1 Introduction to Java Development with IDS Jean Georges Perrin IIUG GreenIvory.com JGP.net Tuesday,...

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Introduction to Java Development with IDSJean Georges PerrinIIUGGreenIvory.comJGP.netTuesday, October 3rd 2006 • 09:00 – 10:00.

Platform: IDS, Java

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Agenda

Who am I? Architecture Requirements Your very first cup of Java JDBC Your first application using the Command

Prompt Your first application using Eclipse Your first application using a framework

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Agenda



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Who am I?

My Unix box usually answers…

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Who am I (outside of a Unix box)? Jean Georges Perrin Development tools (xGL, Java EE, PHP) Works with Informix products since ’97 IIUG board member

since ’02 Lives in

Strasbourg, France

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A little more…

Application developer, started with Visual Basic, in the early 90s

In the web since 1994 Move to 4GL in 1997 Goals:

Webizing all things I touched (business apps, catalogs and i-4GL…)

Find the ease of use of Visual Basic

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And you…

Who knows 4GL? Who knows Java? Who thinks Java is difficult? Who knows .net?

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Agenda



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Architecture

DataApplication JDBC Driver

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Agenda



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Requirements

#1 - IDS (from v7.x, but also works on OnLine and SE) Where: www.iiug.org,

www.informix.com #2 - Java (Java SDK v5.x)

Where: www.javasoft.com #3 - JDBC driver (IBM Informix JDBC 3.0)

Where: www.informix.com #4 - Option: Eclipse (v3.2.1)

Where: www.eclipse.org

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Agenda



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Your very first cup of Java

Hello, world… in Java Use of “javac” Use of “java”

Code snippet:

package org.iiug.test;

public class HelloWorld {

public static void main(String[] args) { System.out.println("Hello, world..."); }}

Source code is self organizing in packages

Modules are organized in classes

main {…} is MAIN … END MAIN

“Hello, world…” is always the same, in any language…

fglpc

fglgo

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Java Pros & Cons

Object Oriented (OO) development Event driven programming model User Interface (UI) & Business Logic (BL)

tightly linked Open architecture, open standards General purpose development language Industry standard Looks like “hype” to developers

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4GL Pros & Cons

Procedural development “Controlled” events UI and BL somehow separated (.per

& .4gl) Proprietary solution Business apps development language Not a standard in industry Hard to attract new developers

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Agenda



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JDBC

Types of driver (annoying theory) Standard way of talking to a database

(forget about SQL/J) Use a URL, for IBM Informix:

jdbc:informix-sqli://popeye:1526/stores_demo:informixserver=ol_popeye;user=informix;password=informix

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Agenda

Who am I? Architecture Requirements Your very first cup of Java JDBC Your first application using the

Command Prompt Your first application using Eclipse Your first application using a framework

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Your first application using the Command Prompt Understand the role of the “CLASSPATH” Full source code (copy / paste):

import java.sql.*;

public class MyFirstJDBCConnection {

public static void main(String[] args) { // Define my local variables Connection myConnection; Statement myStatement; ResultSet myResultSet; // Loading driver try { System.out.println(">> Loading the driver"); Class.forName("com.informix.jdbc.IfxDriver"); } // end try catch (ClassNotFoundException e) { System.out.println("ERROR: Failed to load IBM Informix JDBC driver."); return; } // end catch

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Your first application (2)

try { // Connection to database System.out.println(">> Connecting to the database"); myConnection = DriverManager.getConnection ("jdbc:informix-sqli://popeye:1526/stores_demo: informixserver=ol_popeye;user=informix;password=informix", "", ""); // Statement creation System.out.println(">> Creating the statement"); myStatement = myConnection.createStatement(); // Resultset creation & execution System.out.println(">> Executing the query"); myResultSet = myStatement.executeQuery ("SELECT fname, lname, customer_num FROM customer ORDER BY lname"); // Outputting the result System.out.println(">> Step 4 - Dumping data"); while (myResultSet.next()) { System.out.println ( myResultSet.getString("fname") + myResultSet.getString("lname") + " (" + myResultSet.getString("customer_num") + ")"); }

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Your first application (3)

// Cleaning System.out.println(">> Cleaning"); myResultSet.close(); myStatement.close(); myConnection.close(); } // end try catch (SQLException e) { System.out.println("ERROR: SQL exception: " + e.getMessage()); e.printStackTrace(); return; } // end catch } // end main} // end class

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Declaring objects to use

Code snippet:

The “Connection” is the real connection to the database, it is (re)created each time. Except when using “connection

pooling”. The “Statement” is the real orders or

queries to the database. The “ResultSet” contains a link to the

data.

// Define my local variables Connection myConnection; Statement myStatement; ResultSet myResultSet;

Connection = DATABASE

Statement = STATEMENT

ResultSet = ARRAY OF RECORD / CURSOR

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Loading the driver

Code snippet:

Drivers are uniquely named, for IBM Informix:

// Loading driver try { System.out.println(">> Loading the driver"); Class.forName("com.informix.jdbc.IfxDriver"); } // end try catch (ClassNotFoundException e) { System.out.println("ERROR: Failed to load IBM Informix JDBC driver."); return; } // end catch

com.informix.jdbc.IfxDriver

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Connecting to the database

Code snippet: // Connection to database System.out.println(">> Connecting to the database"); myConnection = DriverManager.getConnection ("jdbc:informix-sqli://popeye:1526/stores_demo: informixserver=ol_popeye;user=informix;password=informix", "", "");

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Statement & Execution

Code snippet: // Statement creation System.out.println(">> Creating the statement"); myStatement = myConnection.createStatement(); // Resultset creation & execution System.out.println(">> Executing the query"); myResultSet = myStatement.executeQuery ("SELECT fname, lname, customer_num FROM customer ORDER BY lname");

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Looping around

Code snippet: // Outputting the result System.out.println(">> Step 4 - Dumping data"); while (myResultSet.next()) { System.out.println ( myResultSet.getString("fname") + myResultSet.getString("lname") + " (" + myResultSet.getString("customer_num") + ")"); }

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Cleaning

Code snippet:

Not only cleaning Exception Handling!

// Cleaning System.out.println(">> Cleaning"); myResultSet.close(); myStatement.close(); myConnection.close(); } // end try catch (SQLException e) { System.out.println("ERROR: SQL exception: " + e.getMessage()); e.printStackTrace(); return; } // end catch } // end main} // end class

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Agenda



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Your first application using Eclipse Create a project Add the library Create the class Run it

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Agenda


Prompt Your first application using Eclipse Your first application using a

framework

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Your first application using a framework Goals of a framework

Ease of use Small learning curve

Database connectivity

Business logic

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BlueGazelle

Open Source framework Soon to be downloadable from

http://www.greenivory.com

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BlueGazelle Source Code

Code snippet:Database myDatabase = null;Record myRecord = null;Record myRow = null;int count = 0;int i = 0;

try { myDatabase = Databases.connect("stores_demo"); myRecord = myDatabase.createRecordFromSelect("SELECT fname, lname, customer_num FROM customer ORDER BY lname"); count = myRecord.getCount(); for (i = 0; i < count; i++) { myRow = myRecord.getRecordAt(i); System.out.println(myRow.getString("fname") + myRow.getString("lname") + " (" + myRow.getString("customer_num") + ")"); } } catch (Exception e) { System.out.println("ERROR: Exception raised: " + e.getMessage()); e.printStackTrace();} // end catch

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Conclusion

Java offers a standard way of accessing data.

Java is working in a distributed environment.

Frameworks simplify the developers’ life.

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Complexity & Features

Level of complexity / feature of languages over time

2000 20051994

Easy

Difficult

4GL

2001 2002 2003 2004 200619991998199719961995

PHPOO in PHP 4

Zend Framework?

PHP 5

J2EE

Java SE 5Eclipse

Java

Java EE 5

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And now…

Come to see me in San Jose (May 2007) Full Java Educational Seminar (you

need to stand me for 3 hours) “Introduction to EJB3 dev. with IDS

and Viper” I think I have a session or two on XML (Give me good marks so I can be

selected as best speaker of the conference and beat Darryl, Lester and Art - previous speakers and enter Hall of Fame).

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And now (seriously)…

Download Eclipse (I guess you all have IDS already)

Get a book (O’Reilly has quite a few great books)

Join the development-tools forum on IIUG web site

Get started with a few examples Come back to me

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Introduction to Java Development with IDS

Thanks for your patienceCome back to me…

[email protected]@jgp.net

1 Introduction to Java Development with IDS Jean Georges Perrin IIUG GreenIvory.com JGP.net Tuesday,...

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