JPA, EJB and Web Application

[Prateek Jauhari]

Is there any tutorial or example for using JPA and EJB3.0 and test client as a servlet or struts action class.
I am trying to save value in database using a stateless session bean and JPA and the invoke that session bean in servlet.

Here is my entity class

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package entity;

import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;

/**
 *
 * @author Administrator
 */
@Entity
@Table(name = "customer", catalog = "test", schema = "")
@NamedQueries({
    @NamedQuery(name = "Customer.findAll", query = "SELECT c FROM Customer c"),
    @NamedQuery(name = "Customer.findById", query = "SELECT c FROM Customer c WHERE c.id = :id"),
    @NamedQuery(name = "Customer.findByName", query = "SELECT c FROM Customer c WHERE c.name = :name")})
public class Customer implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "ID", nullable = false)
    private Integer id;
    @Basic(optional = false)
    @Column(name = "Name", nullable = false, length = 45)
    private String name;

    public Customer() {
    }

    public Customer(Integer id) {
        this.id = id;
    }

    public Customer(Integer id, String name) {
        this.id = id;
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Customer)) {
            return false;
        }
        Customer other = (Customer) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "entity.Customer[id=" + id + "]";
    }

}

Here Is my session bean

package session;

import entity.Customer;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

/**
 *
 * @author Administrator
 */
@Stateless(mappedName="customerBeanRemote")
public class CustomerBean implements CustomerBeanRemote {

    @PersistenceContext
    EntityManager em;

    public void saveCustomer(String name)
    {
        Customer cust = new Customer();
        cust.setName(name);
        em.persist(cust);
    }
 
}


package session;

import javax.ejb.Remote;

/**
 *
 * @author Administrator
 */
@Remote
public interface CustomerBeanRemote extends CustomerInf{
    
}

package session;

/**
 *
 * @author Administrator
 */
public interface CustomerInf {
public void saveCustomer(String name);
}

This is my servlet

package customer;

import java.io.IOException;
import java.io.PrintWriter;
import javax.ejb.EJB;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import session.CustomerInf;

/**
 *
 * @author Administrator
 */
public class module1 extends HttpServlet {

     @EJB(mappedName = "customerBeanRemote")
     CustomerInf cus;
    /** 
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
            String name = request.getParameter("name");
            out.println("Name: "+name);
            cus.saveCustomer(name);
        } finally { 
            out.close();
        }
    } 

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** 
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    } 

    /** 
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    /** 
     * Returns a short description of the servlet.
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}

I am using JBoss 5.1GA application server, MySQL and Netbeans 6.9.1 IDE


I am not able to get this thing worked...
Any help please ...
I need this thing up badly...

Thanks In Advance..

Regards
Prateek

[Arun Kumarr]

Are you getting any exceptions?

[Prateek Jauhari]

I am not able to deploy the bean over the server..
Each time I do a deployment, I get a new Exception.

[Prateek Jauhari]

Is there any hot redeployment issues with JBoss AS 5.1.0GA...
or any other issue with this server...?