I can't use Entity Class (JPA) in Netbeans7.0 .

**mmc01** · 08-19-2011, 08:28 AM

I tried to use Entity Class (JPA) in Netbeans7.0 but It doesn't work.

1. I create Enterprise Application name BookApp.

Create Entity Class

2. I right click at BookApp-ejb and select Entity Classes fron Database.
3. In dialog New Entity Class from Database I insert JNDI Name:jdbc/test for connect to test database and select table books. After that ,I click Next for insert Package: entity and click Finish.

Create Session Bean

4. I right click at BookApp-ejb and select Session Beans for Entity Classes and click Next.
5. I click Add All >> and click Next.
6. I insert Package: sb , create Interface:Local and click Finish.

Create Web Application

7. I right click BookApp-war and select HTML insert HTML File Name :findBook and click Finish.
8. I put this code in HTML file

Java Code:

<form action="ShowBook" method="POST">
<h2>Search Book from ISBN </h2>
Enter ISBN <input type="text" name="isbn" value="" />
<input type="submit" value="Find" />
</form>

9. I right click BookApp-war and select Servlet insert File Name: ShowBook, Package: servlets and click Finish.
10. I right click in editor and select Insert Code… > Call Enterprise Bean…
11. In dialog Call Enterprise Bean I select BooksFacade and click OK.
12. I uncomment html and insert this code between out.println("<body>");

Java Code:

String isbn = request.getParameter("isbn");
Books book = booksFacade.find(isbn);
out.println("Title: " + book.getTitle()+ "<BR>");
out.println("Author: " + book.getAuthor() + "<BR>");
out.println("Price: " + book.getPrice() + "<BR>");

13. I clean and build BookApp.
14. I run BookApp.
15. I go to this URL http://localhost:8080/BookApp-war/findBook.html and insert isbn from books table but when I click Find button It show error like this.

HTTP Status 500 -

type Exception report

message

descriptionThe server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.ejb.EJBException

I don't know what I mistake. I delete Session Beans and create Session beans again but no create Interface. when I run BookApp it show same error. I'm new for EJB. please help me.