Download Your first application using a framework

I04
Introduction to Java
Development with IDS
Jean Georges Perrin
IIUG
Tuesday, October 3rd 2006 • 09:00 – 10:00.
Platform: IDS, Java
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
2
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
3
Who am I?
• My Unix box usually answers…
4
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
5
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
6
And you…
•
•
•
•
Who knows 4GL?
Who knows Java?
Who thinks Java is difficult?
Who knows .net?
7
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
8
Architecture
Application
JDBC Driver
9
Data
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
10
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 (v3.2.0)
• Where: www.eclipse.org
11
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
12
fglpc
Your very first cup of Java
fglgo
• Hello, world… in Java
• Use of “javac”
• Use of “java”
Source code is self organizing in
packages
• Code snippet:
main {…} is MAIN … END MAIN
Modules are organized in classes
package org.iiug.test;
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, world...");
}
}
“Hello, world…” is always the
same, in any language…
13
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
14
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
15
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
16
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
17
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
18
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
19
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") + ")");
}
20
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
21
Declaring objects to use
Connection = DATABASE
• Code snippet:
// Define my local variables
Connection myConnection;
Statement myStatement;
ResultSet myResultSet;
Statement = STATEMENT
• 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.
ResultSet = ARRAY OF RECORD
/ CURSOR
22
Loading the driver
• Code snippet:
// 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
• Drivers are uniquely named, for IBM Informix:
com.informix.jdbc.IfxDriver
23
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
24
Your first application using Eclipse
•
•
•
•
Create a project
Add the library
Create the class
Run it
25
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
26
Your first application using a
framework
• Goals of a framework
• Ease of use
• Small learning curve
• Database connectivity
• Business logic
27
BlueGazelle
• Open Source framework
• Soon to be downloadable from
http://www.greenivory.com
28
BlueGazelle Source Code
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
29
Conclusion
• Java offers a standard way of accessing data.
• Java is working in a distributed environment.
• Frameworks simplify the developers’ life.
30
And now…
• Go to my other presentation:
“Introduction to PHP development with IDS”
• (Give me good marks so I can be selected as best
speaker of the conference and beat Darryl, Lester
and Art - previous speakers).
31
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
32
I04
Introduction to Java Development with IDS
Jean Georges Perrin
IIUG
[email protected]
[email protected]
33