Fouad's Blog

How to Use an Existing Web Service in VB.NET

admin — Fri, 12 Mar 2010 23:12:47 +0000

The aim of the following tutorial is to give you a basic information about Web Service
To execute the example in this tutorial you need visual studio 2005 or 2008 :
This is an express edition of visual studio 2008 VS2008
In this tutorial we will create a form that gets information from a web service about the euro2008 (Europe football cup) .
Firstly select a vb.net project and design a form like this:

Application Interface

In this form we will show a list of all stadiums, teams of euro2008 football cup.
Select a stadium and click the button Click, the application gets the city and capacity of the stadium selected in the stadium combobox from the webservice.
Now let’s select the reference to the web service, right click to the service references, add a service reference.

Service References

Secondly we will add the link of web service to our project: http://euro2008.dataaccess.eu/footballpoolwebservice.wso?WSDL , and click “go to” then wait until VB find to webservice, now specifiy a name for the space name of the web service then click ok, the Visual Basic generates different configuration files :

Add Service References

Now let’s write some code in the form to make the web service works correctly:

Public Class Form1
‘ ServiceReference1 is the name space that you chose
Public ws As New ServiceReference2.FootballPoolWebServiceSoapTypeClient

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

‘ define the staduim_lenght and the numbers of teams
Dim stadium_lenght, Team_count As Integer

stadium_lenght = ws.StadiumNames.Count
stadium_lenght -= 1

‘ add names of staduims from the web service to the combobox1
For i = 0 To stadium_lenght

ComboBox1.Items.Add(ws.StadiumNames.Item(i).Trim())
Next i

Team_count = ws.Teams.Count
Team_count -= 1

‘add names of teams from the web service to the combobox2

For j = 0 To Team_count

ComboBox2.Items.Add(ws.Teams.ElementAt(j).sName)
Next j
ComboBox1.SelectedIndex = 0
ComboBox2.SelectedIndex = 0
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

‘ Select then city name, staduim name, and the capacity of the stadium ‘chosen in combobox1

TextBox1.Text = ws.StadiumInfo(ComboBox1.SelectedItem.ToString()).sCityName
TextBox2.Text = ws.StadiumInfo(ComboBox1.SelectedItem.ToString()).sStadiumName
TextBox3.Text = ws.StadiumInfo(ComboBox1.SelectedItem.ToString()).iSeatsCapacity

End Sub
End Class

This is how the interface application looks at executing the program:

Executing Application

You created your first interaction with an existing web service (euro2008), if you have any comments or remarks post it in my blog or alert me by email.

How To Use XUpdate In Java With Xindice Database

admin — Sun, 07 Feb 2010 19:01:20 +0000

This Tutorial is available in PDF Book : How To Use XUpdate In Java With Xindice Database

The aim of this tutorial is to show you how to develop a simple java class that use CRUD (Create Read Update Delete ) operations with an xml file stored in a native XML Database.
firstly to begin you should download those tools:

Launching the server and adding the XML file to the native database :

let’s begin our project ,we should create a xml file for example called persons.xml in whish we add some person elements ,each person has different nodes(first name,last name,email ,age) this is an example of persons.xml :

< persons >

< person id=”1″ >

< fname > FOUAD < /fname >

< lname > SAIDY < /lname >

< email > fouadsaidy@gmail.com < /email >

< age > 22 < /age >

< /person >

< person id=”2″ >

< fname > KEVIN < /fname >

< lname > MITNICK < /lname >

< email > kevin.mitnick@gmail.com < /email >

< age > 45 < /age >

< /person >

< person id=”3″ >

< fname > BILL < /fname >

< lname > GATES < /lname >

< email > bill.gates@gmail.com < /email >

< age > 55 < /age >

< /person >

< /persons >

We created the xml file let’s now store this file in Xindice database ,to do that we should start the server, open the Xindice Folder called xindice-1.0 –>launch startup.bat, to verify if the server is executed correctly open your navigator and show http://localhost:4080/ page if you saw an xindice page that means the server is launched without errors.

The Server Is Running

Apache XIndice Start Page

Next step is to launch Xindice Browser which give us many options to look to the database (open XindiceBrowser and execute XIndiceBrowser.bat
To add the Xml file to the XML database we should create a Collection in whish we will store this file:

Create a Test Collection

Now let’s add persons.xml file to the new collection :

Add XML File To Test Collection

Add persons.xml to Test collection

show persons.xml in XIndice Browser

we finished the first step of configuration and insertion of XML file in native database,next step is to create a javaa classe wishes manipulate the XML file stored in the database.

Update XML database in java

open Eclipse Galileo IDE and create a new Java Project called test_xindice ,click the right mouse into the project and select Properties , in the properties window select Java Build Path –> Libraries , then click the Add External JARs… Button , select the 5 jar’s in the java–> lib folder (see the next image)

Add Jars To Java Project

show persons.xml in XIndice Browser

Download xupdate.java

add a new person : -A persons farid safiri 25 farid@gmail.com
Remove the 4th person : -R persons 4
update the second person : -E persons 2 steve Mcarty 21 sMcarty@gmail.com

after writhing one of those case in the argument section click run, you will see the xupdate code in the eclipse console, for example if we write the first option adding a new person to the persons.xml file stored in the database we will see the request like this :

add Arguments to Eclipse run configuration

The code produced by the program and executed in the server :

XUpdate code sent to the server

for more informations about how to use XUpdate UseCases

now let’s see the modification in Xml database, move to XIndice Database Browser click the refresh button and select persons.xml file you will see that the forth person is added to the database :

XML Database updated

In the same way you can execute author options of removing or updating an element in the XML database .

Execute XPath expression in java

To learn XPath : XPath Tutorial

create a simple java class called show_xml and copy this file to your class:
show_xml.java
execute this file and you will see the result in eclipse console like this :

XPath Result

Step By Step Create Simple Calculator using Eclipse Galileo & EJB 3.0

admin — Sat, 30 Jan 2010 12:41:44 +0000

Remark:

I received many emails that talk about the error of “Firstcalc not bound” the problem that if you didn’t referenced the EJB project in the web application your server can not know the calcImpl class for this reason it shows this error.
To resolve this error just try to remove @Stateless(mappedName = “Firstcalc”) and replace it by @stateless,in the naming function in the servlet replace calc cl = (calc) ctx.lookup(”Firstcalc”); by cl=(calc) ctx.lookup(”calcImpl/local”);
I used the bounding without a mapped name of the calcImpl class, it’s Work correctly(tested with jboss server).

This tutorial is available in pdf book : Step By Step Create Simple Calculator using Eclipse Galileo & EJB 3.0

We will use in this tutorial:

we will create an application in the server side based on EJB 3.0, and an author web client application

Server Application Using EJB:

Configuration JBoss Server:

The second step is to configuarate the Jboss server in Eclipse Galieo IDE:

in Eclipse Menu choose Window–> Preferences, then choose
Server –> Runtime Environments.

click add Button then choose JBoss–> JBoss v5.0 and check” Create a new local server”

In Application Server Directory select the JBoss Server directory,
not the Content of the directory! :

you added the Jboss Server to Eclipse , now let’s add the Jboss Server
to this section:

select the Server section clik and choose new->Server then next next
until finish

the server appears like this in Server section:

Now we will verify that Jdk is the default installed JRE’s :

select Window–>Preferences in this windows select Java–> Installed JREs
then if jdk is not checked check it ,or add it if it doesn’t exist:

we finished configuration step let’s move now to programming an
EJB Application.

EJB Application:

in this application we will create :

Remote Interface calc,

Class calcImpl which implements calc.

select File–>New–> Other.. then create EJB Project :

specify the name of the project for example SimpleCalculator , and choose the JBoss v5 in target field:

now we created a simple ejb project ,we will create source code in ejbModule directory :

we finished creating EJB project, create the interface calc with package first :

add this code to your calc interface:

package ejb;

import javax.ejb.Local;

@Local

public interface calc {

public float sum(float a,float b);

public float mult(float a,float b);

public float minus(float a,float b);

public float div(float a,float b);

}

next step is to create calcImpl with the same way dont forgit to specify the same package (ejb), and add this code to class:

package ejb; import javax.ejb.Stateless;
@Stateless(mappedName=”Firstcalc”)

public class calcImpl implements calc {
public float sum(float a,float b)
{ return a+b; }
public float mult(float a,float b)
{ return a*b; }
public float minus(float a,float b)
{ return a-b; }
public float div(float a,float b) {
try {
return a/b;
}catch(Exception e){
System.out.println(”Error:devision by 0!!”);
return 0;
}
}
}

now we finished EJB Application let’s move to The Web Client Application.

Web Client Application:

select File–>New–>Dynamic Web Project , it’s name: SimpleCalculatorWeb

add a jsp page called index to the WebContent directory :

add this form to index.jsp:

Hello World To The Simple Calculator

<% float a=2,b=1;
if (request.getAttribute(”a”)!=null)
a=Float.parseFloat(request.getAttribute(”a”).toString());
if( request.getAttribute(”b”)!=null)
b=Float.parseFloat(request.getAttribute(”b”).toString()); %>

Result is: <%=session.getAttribute(”result”)%>

Error: <%=session.getAttribute(”error”)%>

now create a calServlet with web package in the JavaResources :src directory :

servlet is created like this:

add those import to your servlet class:

import java.io.IOException;
import javax.naming.*;
import javax.servlet.*;
import javax.servlet.*;
import javax.servlet.http.*;

copy this code to the doGet function :

HttpSession session=request.getSession(true);
RequestDispatcher rd=this.getServletContext().getRequestDispatcher(”/index.jsp”);

float a=Float.parseFloat(request.getParameter(”n1″));
float b=Float.parseFloat(request.getParameter(”n2″));
char oper=request.getParameter(”oper”).charAt(0);
float result=0;
try {
Context ctx=new InitialContext();
// call the calcImpl class of the SimpleCalculator EJB with the mappedName
calc cl=(calc) ctx.lookup(”Firstcalc”);
switch(oper)
{
case ‘+’: result=cl.sum(a, b); break;
case ‘-’: result =cl.minus(a, b); break;
case ‘*’: result =cl.mult(a, b); break;

case ‘/’: result =cl.div(a, b); break;
}
session.setAttribute(”result”,result); request.setAttribute(”a”, a); request.setAttribute(”b”, b);
}catch(NamingException e){
session.setAttribute(”erreur: “,e.getMessage());
}
rd.forward(request,response);

to let the the web client application to know the calc interface we must configure the build path of the project in adding the first project SimpleCalculator :

in the project section click add and select SimpleCalculator:

now add this import to your servlet class :
import ejb.calc;

let’s deploy the two project ,firstly play the JBoss Server in Server section:

deploying the EJB Project :

with the same way deploy SimpleCalculatorWeb:

if you have any remarks or questions dont hesitate to post it.