4-tier model client tier web tier business tier eis tier

4-Tier Model

Client TierWeb Tier

Business Tier

EIS Tier

Run 4-Tier KWIC Project on J2EE Platform

• Preparation• Packaging

– Creating the J2EE Application (.ear)

– Creating the Enterprise Bean (.jar)

– Creating the Web Client (.war)

• Deploying• Running

Preparation

• Set Environment Variables

– JAVA_HOME

= root directory of J2SE SDK installation

– J2EE_HOME = root directory of J2EE SDK installation

– PATH= %PATH%;%JAVA_HOME%\bin;%J2EE_HOME%\bin

– CLASSPATH= %CLASSPATH%;%J2EE_HOME%\lib\j2ee.jar

Preparation

• Start Cloudscape database server. – C:\> cloudscape –start

• Start J2EE server – C:\> j2ee –verbose

• Start deploytool– C:\> deploytool

• Build the database table– C:\> cloudscape –isql

WebAddressAccount

urlName (PK)

urlDescription

Packaging

• Create an Enterprise Archive (EAR) file – ProjectApp.ear

• Add Java Archive (JAR) files and Web Archive (WAR) files to the EAR– WebAddressAccountJAR: contains the enterprise bean

files and related files

– ProjectWAR: contains the Web Component files and related files

An enterprise bean is a server-side component that contains the business logic of an application

• Writes and compiles the source code• Packages the bean’s classes into EJB JAR file

– Remote Interface– Home Interface– Enterprise Bean Class

Creating Enterprise Bean

RemoteClient

RemoteInterface

HomeInterface

EJB

Remote Interface

• WebAddressAccount.java

– defines the business methods that a client may call. The business methods are implemented in the enterprise bean code

public interface WebAddressAccount extends EJBObject {

public String getUrlName();

public String getUrlDescript();

}

Home Interface

• WebAddressAccountHome.java

– defines the methods that allow a client to create, find, or remove an enterprise bean

public interface WebAddressAccountHome extends EJBHome {

public WebAddressAccount create(String urlName, String urlDescript);

public WebAddressAccount findByPrimaryKey(String urlName) ;

}

Enterprise Bean Class

• WebAddressAccountBean.java

– implements the business methods

public class WebAddressAccountBean implements EntityBean {

public String getUrlName() { return urlName; }

public String getUrlDescript() { return urlDescript; }

public String ejbCreate( String urlName, String urlDescript) {

insertRow( urlName, urlDescript);

}

public String ejbFindByPrimaryKey(String primaryKey) {

result = selectByPrimaryKey(primaryKey);

}

/*********************** Database Routines *************************/ private void makeConnection() {

InitialContext ic = new InitialContext(); DataSource ds = (DataSource)

ic.lookup(“java:comp/env/jdbc/WebAddressAccountDB”); con = ds.getConnection(); }

private void insertRow ( String urlName, String urlDescript) {

PreparedStatement prepStmt = con.prepareStatement("insert into webAddressaccount values

( ? , ? )"); prepStmt.setString(1, urlName); prepStmt.setString(2, urlDescript); prepStmt.executeUpdate(); prepStmt.close();

}}

Creating Web Component

When web client such as browser communicates with J2EE application, it dose so through server-side objects called Web components

• Writes and compiles the source code• Bundles the .class, .jsp, .html files into WAR file

Source Codes

URLListener.java

URLEventObject.javaFindHandler.jsp

Find.jsp

KeyWordSearch.javaAlphabetizer.jsp

Alphabetizer.javaCShiftLines.jspMenuFrame.html

CShiftLines.javaSaveHandler.jspWelcome.html

DetailURL.javaSave.jspindex.html

JavaBeanJSPHTML

SearchHistory.java

WebClient

save.jsp CShiftLines.jsp

saveHandle.jsp

Alphabetizer.jsp find.jsp

findHandle.jsp

WebAddressAccountBean webaddressaccount

DetailURLCShiftLine

Alphabetizer

KeyWordSearch

SaveHistory

Web Container

EJB Container

JSP Syntax

Include <%@ page import="CShiftLines, DetailURL" %>

Declaration <%! private DetailURL url ; %>

Scriptlet <% Code fragment %>

Expression <%=url_name%>

– Locating the home interfaceObject objRef =

ic.lookup("java:comp/env/ejb/TheWebAddressAccount");

WebAddressAccountHome home = PortableRemoteObject.narrow(objRef,

WebAddressAccountHome.class);

– Creating an Enterprise Bean InstanceWebAddressAccount joe = home.create( url_name, url_descript);

– Invoking business methodsWebAddressAccount findone

= home.findByPrimaryKey(oneURLName);

findone.getUrlDescript();

JNDI Names and Resource References

• JNDI: Java Naming and Directory Interface• J2EE components locate objects by invoking the

JNDI lookup method

• The JNDI name of a resource and the name of the resource reference are not the same

• This approach to naming requires that you map the two names before deployment

Specifying a Resource Reference

The WebAddressAccountBean code refers to the database as follows: private String dbName = "java:comp/env/jdbc/WebAddressAccountDB";

Mapping Resource Referenceto JNDI Name

Specifying a Resource Reference

In lookup methods, the Web client refers to the home of an enterprise bean: Object objRef = ic.lookup("java:comp/env/ejb/TheWebAddressAccount ");

Mapping Resource Referenceto JNDI Name

Deploying

• Select Tools -> Deploy• In the JNDI Names dialog box, verify the names • In the WAR Context Root dialog box, enter kwicProject in the Context Root field, which will be part of the URL

Running

http://localhost:8000/kwicProject Change the default port number (8000) by editing the

Config/web.properties file

Modifying the J2EE Application

• Change the source code • Recompile it• Redeploy the application

– Select Tools -> Update Files

– Select Tools -> Deploy

Or

– Select Tools -> Update And Redeploy