Ramanjaneyulu Dayinaboyina: ENTERPRISE JAVA BEANS

20, జనవరి 2014, సోమవారం

ENTERPRISE JAVA BEANS

http://jaiswaltraining.com/ejb3/weblogic/ch1.php

Stateless Session Bean

EJB3 in Weblogic10.3 with client example in Eclipse

EjbSession Project creation

Take a new EJB project
Now take a session bean
Give it name Hello.
It creates two files

Hello.java(Remote interface)
HelloBean.java(Stateless bean)

Now modify the code for the remote interface
Put the business logic in it as shown below.
In this examplewe have added one method hello.

package example;



import javax.ejb.Remote;



@Remote

public interface Hello{  

  public String hello(String h);

}

Now implements the remote interface Hello.
In the bean file override the method hello.
You can add the following attributes of the Stateless bean

name
mappedName
description

But in our programm we will use only attribute mappedName
Add the attribute value Hello .
This mappedName value Hello will be used in the Client code.

package example;



import javax.ejb.Stateless;



@Stateless(mappedName="Hello")

public class HelloBean implements Hello {



  public String hello(String h) {

    return "Hello  " + h + "  !";

  }

}

Ejb3 application deployment

Right click on the given project
Select Run As-->Run On Server.
Select Oracle Weblogic Server.
Click on the finish button.
It starts the server and deploy the given project

WebClient

Now we will create a web client for the given Ejb program.
Create a Dynamic Web project
Put it name as ejb3webclient.

Setting build path for EJB3

Right Click on the Web project as shwon below
Select Build Path-->Configure Build Path.

In the opening window navigate to the Projects tab.
Now we can set the required project in its build path.
Click on the Add button.
Select the ejb3 project.
Click on the Ok.

Now create one file client.jsp.
Add the following code in it.
This jsp file is having two part

One form part
Businesss logic part

Upon clicking on submit button the form will call the business code.
This form is calling itself.

<%@ page import="example.* , javax.naming.* , java.text.*, java.util.Properties" %>



<%!

  private Hello hel=null;

  public void jspInit()

  {

    try

    {

      Properties p=new Properties();

      p.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");

      p.put(Context.PROVIDER_URL,"t3://localhost:7001");

      InitialContext ctx=new InitialContext(p);

      hel=(Hello)ctx.lookup("Hello#example.Hello");

    }

    catch(Exception e)

    {

      e.printStackTrace();

    }

  }

%>

<%

  String result=null;

  String name=null;

  try 

  {

    name=request.getParameter("name");

    if(name!=null)

      result=hel.hello(name);

  }

  catch(Exception e)

  {

    result="Not Valid";

  }

%>



<html>

<head>

<title>Example of Stateless Session Bean</title>

</head>

<body>

<h1>

Using Stateless Session Bean</h1>

<br><br>

<form action="client.jsp" method="POST">

Enter Your Name : <input type="text" name="name">

<br><br><input type="submit" value="Submit"><br><br>

</form>

<%

if(result!=null)

out.println("<b>"+result+"</b>");

%>

</body>

</html>