JBoss AS 7 - development basics

JBOSS AS 7 DEVELOPMENT BASICS WITH JAVA EE

Gabriele Falace

INSTALLATION AND INITIAL

SETUP

JBoss AS 7 | Gabriele Falace

Introduction

• JBoss Application Server 7 is a Java EE compliant

application server

• Provides the runtime to any portable Java EE application.

• Other than basic containers (web and EJB) it offers a

whole set of components supporting extra features such

as REST services, security and more.


Components overview

• Here are some components shipped with JBoss AS 7

• Hibernate 4 (for Object Relational Mapping)

• RESTEasy (for developing REST services)

• Mojarra (a standard implementation of JSF)

• Infinispan (a container managed Cache service)

• Apache CXF (for developing SOAP services)

• Arquillian (testing framework)


Initial setup To start using JBoss

• Set the JBOSS_HOME environment variable to the JBoss installation’s root directory (where it has been decompressed).

• Make sure that JAVA_HOME and MAVEN_HOME variables are correctly pointing Java and Maven installation directories, respectively

• Add a user with jboss-7.x.x.x\bin\add-user.bat

• Choose a)

• Realm let ManagementRealm

• User type your own username

• Password type your own password

• Start the server with the script jboss-7.x.x.x\bin\standalone.bat

• Pointing the browser to http://localhost:8080 we can test that the server has started correctly and we can then access the console (also reachable at http://localhost:9990 )


http://localhost:8080/

http://localhost:9990/

Initial setup


Initial setup

• In addition to the console, administration tasks can be

accomplished via a command line interface (CLI) started

with the script

jboss-7.x.x.x\bin\jboss-admin.bat –connect

• JBoss tools for Eclipse:

http://marketplace.eclipse.org/content/jboss-tools-kepler

will enhance Eclipse with several add-ons which will

streamline Enterprise Application development with

JBoss.









DATASOURCES


Configuring a Datasource

• The ‘safest’ way to create a Datasource is creating a so-

called Module, through the following procedure (i.e.

MySQL)

1. Browse to the following directory: jboss-as-7.1.0.Final\modules\com

and create the following directory: mysql\main

obtaining jboss-as-7.1.0.Final\modules\com\mysql\main

2. In such location, copy the MySQL java driver’s Jar, that

should be named something similare to: mysql-connector-java-5.1.27-bin.jar


Configuring a datasource

3. In the same directory create the file module.xml with the following content: <module xmlns="urn:jboss:module:1.0" name="com.mysql">

<resources>

<resource-root path="mysql-connector-java-5.1.27-bin.jar"/>

</resources>

<dependencies>

<module name="javax.api"/>

</dependencies>

</module>

4. In the directory: jboss-as-7.1.0.Final\standalone\configuration open the standalone.xml file

Note: it is also easily accessible in Eclipse in Filesets > Configuration File under the ‘Servers’ tab.


Configuring a Datasource

5. In the standalone.xml insert • Inside the <drivers> tag, add the following

<driver name="mysql" module="com.mysql"/>

• Inside the <datasources> tag, add the following <datasource jta="true" jndi-name="java:/mydb" pool-name="my_pool" enabled="true" use-java-context="true" use-ccm="true">

<connection-url> jdbc:mysql://localhost:3306/world

</connection-url>

<driver>mysql</driver>

<security>

<user-name>root</user-name>

<password>root</password>

</security>

<statement>

<prepared-statement-cache-size>100</prepared-statement-cache-size>

<share-prepared-statements>true</share-prepared-statements>

</statement>

</datasource>


Using a DataSource

6. The DataSource is now ready to be used. In our

persistence.xml file, we can point the datasource, as

shown in the following element:

<jta-data-source>java:/mydb</jta-data-source>


HORNETQ AND JMS


JMS Queues and HornetQ

In order to utilize the HornetQ messaging middleware, one

needs to use the standalone-full.xml configuration file

To start the ‘full’ server in Eclipse

1. Double click on the server

2. Under ‘General Information’ click on ‘Runtime Environment’

3. In the ‘Configuration file’ box, choose standalone-full.xml

The config file already contains proper settings to use the

system. In the following, let’s see what is specified in that

file


JMS Queues and HornetQ

• To declare a queue, so that it is deployed on the server, some

configuration inside the config file has to be done.

• Inside the <hornetq-server> element, insert the following

<jms-destinations>

<jms-queue name="testQueue">

<entry name="queue/test"/>

<entry name="java:jboss/exported/jms/queue/test"/>

</jms-queue>

<jms-topic name="testTopic">

<entry name="topic/test"/>

<entry name="java:jboss/exported/jms/topic/test"/>

</jms-topic>

</jms-destinations>


An MDB processing JMS messages


A JMS sender


INFINISPAN


INFINISPAN

• It’s JBoss’ cache, also used by several other modules

• Infinispan libraries, located in JBOSS_HOME/modules/org/infinispan

must be visible to the project (i.e. add to Build path)

• In order to get them exported when a deployable artifact is created,

the following line must be appended to the Manifest.MF file

Dependencies: org.infinispan export

• Now we can use JBoss’ Infinispan cache subsystem, by injecting the

CacheContainer through the @Resource annotation


INFINISPAN


CLUSTERING


Clustering - intro

High availability

• Obtained through components replication (EJBs, HTTP session) across several nodes/instances

• Namely, each physical machine is a ‘Node’ on which several JBoss AS instances may run

• But replication requires keeping replicated objects coherent and therefore it can affect scalability (especially in case of stateful objects)

• When Stateful EJBs are replicated, these get activated/passivated after each invocation and the state is managed through the infinispan cache.


Clustering – application side

• On the application side, a couple of operations need to be

performed

1. In the web.xml file, adding the element <distributable/>

right before the closing </web-app> tag

2. Annotate the EJBs that we want to be replicated (or clustered) with the @Clustered annotation from the

org.jboss.ejb3.annotation package


Clustering – configuring

• Moreover, we need to

• Install N JBoss instances, decompressing to separate folders

• Install an Apache HTTPD server, to act as a load balancer

• Install into httpd the mod_cluster module

• On the JBoss website there’s an http server with mod_cluster

already bundled

• Pay attention to other applications that possibly could use same

ports used by JBoss, thus interfering with the server behavior

• On windows, use the netstat –noa

command to check what ports are being used by which process


Clustering – configuring

• Start each instance with the standalone-ha.xml config file

• Except the first instance, it is also needed to set port

offsets, not to make instances collide on ports acquisition

standalone.bat -Djboss.node.name=jb2 --server-config=standalone-ha.xml -Djboss.socket.binding.port-offset=100

• Correct deployment can be checked by verifying the

presence of a file named projectName.ear.deployed in the

deployment directory


Clustering - failover

At this point, we can start our mod_cluster enabled httpd server: JBoss instances currently running will automatically register with the httpd server, as a load balancer (a message will appear in the instances console).

When we turn one of the JBoss instances down, httpd will automatically manage the failover forwarding requests to an active instance, in a way totally transparent to the application.

The application needs to be accessed by pointing the browser to the address:port where the HTTP Server is listening.


APPLICATION SECURITY


Security – basic concepts

Main security concerns are

• Authentication (Principal, a.k.a. Users)

• Authorization (Roles, operations allowed on which resources)

EJB 3 allow to profile access to methods based on roles, by annotating such methods: @PermitAll any caller can execute this method

@RolesAllowed("FOO") this method is executed only id the caller has a role= FOO

@DenyAll this method is not callable by anyone


Security domains

The EJB needs to know

1. Where to read users/roles definitions, against which validate

the identity of the user currently logged in.

2. The user currently logged in, itself.

The solution to (1) is given by security-domains inside the config

file standalone.xml

Each security-domain define rules for authentication and

authentication providers where credential are stored (properties

files, databases, LDAP servers, etc…)

In the following slide it is shown the default security domain

(other), which uses a couple properties files included in JBoss.


Security domains


Adding users

To add a user with a role, let’s use the add-user.bat script,

choosing ApplicationRealm

By doing so, the new user will be added to the properties

files referenced by the security-domain

IMPORTANT:

The EJB class has to be annotated with the security

domain: @org.jboss.ejb3.annotation.SecurityDomain("other")


A secured EJB


Security – the web tier

• In order to authenticate the current user with the provider

configured in the security-domain, we also have to

configure the web part

1. Add a jboss-web.xml file (in the same directory as web.xml) with

the following content

so to make the web-app aware of the security-domain


Security – the web.xml

2. Add to web.xml these elements to configure authenticated access

to specified resources:


Authentication methods

• Setting auth-method as BASIC provides just a basic HTTP authentication, with a pop-up asking for username and password

• The auth-method can also be a FORM and in such case we need to specify both 1. Login page

2. Error page

• The form will have action = j_security_check and parameters names will have to be j_username e j_password mandatorily

• The following slides refer to a situation in which we have a login folder in WebContent, containing both the login and the error page. Note: the /login/* path has been commented out.


The FORM authentication method


The login page


References

• JBoss official website

http://www.jboss.org/developer/tutorials.html


Technology

JBoss AS 7 - development basics