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EJB and other Jakarta /Java EE Technologies

EJB, JSPs and JDBCs

Greenhorn

Posts: 14

posted 16 years ago

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Hello,

I'm new to EJBs and I've trying to create a web application which basically i'm just starting from the login page

I have created a message bean, entity bean and session bean for my user.

Then i created a jsp page which accepts the user's login username and password

I don't know how to check these details which those in the jdbc database :S

any help how i can connect to this jdbc database?

thnx a lot!

Charlie Jones

Greenhorn

Posts: 14

posted 16 years ago

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btw my message bean is shown below:

package ejb;

import javax.annotation.Resource;
import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.ejb.MessageDrivenContext;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.ObjectMessage;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@MessageDriven(mappedName = "jms/member", activationConfig =  {
        @ActivationConfigProperty(propertyName = "acknowledgeMode", propertyValue = "Auto-acknowledge"),
        @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue")
    })
public class MemberMessageBean implements MessageListener {

@Resource
    private MessageDrivenContext mdc;
    @PersistenceContext
    private EntityManager em;

public MemberMessageBean() {
    }

public void onMessage(Message message) {
        ObjectMessage msg = null;
        try {
            if (message instanceof ObjectMessage) {
                msg = (ObjectMessage) message;
                Members e = (Members) msg.getObject();
                save(e);
            }
        } catch (JMSException e) {
            e.printStackTrace();
            mdc.setRollbackOnly();
        } catch (Throwable te) {
            te.printStackTrace();
        }
    }

public void save(Object object) {
        em.persist(object);
    }
    
}

Ulf Dittmer

Rancher

Posts: 43081

posted 16 years ago

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I'm confused. If I understand the question correctly, the problem is how to use JDBC to check login data in a database - correct? If so, what does all the talk about various EJBs have to do with it?

Are you familiar with JDBC? Do you have the driver for whatever DB you're using?

Charlie Jones

Greenhorn

Posts: 14

posted 16 years ago

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In simple terms what I'm trying to do is this:
http://www.netbeans.org/kb/60/javaee/ejb30.html

but with JSPs...

I tried it with servlets and it worked but i couldnt get it to work with jsps :s

Reza Rahman

author

Posts: 580

posted 16 years ago

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Charlie,

Can you kindly post the code for the JSP and/or the Servlet?

Thanks,
Reza

Independent Consultant — Author, EJB 3 in Action — Expert Group Member, Java EE 6 and EJB 3.1

Charlie Jones

Greenhorn

Posts: 14

posted 16 years ago

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This is my REGISTER JSP:
Where the new user is supposed to enter details about him/herself

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <h1>Hello World!</h1>
        <form action="ProcessRegister.jsp" method="POST">
            First Name     :
            <input type="text" name="firstname">
            <br>
            Surname        :
            <input type="text" name="surname">
            <br>
            Email Address  :
            <input type="text" name="email">
            <br>
            Country        :
            <input type="text" name="country">
            <br>
            User name      :
            <input type="text" name="username">
            <br>
            Password       :
            <input type="password" name="password">
            <br>
            Retype password:
            <input type="password" name="password2">
            <br>

then this processes the register:

<%@taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql"%>

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<%
        
        ConnectionFactory connectionFactory;

Context ctx = new InitialContext();

QueueConnectionFactory queueConnectionFactory =
(QueueConnectionFactory) ctx.lookup("QueueConnectionFactory");
        
        Queue queue;

String username = request.getParameter("username");
        String password = request.getParameter("password");
        String password2 = request.getParameter("password2");

//if the user name does not exist
        //and the passwords are equal
        boolean valid = checkUser.validate(username, password, false);

boolean equal = false;
        if (password.equals(password2)) {
            equal = true;
        }
        else {
            equal = false;  %>
            <jsp:forward page="Register.jsp"></jsp:forward>
           <% }

if (valid == true) {
            %>
            <jsp:forward page="Register.jsp"></jsp:forward>
            <%
            }

if ((valid == false) && (equal == true)){
             try {

Connection connection = connectionFactory.createConnection();
                Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
                MessageProducer messageProducer = session.createProducer(queue);

ObjectMessage message = session.createObjectMessage();
                // here we create NewsEntity, that will be sent in JMS message
                Members member = new Members();

message.setObject(member);
                messageProducer.send(message);
                messageProducer.close();
                connection.close();

} catch (JMSException ex) {
                ex.printStackTrace();
            }
        }

<jsp:forward page="WelcomePage.jsp"></jsp:forward>
            <%
            }

//add to entity bean
    %>

</body>
</html>

Charlie Jones

Greenhorn

Posts: 14

posted 16 years ago

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by the way, im making use of the javadb derby database - the jdbc/sample

Charlie Jones

Greenhorn

Posts: 14

posted 16 years ago

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so in other words I'm asking how to persist my new member to the jdbc/sample table called Members from a JSP.

The entity i am using for the members is called Members

Thnx

Reza Rahman

author

Posts: 580

posted 16 years ago

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You have a few options:

1. Use JNDI lookups inside the JSP to get a reference to the session bean to insert the record.
2. Use a Servlet handler/controller to inject the session bean via @EJB.
3. Use a JSF backing bean to inject the session bean via @EJB.

I would recommend option 3 if this is a real-life application, quite possibly with Seam. Option 1 would be acceptable for beginner code to learn the internals of the technology but really should be avoided in real life. If you are very averse to using JSF, I would suggest option 2. Another alternative is to use something like Struts 2. You may inject EJBs into Struts Actions with minimal effort. No technology will allow you to inject EJBs into JSPs. As of Java EE 6, JSP is mostly regarded as a legacy technology in favor of JSF/Facelets.

Look to the documentation of your application server on how to perform a JNDI look-up of a session bean if you opt to use JSP only.

Hope it helps,
Reza

Independent Consultant — Author, EJB 3 in Action — Expert Group Member, Java EE 6 and EJB 3.1

Charlie Jones

Greenhorn

Posts: 14

posted 16 years ago

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Thnx very much!

I'll give them a go tonight hopefully I'll see something working.

Charlie Jones

Greenhorn

Posts: 14

posted 16 years ago

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can I use useBean here??

Reza Rahman

author

Posts: 580

posted 16 years ago

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Charlie,

The useBean tag is not designed to access EJB directly. However, while using Seam, you can use EJB 3 session beans as backing beans through bean binding. In a plain JSP world, the class in the useBean tag would have to do a JNDI look-up for the EJB.

Hope it helps,
Reza

Independent Consultant — Author, EJB 3 in Action — Expert Group Member, Java EE 6 and EJB 3.1

Charlie Jones

Greenhorn

Posts: 14

posted 16 years ago

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ohh I see.

Thank you very much!

Good day!

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