Presentation of Enterprise Service Bus(ESB) and. Apache ServiceMix. Håkon Sagehaug

Transcription

1 Presentation of Enterprise Service Bus(ESB) and Apache ServiceMix Håkon Sagehaug

2 Outline Enterprise Service Bus, what is is Apache Service Mix Java Business Integration(JBI) Tutorial, creating a HTTP file upload application

3 Enterprise Service Bus(ESB) As the name suggests make use of the bus concept No need for point-to-point communication All the the communication is done through the bus Leads to easier integration of new functionality or new software the existing infrastructure

4 ESB

5 Requirements for ESB Needs to be able to route the requests to the appropriate service Be able to encapsulate the functionality of the end services. Reliability, needs to be stable Security, authentication of user, message integrity

6 Apache ServiceMix Open source implementation of ESB concept. Is mostly based on something called Java Business Integration(JBI)

7 ServiceMix Architecture

8 Java Business Integration(JBI) A specification for sending messages between plugins by using a mediate message router The model used is adopted from the WSDL 2.0 spec messages exchange pattern In-Only, Robust In-Only, In-Out, In-Optional-Out Messages, called Normalized Message(NM), is delivered to Normalized Message Router(NMR). The NM is XML-based

9 Components in JBI Binding components, used for convert from one protocol to a normalized message or vica versa Service Engines, provides some logic for handling the Normalized Message. E.g. route it, run a BPEL process, host a web service

10 JBI Consumer vs. JBI Provier

11 Tutorial Writing a http upolad app Creating a service that will upload a file to servicemix Using a html form for uploading the file The file is given to a http-consumed-su in servicemix Then sent as a Normalized Message to the Normalized Message Router A class the receives the file and writes it to the file system. If time transform from name.odt -> name.pdf name.wiki

12 JBI packing of a service Many service units, these a re components that does the actual work One service assembly, that holds all the service-units together

13 Creating maven top project Maven to create the project from this pom.xml <?xml version="1.0" encoding="utf-8"?> <project xmlns=" xmlns:xsi=" xsi:schemalocation=" <modelversion>4.0.0</modelversion> <groupid>org.apache.servicemix.examples</groupid> <artifactid>http-example</artifactid> <version>1.0-snapshot</version> <packaging>pom</packaging> <name>simple HTTP Upload example</name> <url> </project> execute: mvn clean install

14 Creating http-consumer-su Su stands for service unit Making the maven project that contains the http consumer mvn archetype:create -DarchetypeGroupId=org.apache.servicemix.tooling -DarchetypeArtifactId=servicemix-http-consumer-service-unit -DgroupId=org.apache.servicemix.examples -DartifactId=http-consumer-su servicemix-http-consumer-service-unit = name of the type of project we want to create -DgroupId = org.apache.servicemix.examples = our name of the group of the new project -DartifactId = http-consumer-su = name of this component

15 After creating http-consumer-su We have a pom.xml describing the project all dependencies and stuff like that src/main/resourcses/ which contains a file called xbean.xml, that we'll be configurating the service with

16 Look at the xbean.xml file <beans xmlns:http=" xmlns:ex=" < service="ex:httplistener" endpoint="listenerendpoint" locationuri=" defaultmep=" targetservice="ex:httphandler" marshaler="#marshaler" /> <bean id="marshaler" class="org.apache.servicemix.jbi.httpmarshaler" /> </beans> The role of the HTTPMarshaler, is to get the request from the client, extract the file and, make a NM and send it to the NMR, to the endpoint.

17 Into eclipse Once created the project it's nice to be able to import it into Eclipse, when starting programming. mvn eclipse:clean eclipse:eclipse Then import the project into Eclipse as a excisting Eclipse project Must specify the M2_REPO classpath variable in Eclipse, to your local maven repo, typically located at ~/.m2/repository

18 Making the HttpMarshaller Superclass is DefaultHttpConsumerMarshaler We are going to override two methods createexchange(), that handles incomming messages, parse the file comming from the html form sendout(), reponse back to the client

19 Creating the http-handler-su Going to handel the data from out httpconsumer-su mvn archetype:create -DarchetypeGroupId=org.apache.servicemix.tooling -DarchetypeArtifactId=servicemix-bean-service-unit -DgroupId=org.apache.servicemix.examples -DartifactId=http-handler-su Additional to the two folders we had created for us last time, we have a new one called src/main/java, where we place our java files

20 xbean.xml for the http-handler-su <?xml version="1.0" encoding="utf-8"?> <beans xmlns:bean=" xmlns:ex=" <bean:endpoint service="ex:httphandler" endpoint="handlerendpoint" bean="#extractorbean"/> <bean id="extractorbean" class="org.apache.servicemix.jbi.handlerbean" /> </beans>

21 HandlerBean.java Interface: org.apache.servicemix.messageexchangelistener We implement onmessageexchange(messageexchange arg0) Is responsible for handling incomming messages In this case, gets the file from the NM, writes it to the filesystem.

22 http-handler-sa Using maven to this also mvn archetype:create -DarchetypeArtifactId=servicemix-serviceassembly -DarchetypeGroupId=org.apache.servicemix.tooling -DgroupId=org.apache.servicemix.examples -DartifactId=http-upload-sa

23 pom.xml for the http-upload-sa <project>... <dependencies> <dependency> <groupid>org.apache.servicemix.examples</groupid> <artifactid>http-consumer-su</artifactid> <version>1.0-snapshot</version> </dependency> <dependency> <groupid>org.apache.servicemix.examples</groupid> <artifactid>http-handler-su</artifactid> <version>1.0-snapshot</version> </dependency> </dependencies>... </project>

24 HTML client Create a HTML form like this <form action=" method="post" enctype="multipart/form-data"> Select file: <input type="file" id="file" name="file"></input> <br /><br /> <input type="submit"></input> </form>

25 Depoly in ServiceMix After we've created the service assemply we''ve got a http-upload-sa/target/http-upload-sa-1.0- SNAPSHOT.jar) This jar file we'll move into the hotdeploy folder of servicemix, then servicemix will take care of deploying the service