#Bean(name = DATABASE_ENTITY_TRANSACTION_MANAGER)
public HibernateTransactionManager databaseEntityTransactionManager() throws PropertyVetoException {
HibernateTransactionManager transactionManager = new HibernateTransactionManager();
transactionManager.setSessionFactory(databaseEntitySessionFactory().getObject());
return transactionManager;
}
}