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EJB 3.0 |
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Note that, the @Remote annotation decorating
the interface definition. This lets the container
know that remote clients will access CalculatorBean.
(ii) Coding the Enterprise Bean Class
The enterprise bean class for this example is
called CalculatorBean. This class implements
the four business methods (add, subtract,
multiply, division) that are defined in the CalculatorRemote business interface. The
source code for the CalculatorBean class is
given below.
package
com.javajazzup.examples.ejb3.stateless;
import java.math.*;
import javax.ejb.Stateless;
import javax.ejb.Remote;
@Stateless(name=”CalculatorBean”)
@Remote(CalculatorRemote.class)
public class CalculatorBean implements
CalculatorRemote{
public float add(float x, float y){
return x + y;
}
public float subtract(float x, float y){
return x - y;
}
public float multiply(float x, float y){
return x * y;
}
public float division(float x, float y){
return x / y;
}
} |
Note that, the @Stateless annotation decorating
the enterprise bean class. This lets the container
know that CalculatorBean is a stateless session
bean.
2. Creating a Web Client
The web client is divided into two pages. First
is “form.jsp” where a request form is sent to the client; second is “WebClient.jsp” which is
called from the “form.jsp” page.
A JSP page is a text-based document that
contains JSP elements, which construct dynamic
content, and static template data, expressed in any text-based format such as HTML, WML,
and XML. |
|
The source code for the “form.jsp” is given
below.
<html>
<head>
<title>Calculator</title>
</head>
<body bgcolor=”pink”>
<h1>Calculator</h1>
<hr>
<form action=”WebClient.jsp”
method=”POST”>
<p>Enter first value:
<input type=”text” name=”num1"
size=”25"></p>
<br>
<p>Enter second value:
<input type=”text” name=”num2"
size=”25"></p>
<br>
<b>Seclect your choice:</b><br>
<input type=”radio” name=”group1" value
=”add”>Addition<br>
<input type=”radio” name=”group1" value
=”sub”>Subtraction<br>
<input type=”radio” name=”group1" value
=”multi”>Multiplication<br>
<input type=”radio” name=”group1" value
=”div”>Division<br>
<p>
<input type=”submit”
value=”Submit”>
<input type=”reset”
value=”Reset”></p>
</form>
</body>
</html> |
The following statements given below in “WebClient.jsp” are used for locating the
business interface, creating an enterprise bean
instance, and invoking a business method.
InitialContext ic = new InitialContext();
CalculatorRemote calculator =
(CalculatorRemote)ic.lookup(“example/
CalculatorBean/remote”);
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Jan 2008 | Java Jazz Up | 18 |
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