Skip to main content

Red Hat JBoss Fuse - Integrating Database, Java Bean and Restful Services in EAP, Java DSL with CDI

We have talked about how to start develop application in EAP with Java DSL, and most interestingly how to utilize the CDI framework in JavaEE. And in this post we are going to take that example a bit more further, show you how to integrate with Databases, Java beans in the application, creating a servlet and lastly setup a Restful webservice.

For this currency exchange project, I have store the exchange rate in the h2 database. What we are going to do is to display the entire exchange rate on the webpage provided by a restful web service and provide a servlet that takes in the amount of money and the currency to exchange to, send them back to server, calculated and return the result. So here are the things I am going to do

  • Database
  • Java Bean
  • Servlet
  • Restful Web Services

Of course we want to use the datasources in EAP. So first thing first, create the datasource in EAP. Make sure you started the JBoss EAP. Go to Configuration, select Connector and then to datasources.

  • Name :MyCamelDS
  • JNDI Name: java:jboss/datasources/MyCamelDS

 Select the Driver we are going to use, and it's h2 this case,

Enter the

  • Connection URL: jdbc:h2:file:~/h2/fuseoneap;AUTO_SERVER=TRUE
  • Username: sa
  • Password: 

Change the min and max pool size to 1 and 10. And then enable the MyCamelDS datasource.

And there we are, datasource ready!
We can then use the CDI framework to lookup datasource in JNDI. So create a CDI Producer, in CDI, the producer produce an object that can be injected which we are going later inject the datasource into our camel context.

public class DatasourceProducer {

  @Resource(lookup= "java:jboss/datasources/MyCamelDS")
  DataSource dataSource;

  public DataSource getDataSource() {
    return dataSource;  }


You will be surprised on how easy it really is to use it in Camel, because it's done. Now in our RouteBuilder class, we are going select every single exchange rate in the database. We are going to use the SQL component in Camel, provide the SQL, and then provide the datasource name we named in the producer we created. 

Lastly we are going to transform the resultset in JSON format, using the built-in transformation components in Camel.  

  .to("sql:select * from currencyexchange?dataSource=MyCamelDS")

That's it!

Java Bean
First thing, create a Java class that has a method takes in amount of money and currency to exchange. And on top of the class, place the @Name annotation, this will allow the bean we created to accessible through the EL. And we can lookup the bean from Camel.

  public class CurrencyConvertor {
    public double convertUSD(double amt, ArrayList<Map<String, Object>> data){
      Double rate = (Double)data.get(0).get("rate");
      return amt*rate;


To use it in the Camel route, just use the bean components in Camel. 

  .log("Got currency: ${headers.amt} and amt${headers.currency} ")
      .to("sql:select * from currencyexchange where currencycode = :#currency?dataSource=MyCamelDS")
      .log("exchange rate ====> ${body[0][rate]}")
    .log("nothing to lookup")
     .transform().constant("nothing to lookup");

We need to setup the Servlet, under webapp, create the WEB-INF/web.xml file. Right click on Deployment Descriptor and choose Generate Deployment Descriptor Stub. It will create an empty web.xml file for you.

Add the servlet setting in the web.xml and publish it 



Once it's done, we can then use the Servlet component in Camel, it will publish a servlet endpoint through the Servlet we set earlier.


Restful Web Service
The Restful web services needs to have the CamelHttpTransportServlet setup too, since we have already done that in Servlet, all we have to do is to builds Rest endpoints as consumers in Rest DSL. And then configure it to servlet.



That's all you have to do. You can find the entire project code here.


Popular posts from this blog

JBoss EAP 6 - 效能調校 (一) DataSource 的 Connection Pool

效能沒有什麼Best Practice, 反正能調整的就那些。 通常,一個程式的效能大概有70-80% 都跟程式怎麼寫的其實比較有關係。

最近我最疼愛的小貓Puji 因為膀胱結石開刀的時候過世了,心情很差請原諒我的口氣沒有很好,也沒有心情寫部落格。

Puji R.I.P.



JBoss 的 SubsystemDatasource WebWeb Service EJB Hibernate JMSJCAJVM 調校OS (作業系統)

先來看一下 DataSource Subsystem, DataSource 的部分主要是針對Connection Pool 做調校。

通常,程式都會需要跟資料庫界接,電腦在本機,尤其是在記憶體的運算很快,但是一旦要外部的資源連接,就是會非常的耗資源。所以現在的應用程式伺服器都會有個Pool 放一些先連接好的 資料庫connection,當程式有需要的時候就可以馬上提供,而不用花那些多餘的資源去連接資料庫。

這就是為什麼要針對Connection Pool 去做調校。

以下會討論到的參數,都是跟效能比較有關係,Datasource 還有很多參數,像是檢核connection 是否正確的,我都不會提到。如果你追求的是非常快速的效能,那我建議你一個檢核都不要加。當然,這樣就會為伺服器上面執行的程式帶來風險。這就是你要在效能與正確,安全性上面的取捨了。 (套句我朋友說的話,不可能又要馬兒好,又要馬兒不吃草的..)

最重要的調校參數就是 Connection 的 Pool 數量。(也就是那個Pool 裡面要放幾條的connection.) 這個參數是每一個應用程式都不一樣的。


Connection Pool 最少會存留的connection 數量


Connection Pool 最多可以開啓的 connection 數量


事先將connection pool 裡面建立好min-pool-size 的connection.

我的建議是觀察一下平常程式要用到的量設定為 min-pool-size 。

Red Hat Fuse - Announcing Fuse 7 Tech preview 3 release.

Red Hat Fuse 7.0 technical preview three is out today! On the pathway to become one of the best cloud-native integration platform, Fuse gives developer freedom to choose how they want to develop the integration solution, where they want to deploy it and capabilities to address new integration personas that do not have development experience.
By supporting the three major runtime, developer is free to work on the runtime of their choice.By supporting standalone and cloud deployment, it simplifies the complexity to distinguish between these environments, allowing application to deploy freely among the environment of your choice. All levels of developers are welcome, you can either dive deep into creating customize complex integration logic, or using the new low code platform to quickly build a simple integration. In this Tech Preview release you get it all.
Fuse StandaloneSpring-boot for microserviceKaraf 4 for OSGi loverJBoss EAP for JavaEE developersFuse on OpenShiftPlugins for easy co…

The rise of Agile Integration, Integration is not DEAD nor LAME!

I wanted to blog about this for a very long time, but because of work and being too lazy to turn on my laptop on the weekends, now I finally have a couple of hours to sit down and start blogging.

"Integration is DEAD."
"No, no, let's talk about microservice!!"
"What is that again? Integration, you mean SOA? It's lame... ".

These makes the majority of the percentage when I talk about Integration. In fact, if you happen to be in any the software conference, you see the rooms full when it's about "container" and "microservice." I understand the nature of a developer, always seeking for the latest and greatest technology out there. BUT!! In my opinion, I don't think Integration is going AWAY if you containerize your application. Neither does it will DISAPPEAR in a microservice architecture. In fact, Integration just gets more complicated and tricky when you try to break an application into smaller pieces and have them runni…