Struts lesson 2: JSP-files packed into an EAR (Enterprise-ARchive)

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Last revision of this document:
2005-07-01

This document describes the creation of a JSP-file (JSP – Java Server Page) with integrated functionality to display time and TCP/IP_address of the caller.
This lesson is using the Struts-framework (see JS_Struts00) under Eclipse, packing the JSP-files into a WAR, defining parameters in the 'application.xml'-file, packing the files into one EAR (Enterprise Archive) file and deploying the EAR-file to JBoss-Java-Application-Server.

In the 'application.xml'-file is another 'context-root' defined. This allows to call the site under another name than the name of the WAR- or EAR-file.

`Credits:`

I derived that lesson from a lot of sources found in the internet. I thank the numerous authors for their contribution.

Prerequisites:

JS_Struts01 – HTML in a WAR completed – and its prerequisites too.
Basic knowledge of Java programming language; particular the usage of libraries.

Recommended:
JS_Base01 - HelloWorld completed – if you are a newbie with Eclipse.

`Preparation:`

Create a new project (named JS_Struts02) by copying the Struts-framework (JS_Struts00):

Right click onto the project JS_Struts00 and select >Copy.
Right click onto any project or the white space on the 'Package Explorer' window and select >Paste.

Replace the 'Project name' from the default value (Copy of JS_Struts00) to the new name (JS_Struts02) and press the [ OK ] button thereafter.

In the 'Package Explorer' window you should see a new project with the name 'JS_Struts02' with the following structure. (You can expand/collapse the structure by clicking onto the triangles left of the folders.)

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`Writing the JSP-code:`

Write the start-page (index.jsp) – which will be the only page in this lesson.

Right click onto the folder 'web-pages' and select >New>File.
Enter the 'File name' (index.jsp) and press the [ Finish ] button thereafter.

Aim of this lesson is mainly to write a JSP-file an create an EAR; so the JSP- and HTML-code is kept pretty simple. There is one 'index.jsp' file which displays the current date/time and the TCP/IP-address of the caller.

Eclipse has already opened the file for edit and the code can be entered. <%@ page language=“java“ %> <%@ page import=“java.util.*, java.text.*“ %> <html> <head> <title>JavaScout Struts-Tutorial lesson 02</title> </head> <body> <h1>Welcome at lesson 2 of the JavaScout Struts-Tutorial !</h1> This is the index.jsp page. The current time is: <% Date now = new Date(); out.println(DateFormat.getTimeInstance().format(now)); %> Thank you for calling this Java-Server-Page ! This page was called from the machine with TCP/IP-address <%out.println(request.getRemoteAddr());%> </body> </html> The entered text can be saved by clicking the right mouse-button and selecting Save from the context menu.

A short explanation of the newly introduced elements in the code. These elements are interpreted by the Java-Application-Server as soon as the web-page is called.

<%@ page language=“java“ %> Directive to use the Java programming language for all code embraced by <% and %>.
<%@ page import=“java.util.*, java.text.*“ %> Import the listed libraries; they are used by Java-code later.
<% Date now = new Date(); out.println(DateFormat.getTimeInstance().format(now)); %> Define a variable named 'now' of type 'Date' and get the actual date/time. Convert the time part into a text-string and insert (print) it at the actual position within the HTML-code.
<%out.println(request.getRemoteAddr());%> Get the TCP/IP-address of the caller for this web-site and insert (print) it at the actual position within the HTML-code.

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`Making the packaging configuration and pack the HTML-files into a WAR (Web-ARchive):`

This is an intermediate step in this lesson as the final aim is an EAR (Enterprise Archive) file. The WAR-file can be deployed to the Java-Application-Server for an intermediate test.

Define, which files are packed into the WAR – in this lesson it is only one.

Right click onto the project 'JS_Struts02' and select >Properties.
In the left window select 'Packaging Configurations'. Click the [ Add... ]-button.
Enter the name of the destination-file (JS_Struts02.war) into the field 'Name' and click the [ OK ]-button.
Right click onto the displayed file (JS_Struts02.war) and select >Add Folder... .
On the 'Folder Selection'-window click the [Project Folder...]-button. On the 'Select a Folder'-window select the folder 'web-pages' of the project 'JS_Struts02' and click the [ OK ]-button. The 'Select a Folder'-window closes and the folder-name is transfered to the input field 'Folder' of the 'Folder Selection'-window. To finish, click the [ OK ]-button on the 'Folder-Selection'-window.

Note: The purpose of the other input-fields on the 'Folder Selection'-window is explained in further lessons. The outcome of the selection is, that the (to be generated) WAR-file contains all files of the folder 'web-pages' with the structure of the sub-folders kept intact.
To verify, that the files of the selected folder and its sub-folders is in the Packaging Configuration, the 'Properties'-window looks like follows. To generate a file with the data to be packaged, click the [ OK ]-button.
To start the packaging process, right-click onto the project (JS_Struts02) and select >Run Packaging .
The build-process can be watched in the 'console'-window.

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`Intermediate Run / Test:`

Before the lesson continues with packaging into an EAR-file, it is advisible to verify, if the WAR-file with the 'index.jsp'-file is error free.
The simpliest check is, to deploy the WAR-file to the Java-Application-Server.

For the conceptional background of deployment to a Java-Application-Server and the assumptions of the directories with the Eclipse-workspace and and the Java-Application-Server-deployment, please see Run / Test in JS_Struts01 – HTML in a WAR .

To deploy the WAR-file, open a 'Terminal'-window and enter the following command: cp /home/kurti-o/workspace/JS_Struts02/JS_Struts02.war /opt/jboss/server/default/deploy . If the JBoss-Application-Server was started in a 'Terminal'-window (which is recommended for this lesson) and messages are displayed, JBoss displays a message similar to this: .

The result of lesson 1 can be seen on a web-browser. Enter the following URL: http://192.168.0.62:8080/JS_Struts02 (In the example, the JBoss-Application-Server is running on a machine with the TCP/IP-address '192.168.0.62'.) and you can see the result: .

Note: There is also a functionality in Eclipse to define the Java-Application-Server and deploy and undeploy with an Eclipse-function. I was not pretty happy with that feature. My JBoss-Application-Server is running on another machine. When this machine is not running during the start of Eclipse, the Eclipse-function gets confused, reports that a changed WAR-file is deployed - but the old file is not overwritten. So I prefer to stay on the more secure side and copy the files using the 'Terminal'-window. top.

`Defining of the 'application.xml'-file as a prerequisite for an EAR (Enterprise-ARchive):`

As the project should be registered under another name (strutslesson02) than the name of the WAR-file (JS_Struts02.war), it is necessary to find out which parameter-file is responsible for that. As the concept of the WAR does not know a different registration-name, the WAR-file (and the parameter-file(s)) is packed into an EAR (Enterprise-ARchive) file. In one of the following lessons is also shown, that the EAR can contain other parameter-files, e.g. references to a database.

Define the (different) registration name (strutslesson02) under which the web-site will be registered in the Java-Application-Server. This parameter is set.

Expand the project-structure to see the content of the folder 'META-INF'. Right click onto the folder 'META-INF' and select >New>File.
Enter the 'File name' (application.xml) and click the [ Finish ]-button.

Eclipse has already opened the file for edit and the parameters can be entered. <?xml version=“1.0“ encoding=“UTF-8“?> <!DOCTYPE application PUBLIC “-//Sun Microsystems, Inc.//DTD J2EE Application 1.3//EN“ “http://java.sun.com/dtd/application_1_3.dtd“> <application> <display-name>JavaScout Struts-Tutorial, lesson 02</display-name> <module> <web> <web-uri>JS_Struts02.war</web-uri> <context-root>strutslesson02</context-root > </web> </module> </application> The entered text can be saved by clicking the right mouse-button and selecting Save from the context menu.

A short explanation of the elements in the parameters. These elements are interpreted by the Java-Application-Server as soon as the web-page is called.

<?xml version=“1.0“ encoding=“UTF-8“?> <!DOCTYPE application PUBLIC “-//Sun Microsystems, Inc.//DTD J2EE Application 1.3//EN “http://java.sun.com/dtd/application_1_3.dtd“> Directive, which character-set is used and according to which version of the J2EE-specification the parameters have to be interpreted.
<display-name>JavaScout Struts-Tutorial, lesson 02</display-name> Full name of the element, this is displayed in the list of deployed elements in the Java-Application-Server.
<web-uri>JS_Struts02.war</web-uri> File containing the HTML-files building the web-site. Full name of the element, this is displayed in the list of deployed elements in the Java-Application-Server.
<context-root>strutslesson02</context-root > Short-name, under which the EAR is registered within the Java-Application-Server and under which it can be called from a web-browser.

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`Making the packaging configuration and pack the files into an EAR (Enterprise-ARchive):`

This is the final packaging-configuration.

Pack the WAR-file and the 'application.xml' parameter-file into the EAR-file..

Right click onto the project 'JS_Struts02' and select >Properties.
In the left window select 'Packaging Configurations'. Click the [ Add... ]-button.
Enter the name of the destination-file (JS_Struts02.ear) into the field 'Name' and click the [ OK ]-button.
Right click onto the displayed file (JS_Struts02.war) and select >Add File... .
On the 'File Selection'-window click the [Project File...]-button. On the 'Select a File'-window select the file'JS_Struts02.war' of the project 'JS_Struts02' and click the [ OK ]-button. The 'Select a File'-window closes and the file-name is transfered to the input field 'File' of the 'File Selection'-window. To finish, click the [ OK ]-button on the 'File-Selection'-window.
Do the 'Add File...' part again.
On the 'File Selection'-window click the [Project File...]-button again. On the 'Select a File'-window select the file'application.xml' of the folder 'META-INF' and click the [ OK ]-button.
The 'Select a File'-window closes and the file-name is transfered to the input field 'File' of the 'File Selection'-window. On the field 'Prefix' enter the value 'META-INF' To finish, click the [ OK ]-button on the 'File-Selection'-window. The 'Prefix' ('META-INF') directs the following builder to put the file 'application.xml' into a folder 'META-INF' within the packed file 'JS_Struts02.ear': When the EAR-file is deployed, the Java-Application-Server looks unter thze 'META-INF' folder for deployment directives.
To verify, that the files of the selected folder and its sub-folders is in the Packaging Configuration, the 'Properties'-window looks like follows. To generate a file with the data to be packaged, click the [ OK ]-button.
To start the packaging process, right-click onto the project (JS_Struts02) and select >Run Packaging .
The build-process can be watched in the 'console'-window.

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`Run / Test:`

This is the final verification if the generated 'JS_Struts02.ear' file (with an Enterprise ARchive structure) is running error-free within a Java-Application-Server.

To deploy the EAR-file, open a 'Terminal'-window and enter the following command: cp /home/kurti-o/workspace/JS_Struts02/JS_Struts02.ear /opt/jboss/server/default/deploy . If the JBoss-Application-Server was started in a 'Terminal'-window (which is recommended for this lesson) and messages are displayed, JBoss displays a message similar to this: .

The result of lesson 2 can be seen on a web-browser. Enter the following URL: http://192.168.0.62:8080/strutslesson02 (In the example, the JBoss-Application-Server is running on a machine with the TCP/IP-address '192.168.0.62'.) and you can see: .

Struts lesson 2: JSP-files packed into an EAR (Enterprise-ARchive)

Credits:

Prerequisites:

Preparation:

Writing the JSP-code:

Making the packaging configuration and pack the HTML-files into a WAR (Web-ARchive):

top.

Intermediate Run / Test:

Defining of the 'application.xml'-file as a prerequisite for an EAR (Enterprise-ARchive):

Making the packaging configuration and pack the files into an EAR (Enterprise-ARchive):

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Run / Test:

Related Documents:

`Credits:`

`Preparation:`

`Writing the JSP-code:`

`Making the packaging configuration and pack the HTML-files into a WAR (Web-ARchive):`

`top.`

`Intermediate Run / Test:`

`Defining of the 'application.xml'-file as a prerequisite for an EAR (Enterprise-ARchive):`

`Making the packaging configuration and pack the files into an EAR (Enterprise-ARchive):`

`top.`

`Run / Test:`

`Related Documents:`