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Change Java Spring Boot Bean while runtime

Hello fellow developers,
i created a library using the Spring boot framework.
This library is creating a dynamic database connection using #Beans where i create a "data" Bean which holds the unlimited Datasource beans provided by a Postgresql db. At the end i wanted to have a dynamic db connection which could be triggered from outside to change the db i want to connect to. The information of the different databases where stored as mentioned inside of a postgres. This is loaded at the application start into this bean. My Problem is, that i'm not able to switch between the different Datasource beans. Spring boot is creating them, but it seems like it's not possible to change the bean started at runtime of the application which only holds one of the unlimited Datasources... So also after a retriggering of the creation of the original bean it still uses the old datasource.
Is there a way to use the beans from spring boot and change them on runtime?
Regards,
Andreas

I believe you are asking for DB multitenancy support where tenants information is stored in a Postgres DB.
Configuring the persistent layer for multi-tenancy support involves configuring:
Hibernate, JPA and Datasources properties
Datasources beans
Entity manager factory bean
Transaction manager bean
Spring Data JPA and annotation-driven transactions
I recently blog about Multi-tenant applications using Spring Boot, JPA, Hibernate and Postgres and although the tenants data is stored in a yml "properties" file, it shouldn't be difficult to convert it to read tenant data from a DB. I think it would be a starting point for what you would like to accomplish.

Spring MVC - Distributed Database Transaction

I'm currently developing a web application using Spring MVC (without Maven).
What I need is to create a distributed transaction between two local databases, so that the code will update all of them in (theoretically) a 2phase commit.
Now, since I'm doing it for a school project, I'm in a simple environment which needs only to take a row from a table in one db and put it in a table on the other db, of course atomically (theoretically, such a transaction should be distributed because I'm using two different databases and not only one).
My question is, how can I deploy a Spring bean that firstly connects to both MySQL databases and then does that distributed transaction? Should I use some external library or could I achieve all with only using the Spring framework? In which case, could you please kindly link me an example or a guide to do this?
Thank you in advance for your help :)

Spring has an interface PlatformTransactionManager which is an
abstraction And it has many implementations like
DataSourceTransactionManager,HibernateTransactionManager etc.
Since you are using distributed transactions so you need to use
JTATransactionManager
These TransactionManagers provided by spring
are wrapper around the implementations provided by other frameworks
Now in case of JTA , you would be using either an application server
or a standalone JTA implementation like Atomikos
Following are the steps :-
Configure Transaction Manager in spring using application server
or standalone JTA implementation
Enable Transaction Management in spring
And then configure in your code the #Transactional annotation above
your method
Have a look at following links
http://docs.spring.io/spring/docs/current/spring-framework-reference/html/transaction.html
http://www.byteslounge.com/tutorials/spring-jta-multiple-resource-transactions-in-tomcat-with-atomikos-example

Multiple Data Source using Spring JPA

I am building a stand alone java application using Spring JPA frame
work. I am able to access the DB in below scenario: if I give the
DB details in application.properties file as
spring.datasource.url=******** spring.datasource.username=******
spring.datasource.password=******
then it's working properly.
but I have to create two DB connections in the same application so,
I changes the names as below
spring.Datasource1.url=********* spring.Datasource1.username=******
spring.Datasource1.password
spring.Datasource2.url=************ spring.Datasource2.username=****
spring.Datasource2.password=*****
then it's not working.
Can you please provide the solution for it?
I have uploaded my code base in below location.
https://github.com/nagtej/MultipleDataSource

This might be helpful to you http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#howto-two-datasources
Also, to connect to multiple data sources you would need to manually configure a DataSource, EntityManagerFactory and JpaTransactionManager.
For this, you can have a look at code placed at https://github.com/spring-projects/spring-data-examples/tree/master/jpa/multiple-datasources
Another good example for this is shared at http://xantorohara.blogspot.com.au/2013/11/spring-boot-jdbc-with-multiple.html

Spring Boot and Spring Data application with multiple DataSources created in runtime

I am developing a Spring Boot application that uses Spring Data JPA and will need to connect to many different databases e.g. PostreSQL, MySQL, MS-SQL, MongoDB.
I need to create all datasources in runtime i.e. user choose these data by GUI in started application:
-driver(one of the list),
-source,
-port,
-username,
-password.
And after all he writes native sql to choosen database and get results.
I read a lot of things about it in stack and spring forums(e.g. AbstractRoutingDataSource) but all of these tutorials show how to create datasources from xml configuration or static definition in java bean. It is possible to create many datsources in runtime? How to manage transactions and how to create many sessionFactories? It is possible to use #Transactional annotation? What is the best method to do this? Can someone explain me how to do this 'step by step'?

Hope it's not too late for an answer ;)
I developed a module which can be easily integrated in any spring project. It uses a meta-datasource to hold the tenant-datasource connection details.
For the tenant-datasource an AbstractRoutingDataSource is used.
Here you find my core implementation using the AbstractRoutingDataSource.
https://github.com/Dactabird/multitenancy
Here is an example to show how to integrate it. https://github.com/Dactabird/multitenancy-sample
In this example I'm using H2 embedded db. But of course you can use whatever you want.
Feel free to modify it for your purposes or to ask if questions are left!

Dynamic configuration in a java/camel/spring/jpa application

I have written an application using java, camel, spring, shiro, c3p0 and jpa.
This application needs to connect to some web services and some db and it has now a static configuration using classic spring propertyplaceholders and .prop property files.
I inject properties in java classes using #Value annotations and I define datasources using spring with ${} placeholders.
In the configuration there are url,username,password for web services and database,url,username,password for datasource.
Now I need to do a dynamic/multi tenant configuration. I mean that each "customer" can have his set of passwords and that these login/passwords can change over time.
Using shiro I can add to the Subject some data, so I can add current properties to it and get them where I need.
But how can I continue to use #value annotations?
And, most important question, how can I change datasources parameters at runtime?
I see in c3p0 documentation that using getConnection(username,password) with a new pair of username and password creates a new pool and close the old. But I do not use getConnection because only the EntityManager uses datasource.
Please help me!
Thanks,
Mario
After a lot of searching I think I can do in this way:
for properties use DynamicCombinedConfiguration from commons configuration, but I do not know how to tell it to read the tenant id from Shiro Subject
for JPA use AbstractDataSource from spring, but again I do not know if I can read the tenant id from Shiro Subject
Can you tell me if I am pointing in the right direction?
Thanks again,
Mario