TDDD05 EJB Lab(Part of slides reused from Mikhail’s)

Lu Lilu.li@liu.se

Agenda

• EJB brief introduction• Practical hints

Why EJB

• EJBs is a powerful component model for building distributed, server-side, and Java-based enterprise application components.

• Code reuse by middleware service, such as object life-cycle management, resource (beans, database connection) mapping etc.

EJB architecture

EJB architecture

EJB architecture

Connect Glassfish to Database

• Configure MySQL database• Copy driver to Glassfish directory• Configure a connection pool (For example

“TDDD05_MySQL”), and do a ping test• Configure JDBC resource (For example

“TDDD05_JDBC”) to use the connection pool (“TDDD05_MySQL”)

Create an JPA to use database

• JPA is a kind of EJB for interaction with database.

• Configure persistence.xml under META-INF folder, if no such xml file found, create one.

Create an Stateless Bean

• Create a EJB project• Add library appserv-rt.jar, j2ee.jar

Create an Stateless Bean

• Create an interface

Create an Stateless Bean

• Create an implementation

Deploy EJB

• Export jar• Start Glassfish• Copy jar file into the autodeploy directory• Check the file generated• There is another way to deploy. (Covered

later)

JNDI lookup

JNDI Application

Dependency injection

DI Application

DI Application

• Deployment(Glassfish_Home)/bin/asadmin deploy –

retrieve . Ex1-ee.ear• Execution

(Glassfish_Home)/bin/Appclient –client ./ex1-eeClient.jar –mainclass client.AppClient

Facade

Summary

• You needs a MySQL with a designed table.• You needs to make a Glassfish to know the

connection to your MySQL• You needs a JPA to use the connection and

interact with MySQL• You needs a Stateless session bean to use the

JPA.

Summary

• You needs to declare an interface to expose functionality to external clients.

• You needs a JNDI lookup client which can run independently

• You needs a DI client in connection with EJB (Two components are package in EAR project), to be deployed in Glassfish and invoke them by Appclient.

Some suggestions

• Try to understand how different components interact with each other at implementation level.

• Do a thorough unit testing before integrating all components together

• Today’s lesson covers most but not all steps needed for lab 2. Feel free to change some steps if you think it is necessary.

Questions?