j2ee introduction

J2EEJ2EE

To Understand the relevance and implication of J2EE, in the present day E-enabled business environment

J2EE J2EE

ObjectivesObjectives

To understand and appreciate the distinguishing characteristics of J2EE

To understand the J2EE Application Programming Model

To understand the Components that makeup J2EE

To develop a simple J2EE application using various server-side Java Components To understand Web Application Servers as implementations of J2EE

Part-I Introducing J2EE Current problems with enterprise-wide networked application environments Future needs What is J2EE? How J2EE meets the challenge? A taste of J2EE

Part-II Components of J2EE J2EE application programming model Components & component APIs – an in-depth look Interactions between the components A component-based development approach

Part-III Application Development with J2EE Developing Servlets and JSPs Developing Enterprise JavaBeans (EJBs) Interactions between the components Architecting a simple J2EE application

Part-IV J2EE Web Application Servers Implementing J2EE : Web application servers Features of Web application servers J2EE certification for Web application servers Future of J2EE

J2EEJ2EE

OrganisationOrganisation

Basic understanding of Java language Basic OOP concepts Basic understanding of E-Commerce applications

J2EEJ2EE

Assumed knowledgeAssumed knowledge

Introducing Introducing J2EEJ2EE

Current problems with enterprise application environments Future needs What is J2EE ? How J2EE meets the challenge A taste of J2EE

Part-IPart-I OrganizationOrganization

Introducing J2EEIntroducing J2EE

Current problems with Current problems with enterprise application environments enterprise application environments


Unix / Solaris / Windows NT/Windows XP/ 2000 / Windows 95, 98 etc.

Presence of multiple hardware / operating system Presence of multiple hardware / operating system combinationcombinations

Introducing J2EEIntroducing J2EE Current problems with enterprise application environmentsCurrent problems with enterprise application environments


Weak application programming models

Lack of serious OOP design and application architectureLack of serious OOP design and application architecture

PROCEDURALPROGRAMS

OBJECTS OBJECTS

OBJECTS OBJECTS

OBJECTS OBJECTS


Less than 30% of the code is reused, currently

Minimal or no reuse of codeMinimal or no reuse of code


Lack of portability. Entire system becomes a huge and complex behemoth System more and more difficult to handle – as the business becomes

more and more complex.

Rigidity and InflexibilityRigidity and Inflexibility


Exchange of data across departments : a nightmare Exchange of data outside the enterprise : ruled out

DATA

Serious problems in integrated data flowSerious problems in integrated data flow

Dept 1

Dept 2

Dept 3

Dept 4


Back-end systems integration Back-end systems integration

Highly heterogeneous environment - Legacy systems, Relational Databases, ERP Implementations etc.

Need to cope up with scattered enterprise information systems

Future NeedsFuture Needs


Introducing J2EEIntroducing J2EE Future needsFuture needs

Internationalization and GlobalizationInternationalization and Globalization

Business applications must meet the challenges imposed by distributed development environment

Developers - and even applications may be distributed !


Unique challenges of e-BusinessUnique challenges of e-Business

Business must embrace the Internet and e-Commerce – not only for growth, but for very survival !

Need to face a whole new set of problems like Security , Scalability, Load-balancing , Fail-over , Availability


Challenges of E-Commerce driven businessChallenges of E-Commerce driven business

Businesses should rapidly adopt themselves to B2B transactions Otherwise, they will be left behind !


Businesses need Rapid Application DevelopmentBusinesses need Rapid Application Development

Need to respond quickly and effectively in the dynamic market environments….

Competitor is just a click away!


Need to develop quality solutions at competitive prices, in no time!

Businesses cannot spend heavily on Information Technology Businesses cannot spend heavily on Information Technology in the futurein the future


Can it ever be accomplished ?

Challenges in re-architecting systems for multi-tier Challenges in re-architecting systems for multi-tier application developmentapplication development

TIER 1 TIER 2 TIER 3


Unified development efforts and co-ordination

Need to have a standard environment and a common Need to have a standard environment and a common platformplatform


Nobody can neglect

Relevant even to small and medium scale enterprises Relevant even to small and medium scale enterprises because of B2B transactionsbecause of B2B transactions

What is J2EE?What is J2EE?


An enterprise-level platform for developing portable, secure, scalable, distributed, multi-tier business applications with Java.

Java 2 Platform, Enterprise EditionJava 2 Platform, Enterprise Edition

Introducing J2EEIntroducing J2EE What is J2EE?What is J2EE?


. . . with a rich set of server-side Java APIs

It is an application development platformIt is an application development platform

CLIENTSCLIENTS E I SE I SWEB CONTAINERWEB CONTAINER

EJB CONTAINEREJB CONTAINER

ENTERPRISE SERVICESENTERPRISE SERVICES

Model 1 architecture

JSP Architecture

Model 2 architecture


. . .describing how enterprise applications need to be built / structured

It is an application programming model It is an application programming model

CLIENTSCLIENTSTIERTIER

External Clients from

INTERNET (Browsers ,

WAP etc.) Applets

Internal Clients from INTRANET

(Browsers , Desk top

Applications etc.)

Applets, Javabeans

BACK END BACK END TIERTIER

J2EE WEB APPLICATION SERVER TIERJ2EE WEB APPLICATION SERVER TIER

PRESENTATION PRESENTATION LOGIC LOGIC

(Web Components)

BUSINESS LOGICBUSINESS LOGIC(EJB Container )

ENTERPRISE SERVICES

HTML

JDBC

XML

SERVLETS

JSP

WML

EJB EJB

EJB EJB

EJBEJB

JNDI JMS JTS

RMI - IIOP

EnterpriseInformation

Systems

(Databases,ERP,

Legacy Systems)


. . .for developing middleware web application services

It is a standard middleware architectureIt is a standard middleware architecture

How J2EE meets the challengeHow J2EE meets the challenge


Java is write once and run anywhere! The JVM is available for all platforms and OS Standardised environment for development & deployment Codes can be easily ported across multiple platforms

Hardware / OS IndependentHardware / OS Independent

Introducing J2EEIntroducing J2EE How J2EE meets the challengeHow J2EE meets the challenge

Java is a strictly Object-Oriented Programming language

Adherence to OOPAdherence to OOP


CLASS

CLASS

CLASS

CLASS

CLASS

CLASS


Entire application development as bits and pieces of independent components

Self-contained modules and logic – ‘assembled’ business applications

Component-based development for code re-useComponent-based development for code re-use


Clear demarcation of various tiers across the application-independent development environment

Multi-tier application developmentMulti-tier application development





(Web Components)




Developers can work anywhere! Application components can be spread across the globe!

Distributed development & deployment made easy Distributed development & deployment made easy


Flexibility in developing and assembling solutions Portability of application components across J2EE platforms

Flexible and portable solutionsFlexible and portable solutions

Automatic load-balancing / scaling / fail-over

Satisfying the essential requirements of E-Commerce web Satisfying the essential requirements of E-Commerce web applications applications



Standardisation efforts by means of Connector architecture Support for IDL / CORBA

Back-end systems integration Back-end systems integration

A taste of J2EEA taste of J2EE


Introducing J2EEIntroducing J2EE A taste of J2EEA taste of J2EE

Multi-tier thin client architecture MVC model architecture Client tier Presentation tier Business logic tier Enterprise Platform Services tier Back-end tier: Enterprise Information Systems Developing middleware Web Application Services

J2EE as an application programming model J2EE as an application programming model

CLIENTSPRESENTATION /BUSINESS LOGIC

BACKEND


Java Servlets Java Server Pages (JSP) Enterprise JavaBeans (EJBs) Java Database Connectivity (JDBC) Java Messaging Services (JMS) Java Naming and Directory Interface (JNDI) Java Transaction Services (JTS) JavaMail XML

J2EE – as a combination of various server-side technologies J2EE – as a combination of various server-side technologies

SERVLETS

JSP

EJB

JDBC


Web application servers – implementations of J2EE reference infrastructure

J2EE – as the standard for web application serversJ2EE – as the standard for web application servers

WEB APPLICATION SERVERS

Components of J2EEComponents of J2EE

J2EE application programming model Components & component APIs – an in-depth look Interactions between the components A component- based development approach

Components of J2EE Components of J2EE

OrganizationOrganization

SERVLETS

JSP

EJB

JDBC

J2EE Application Programming J2EE Application Programming ModelModel


Components of J2EE Components of J2EE J2EE Application Programming ModelJ2EE Application Programming Model

J2EE application programming modelJ2EE application programming model

CLIENTCLIENTTIERTIER



PRESENTATION LOGIC PRESENTATION LOGIC (Web Components)



Client tier componentsClient tier components


CLIENTCLIENTTIERTIER

External Clients from INTERNET

(Browsers , WAP etc.)

Applets


(Browsers , Desk top Applications etc.)

Applets, Javabeans






Presentation logic components (or web components)Presentation logic components (or web components)





Applets



Applets, Javabeans






HTML

XML

SERVLETS

JSP

WML

Business logic componentsBusiness logic components





Applets



Applets, Javabeans






HTML

XML

SERVLETS

JSP

WML

EJB EJB

EJB EJB

EJBEJB

Enterprise Service APIs Enterprise Service APIs





Applets



Applets, Javabeans






HTML

JDBC

XML

SERVLETS

JSP

WML

EJB EJB

EJB EJB

EJBEJB

JNDI JMS JTS

RMI - IIOP

Enterprise Information Systems (Hosts) Enterprise Information Systems (Hosts)





Applets



Applets, Javabeans






HTML

JDBC

XML

SERVLETS

JSP

WML

EJB EJB

EJB EJB

EJBEJB

JNDI JMS JTS

RMI - IIOP


Systems

(Databases,ERP,

Legacy Systems)

Interactions between the Interactions between the Components Components


Components of J2EE Components of J2EE Interactions between the ComponentsInteractions between the Components

Various interactions between the J2EE componentsVarious interactions between the J2EE components




Applets



Applets, Javabeans






HTML

JDBC

XML

SERVLETS

JSP

WML

EJB EJB

EJB EJB

EJBEJB

JNDI JMS JTS

RMI - IIOP


Systems

(Databases,ERP,

Legacy Systems)

Components and Component APIs - Components and Component APIs - an in-depth lookan in-depth look


HTML

JDBC

XML

SERVLETS

JSP

WML

EJB EJB

EJB EJB

EJBEJB

JNDI JMS JTS

RMI - IIOP

Standard Java extensions to the basic web server framework. Provide additional functionality to the server / enable dynamic

content creation. Programmers can extend Servlets for their applications. Servlets reside in Servlet engines.

Components of J2EE Components of J2EE Components and Component APIs - an in-depth lookComponents and Component APIs - an in-depth look

Java ServletsJava Servlets


HTML

XML

SERVLETS

JSP

WML

HTTP Clients

(Internal & External)

Another set of server side Java APIs to enhance web server functionality Collecting data / presenting processed results to the client Java snippets can be embedded into normal HTML code Closely linked interaction with JavaBeans API


Java Server Pages (JSP)Java Server Pages (JSP)


HTML

XML

SERVLETS

JSP

WML

HTTP Clients

(Internal & External)

Scalable, distributed server-side Java components for encapsulating business logic

Each EJB serves a specific set of well-defined business tasks. EJBs reside in EJB containers, which are an integral part of vendor’s J2EE

implementation and provide crucial system-level services All EJBs should be coded to standard EJB API specifications. Types of EJBs: Stateful Session EJBs, Stateless Session EJBs, Entity EJBs etc. Different types of EJB will be introduced in the future


Enterprise JavaBeans (EJB)Enterprise JavaBeans (EJB)



SERVLETS

JSP

EJB EJB

EJB EJB

EJBEJBRMI

Standard Java API for connecting to various databases “Hides” the database from the eyes of the program


Java Database Connectivity (JDBC)Java Database Connectivity (JDBC)

Informix

Oracle

SQL Server

SERVLETS

EJB JDBC API

OtherJava

Classes

JDBCDriver/DB API

Standard Java API for distributed lookup services


Java Naming and Directory Interface (JNDI)Java Naming and Directory Interface (JNDI)

SERVLETS

JSP

RMI

JNDI API / NAMING MANAGER/SERVICE PROVIDER

INTERFACE

LDAP / File

System /DNS /

Drivers

LDAPServer

File System

DNSServer

Standard Java API for Enterprise Messaging Systems


Java Messaging Services (JMS)Java Messaging Services (JMS)

JMS APIEnterpriseMessaging

System

M MM

M MM

Transmission

Reception

Standard Java API for Distributed Transaction Services


Java Transaction API (JTA)Java Transaction API (JTA)

EJB JTA

OtherTransactional

Classes

Transaction Monitor

JDBCAPI

Standard Java API for Mail Server Services (SMTP / IMAP)


JavaMail API / JAFJavaMail API / JAF

RMI is a Java API for object-to-object communication between different java Virtual Machines (JVM) RMI over Internet Inter-Orb Protocol (RMI-IIOP) integrates CORBA-compliant distributed computing directly into Java


Java RMI / IIOP / IDLJava RMI / IIOP / IDL

A component-based development A component-based development approachapproach


EJB

EJB

EJB

EJB

EJB

Required components can be ‘plugged in’ and ‘plugged out’

Components of J2EE Components of J2EE A component-based development approach

Pluggable ArchitecturePluggable Architecture

Components that have relevance beyond the scope of the project EJBs should be generic – Servlets / JSPs can be specific Logic libraries (Packages) should be generic


Generic components vs. application specific componentsGeneric components vs. application specific components

SERVLETS

EJB EJB

EJB

JSP

GenericUtilities

Directory names and URLs Database parameters – table names, database URL etc. Application specific parameters


Identifying the right deployment parametersIdentifying the right deployment parameters

Application Development Application Development with J2EEwith J2EE

Developing Servlets & JSPs Developing Enterprise JavaBeans (EJBs) Interactions between the components Architecting a simple J2EE application

Application Development with J2EE Application Development with J2EE


Developing Servlets and JSPsDeveloping Servlets and JSPs


SERVLETS JSP

Application Development with J2EE Application Development with J2EE Developing Servlets and JSPsDeveloping Servlets and JSPs

Servlets - Core ConceptsServlets - Core Concepts

Server side Java Classes, that reside in J2EE Presentation Logic Tier Servlets are based on Request – Response models All Servlets extend javax.servlet.Servlet Interface. Most of the application Servlets extend javax.servlet.http.HttpServlet

class ServletRequest and ServletResponse objects enable interaction with

the clients Instantiate EJBs for business data processing

SERVLETS


Servlets - LifecycleServlets - Lifecycle

Servlet Engine instantiates and loads the Servlet - either during startup or first request call

Initialisation performed through init() method - only once throughout the life of Servlet

Servlet threads are created for multiple requests. All threads use same Servlet instance.

Business tasks are performed through the service() methods

In the event of a timeout or web server shutdown, Servlet’s destroy() method is called

Java Virtual Machine does the garbage collection- finalize() method is called

Does Not Exist

Servlet Instance


Servlets - A simple exampleServlets - A simple example

import javax.servlet.*;import javax.servlet.http.*;

public class SimpleServlet extends HttpServlet {public void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException{ res.setContentType("text/html"); ServletOutputStream out = res.getOutputStream();

out.println("<html>"); out.println("<head><title>Simple Servlet</title></head>"); out.println("<body>"); out.println("<h1>Hello J2EE !</h1>"); out.println("</body></html>"); }}


JSPs - Core ConceptsJSPs - Core Concepts

JSP

Server-side Java code that resides in J2EE presentation logic tier JSPs are based on Request – Response models Contain HTML code for presenting information, plus directives and

scriplets for processing. JSPs interact with Servlets and JavaBeans Internally JSPs are no different from Servlets Dynamically compiled – unlike Servlets Can instantiate EJBs – but not advised to do so.


JSP - LifecycleJSP - Lifecycle

JSP Engine dynamically complies the JSP page as a servlet class

JSP Engine instantiates and loads the class - during the first request call

Initialisation performed through jspInit() method - only once throughout the life of JSP

Threads are created for multiple requests. All threads share the same instance.

Business tasks are performed through the _jspService() methods

In the event of a timeout or web server shutdown, jspDestroy() method is called

Does Not Exist

JSP Instance


JSP - A simple exampleJSP - A simple example

<%!String a = “hai”;String b = “hai J2ee”;

%><HTML> <h1> Current Date </h1>Today’s date is : <%= new Date().toString() %><%

if (a.equalsIgnoreCase(b)){

%><font name=”ariel”>A is equal to B</font>

<%}

%></HTML>


A Simple JavaBeanA Simple JavaBean

public class Presentation {//attributesprotected String session;protected String speaker;protected int duration_hours;//constructor methodpublic Presentation () {

this.session = “J2EE Tutorial”;this.speaker = “S.Gokul”;this.duration_hours = 4;

}//Accessor Methodspublic String getSession() {…}public void setSession() {…}………

}

Developing Enterprise JavaBeansDeveloping Enterprise JavaBeans


EJB EJB

EJB EJB

EJBEJB

EJB

Application Development with J2EE Application Development with J2EE Developing Enterprise JavaBeansDeveloping Enterprise JavaBeans

EJB : Core ConceptsEJB : Core Concepts

Server side distributed, load balanced, scalable business logic components, that reside in the business logic tier

Built on the top of Java RMI specification for distributed computing EJB Container manages EJBs – pooling, distribution, creation,

activation etc. Three types of EJBs : Stateless Session, Stateful Session and Entity

EJBs Each EJB Contains at least 3 user-defined classes and a number of

Container classes. Home Interface – meant for EJB creation; Remote Interface - meant for

using business logic; Bean Class – actual implementation details. Clients can access EJBs only through interfaces. Containers manage

the implementation.


EJB : Breathing to LifeEJB : Breathing to Life

CLIENT

ejbCreate () from Home stub reference

Create EJB InstanceCreate Remote stub & Skeleton

Home stub deployed during startup

JNDI EJB CONTAINER

Home Stub obtained from JNDI

Return the remote stub reference

Invoke business methods through the remote stub reference

Process data

Return Results


EJB : Breathing to LifeEJB : Breathing to Life

EJB Containers manage the enterprise bean life cycle For each EJB in the system, a home stub is deployed into JNDI –

during the application server startup Clients download a copy of the home stub, to create an EJB instance

in the server. Upon this request, EJB container creates an EJB instance, gives it

state and associates a client context to it. It also creates a remote skeleton and a remote stub The remote stub is returned by the home skeleton Client invokes business methods, through remote stub All clients get identical home stubs, but unique remote stubs !


Stateless Session EJBsStateless Session EJBs

Provide a well-defined set of business services to the client Do not maintain state on the behalf of client and hence, do not have

attributes. Do not survive EJB Container crashes. All Stateless EJB instances are identical – and can be reused. Less resource hungry – ideal for clustered environment.

EJB


Stateful Session EJBsStateful Session EJBs

Provide business services and maintain state on behalf of client. Stores the state as attribute, for temporary usage. Do not survive EJB Container crashes. Every Stateful EJB instance is unique & tied to the client – hence, they

cannot be reused. Lifetime is determined by the client. More resource hungry – should be avoided in a clustered environment.

EJB


Entity EJBsEntity EJBs

Retrieve and store information from the database Represent persistent business data – every record in the table, is an

entity bean (single table model) They survive EJB Container crashes Multiple clients may use the same EJB - that represents the same set

of data – but they are not same Entity instances ! State of entity bean is persisted in the storage (file or database). Resource hungry - most useful for transactions.

EJB


(Web Components)


SERVLETS

JSP

EJB EJB

EJB EJB

EJBEJBRMI

Interactions between the Interactions between the ComponentsComponents


Application Development with J2EE Application Development with J2EE Interactions between the ComponentsInteractions between the Components

BROWSER SERVLET

Request

Presentation LogicPresentation Logic

JSP


Create EJB InstanceCreate Remote stub & Skeleton

RESPONSE


JNDI EJB CONTAINER

Home Stub obtained from JNDI


Invoke business methods through the remote stub reference

Process data

Return Results

Forward Response

with ResultsResponse

Business LogicBusiness Logic

The necessary EJBs / Servlets and JSPs are developed and deployed in the J2EE server

Server is started A client request hits a Servlet Servlet gathers / validates the input data, creates an EJB and forwards

the data to EJB for processing EJB processes the data by applying business rules / interacting with

the database, and responds with the processed results. Servlet gathers the response and forwards to a JSP appropriately. JSP loads the response HTML page to the client.

Application Development with J2EE Application Development with J2EE Interactions between the ComponentsInteractions between the Components

A Typical Interaction ScenarioA Typical Interaction Scenario

Architecting a simple J2EE Architecting a simple J2EE ApplicationApplication


Application Development with J2EE Application Development with J2EE Architecting a simple J2EE ApplicationArchitecting a simple J2EE Application

Application SequenceApplication Sequence

BROWSER SERVLET

Request : Collect User name and Password

Presentation LogicPresentation Logic

JSP


Create Authenticate EJB Instance

Create Remote stub & Skeleton

RESPONSE


JNDI EJB CONTAINER

Authenticate EJB Home Stub obtained from JNDI


Verify Username and Password (Business method)

Process data

Return Results (True or False)

Forward Response

with ResultsResponse

Business LogicBusiness Logic

Userdata EJB Home Stub obtained from JNDI

The Request from HTTP client hits the Servlet Username and password are collected from the Request object The Authenticate stateless session EJB is initialised Username and password are passed to this EJB for verification This EJB returns True if the user details are correct If the details are not correct, inform the user accordingly If the details are correct, create / findbyPrimaryKey - an Entity EJB

called Userdata with Username and Password as keys


Application SequenceApplication Sequence

Table DetailsTable Details


NAME

LOGINNAME

PASSWORD

EMAIL

AGE

SERVICE

Servlet CodeServlet Code


package portal;import java.io.*;import java.sql.*;import java.util.*;

import javax.servlet.*;import javax.servlet.http.*;import java.net.URL;

import javax.ejb.*;import javax.naming.*;

public class login extends HttpServlet {static String url = "http://17.252.11.139:7001";static String connection_pool = "";static String user = “guest”;public void init()throws ServletException{ String connection_pool = "oraclepool";}

Servlet Code (Cont..)Servlet Code (Cont..)


public void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException{

//ACCPET THE FORM VARIABLES AS STRINGS FROM HTMLString login = req.getParameter("login");if (login == null) login = "";else login = login.trim();String password = req.getParameter("password");if (password == null) password = "";else password = password.trim();//INITIALISING RESPONSE WRITERres.setContentType("text/html");PrintWriter out = res.getWriter();

boolean result = false;



//THIS BLOCK IS INSIDE THE SERVICE METHODtry{ Context ctx = getInitialContext(); AuthenticateHome home = (AuthenticateHome) ctx.lookup("Authenticate"); Authenticate session_ejb = home.create();

result = session_ejb.check_authentication(login, password);

//System.out.println(”session ejb = " + session_ejb.toString());

session_ejb.remove();}catch (Exception e){ e.printStackTrace();}



//SEPARATE METHOD - NOT INSIDE THE SERVICE BLOCKpublic static Context getInitialContext() throws NamingException{Properties p = new Properties(); p.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory"); p.put(Context.PROVIDER_URL, url);

if (user != null) { p.put(Context.SECURITY_PRINCIPAL, user); if (password == null) password = ""; p.put(Context.SECURITY_CREDENTIALS, password); } return new InitialContext(p);}



//THIS BLOCK IS INSIDE THE SERVICE METHODif (result){ try{ Context ctx = getInitialContext(); UserdataHome home = (UserdataHome) ctx.lookup(”Userdata"); Userdata entity_ejb = home.create(login, password);

//...

}catch (Exception e){ e.printStackTrace();}

Authenticate Stateless Session EJBAuthenticate Stateless Session EJB


//HOME INTERFACE CODE (AuthenticateHome.java)package portal;

import javax.ejb.*;import java.rmi.RemoteException;

public interface AuthenticateHome extends EJBHome{

//CREATE METHOD TO BE IMPLEMENTED IN BEAN CODEpublic Authenticate create()throws CreateException, RemoteException;

}

Authenticate Stateless Session EJB (Cont..)Authenticate Stateless Session EJB (Cont..)


//REMOTE INTERFACE CODE (Authenticate.java)package portal;

import javax.ejb.*;import java.rmi.RemoteException;

public interface Authenticate extends EJBObject{

//BUSINESS METHODS TO BE IMPLEMENTED IN BEAN CODEpublic boolean check_authentication(String username, String password)throws RemoteException;

}



//BEAN CODE (AuthenticateEJB.java)package portal;import javax.ejb.*;import java.util.*;import javax.naming.*;import java.io.*;import java.sql.*;

public class AuthenticateEJB implements javax.ejb.SessionBean{private SessionContext ctx;public AuthenticateEJB(){}// SessionBean interface implementationpublic void ejbActivate(){}public void ejbPassivate(){}public void ejbRemove(){}



public void setSessionContext(SessionContext ctx){this.ctx = ctx;

}// create methodspublic void ejbCreate(){}// business methodspublic boolean check_authentication(String username, String password){ boolean result = false; username = username.toUpperCase(); password = password.toUpperCase(); Connection con = null; Statement stmt = null;



//check_authentication method Blocktry{ Class.forName("weblogic.jdbc.pool.Driver").newInstance();con = DriverManager.getConnection("jdbc:weblogic:pool:oraclepool", null); DatabaseMetaData dma = con.getMetaData ();System.out.println("\nConnected to " + dma.getURL());System.out.println("\nDriver " + dma.getDriverName());stmt = con.createStatement();String querry = "SELECT * FROM USERDATA WHERE UPPER(LOGINNAME) = '" + username + "' AND UPPER(PASSWORD) = '" + password +"'";

ResultSet rs =stmt.executeQuery(querry);

//WHEN THERE IS ATLEAST ONE RECORD RETRIEVED, USER IS VALIDwhile(rs.next()){

result = true;}

}catch (SQLException exception){

result = false;}

Userdata Entity EJBUserdata Entity EJB


//HOME INTERFACE CODE (UserdataHome.java)package portal;import javax.ejb.EJBHome;import javax.ejb.FinderException;import java.rmi.RemoteException;import javax.ejb.CreateException;public interface UserdataHome extends EJBHome{

public Userdata create(String loginname, String password)throws CreateException, RemoteException;

public Userdata findByPrimaryKey(UserdataPK key)throws FinderException, RemoteException;

public Userdata findByLoginName(String loginname)throws FinderException, RemoteException;

}

Userdata Entity EJB (Cont..)Userdata Entity EJB (Cont..)


REMOTE INTERFACE CODE (Userdata.java)package portal;import javax.ejb.EJBObject;import java.rmi.RemoteException;public interface Userdata extends EJBObject{

public void setService(String service)throws RemoteException; public String getService()

throws RemoteException; public String getUserEmail()

throws RemoteException; public String getUserName()

throws RemoteException; }



//PRIMARY KEY CLASS (UserdataPK.java)package portal;import java.io.Serializable;public class UserdataPK implements Serializable{

public String loginname;

public boolean equals(Object that) {// SBgen: Compare membersreturn(this == that);// SBgen: End compare

} }



//BEAN CODE (UserdataEJB.java)package portal;import javax.ejb.EntityBean;import javax.ejb.EntityContext;import javax.ejb.CreateException;import javax.naming.Context;import javax.naming.InitialContext;import javax.naming.NamingException;

public class UserdataEJB implements EntityBean{private EntityContext context;public String loginname;/** USERDATA.LOGINNAME */public String password;/** USERDATA.PASSWORD */public String name;/** USERDATA.NAME */public String email;/** USERDATA.EMAIL */public int age;/** USERDATA.AGE */public String service;/** USERDATA.SERVICE */



//BEAN CODE (UserdataEJB.java)public void setEntityContext(EntityContext ec){

context = ec;} public void unsetEntityContext(){

this.context = null;}

public void ejbActivate(){} public void ejbPassivate(){}

public void ejbLoad(){}

public void ejbStore(){}



//BEAN CODE (UserdataEJB.java)public UserdataPK ejbCreate(String loginname) {

this.loginname = loginname;return null;

} public void ejbPostCreate(String loginname) {} public void ejbRemove() {}

public UserdataPK ejbCreate(String loginname, String password)throws CreateException {

this.password = password;return ejbCreate(loginname);

}

public void ejbPostCreate(String loginname, String password) {

}



//BEAN CODE (UserdataEJB.java)public void setService(String service) { this.service = service;} public String getService() {

return this.service;} public String getUserEmail() {

return this.email;} public String getUserName() {

return this.name;}

}



//BEAN CODE (UserdataEJB.java)protected String getPrimarykey() {java.lang.String prop = null;try { Context initial = new InitialContext(); Context environment = (Context) initial.lookup("java:comp/env"); prop = (java.lang.String) environment.lookup("primarykey");}catch (NamingException e) {}return prop;}

Web Application ServersWeb Application Servers

Implementing J2EE : web application servers Features of web application servers J2EE Certification of application servers Future of J2EE



WEBAPPLICATION

SERVER

Implementing J2EE - Implementing J2EE -



WEBAPPLICATION

SERVER

SERVLETS

JSP

EJB

EJB

Web Application ServersWeb Application Servers Implementing J2EE - Web Application ServersImplementing J2EE - Web Application Servers

Forrester Research defines an application server as “a software

server product that supports thin clients with an integrated

suite of distributed computing capabilities. Application servers

manage client sessions, host business logic and connect to

back-end computing resources,including data,transactions,

and content.”

Web Application Servers - DefinitionWeb Application Servers - Definition

WEBAPPLICATION

SERVER

Single robust platform to develop and deploy all enterprise / web applications.

Support a variety of components – to cater to various business needs Independent of platform / OS and are capable of connecting together a

heterogeneous mix of back-end systems. Can cluster a host of server instances and treat them as a single pool

of resources – ensuring total availability Can service and monitor sensitive database transactions and allow for

increased security and control.


What can Web Application Servers do for you ?What can Web Application Servers do for you ?

WEBAPPLICATION

SERVER

Allow us to exercise more control over the overall flow of applications – caching, pooling and load balancing.

Provide efficient remote administration capabilities for the enterprise system architecture.

Capable of scaling to meet the increasing net traffic. Provide more flexibility and openness in the overall enterprise system

architecture – every end resource can be virtually ‘plugged in’ or ‘plugged out’ of a single backbone.

Increase the overall system performance – enterprise resources are routed through a single gateway.


What Web Application Servers can do for you ? (Cont..)What Web Application Servers can do for you ? (Cont..)

WEBAPPLICATION

SERVER

Vendor-specific implementations of J2EE infrastructure Features and performance distinguish the products Almost all products are J2EE-based / J2EE-compliant


Looking at J2EE Web Application ServersLooking at J2EE Web Application Servers

WEBAPPLICATION

SERVER

Integrated development environments Development and deployment of EJBs / Servlets / JSPs Example : BEA’s Webgain Studio with Visual Café, Dreamweaver,

Weblogic and Structure Builder


Developing Applications with Web Application ServersDeveloping Applications with Web Application Servers

Features of Web Application ServersFeatures of Web Application Servers


WEBAPPLICATION

SERVER

@#$%!

Wow !???

! ! ! !

Scalability and availability – capacity to meet the increasing number of client requests

Load balancing – ability to distribute requests evenly across multiple resources

Fail-over and fault tolerance – coping up with software / hardware crashes

Response time – ability to attend to the client’s request as early as possible.

Web Application ServersWeb Application Servers Features of Web Application ServersFeatures of Web Application Servers

Performance-based FeaturesPerformance-based Features

Tools and IDE support – overall application development environment Ease of use and development – overall skill set required for

development Platform Support – compatibility across multiple hardware / OS

configurations


Application Development FeaturesApplication Development Features

Open architecture – ability to accommodate multiple standards and components

Back-end integration - ability to integrate with existing EIS Web server support – major HTTP web servers supported by the product


Technical FeaturesTechnical Features

WEBAPPLICATION

SERVER

Administration and Manageability – how easy is it to maintain the overall system ?

Site monitoring / analysis and report generation Security management – user governance, requests logging, firewall /

SSL support Transaction monitoring – ability to be a database watchdog


Administrative FeaturesAdministrative Features

Availability of local technical support Pricing


Miscellaneous FeaturesMiscellaneous Features

J2EE Certification of Web J2EE Certification of Web Application ServersApplication Servers


Web Application Servers Web Application Servers J2EE Certification of Web Application ServersJ2EE Certification of Web Application Servers

Sun Microsystems’ J2EE Compliance Test and Compatibility Test suite J2EE-branded server must pass more than 6,000 tests in the

Compatibility Test suite.

How to distinguish Web Application Servers ?How to distinguish Web Application Servers ?

???

BEA’s WebLogic server Allaire’s Jrun Bluestone’s Sapphire (Total-e-server) i-Planet application server Oracle ‘s 9i application server Silverstream Ebusiness platform IBM’s Web Sphere

Web Application Servers Web Application Servers J2EE Certification of Web Application ServersJ2EE Certification of Web Application Servers

Some premier Web Application ServersSome premier Web Application Servers

Future of J2EEFuture of J2EE

Web Application Servers Web Application Servers

Web Application Servers Web Application Servers Future of J2EEFuture of J2EE

Future Development PathsFuture Development Paths

tomcat@jakarta : Is it here to stay ? New Draft : Connector Architecture / Messaging beans etc.

Web Application Servers Web Application Servers Future of J2EEFuture of J2EE

Web Application Servers of the FutureWeb Application Servers of the Future

WEBAPPLICATION

SERVER

Move towards J2EE Jini / Javaspaces and other related technologies will have an influence

Introducing J2EEIntroducing J2EE Current problems with enterprise-wide networked application environments Future needs What is J2EE? How J2EE meets the challenge? A taste of J2EE

Components of J2EEComponents of J2EE J2EE application programming model Components & component APIs – an in-depth look Interactions between the components A component-based development approach

Application Development with J2EEApplication Development with J2EE Developing Servlets and JSPs Developing Enterprise JavaBeans (EJBs) Interactions between the components Architecting a simple J2EE application

J2EE Web Application ServersJ2EE Web Application Servers Implementing J2EE : Web application servers Features of Web application servers J2EE certification for Web application servers Future of J2EE

J2EE TutorialJ2EE Tutorial

RECAPRECAP

j2ee introduction

Documents

simple j2ee application

taste of j2ee

makeup j2ee

implication of j2ee

j2ee j2eeobjectives

j2ee current problems

application development

j2ee future needs