JSF 2.0: Interaction between several Java classes (get value)

Question

Hi Everybody!
Unfortunately, I find both in the web and in books not really advice. And slowly I have the feeling that something is either really lazy or I'm just incapable! :-)
Following scenario:
Suppose I have a JSF page (.xhtml-file) that has several input fields (<h:inputText... />). For example, a field for the lastname (with the corresponding Java class: Customer.java) and a field for the ordered product (with the corresponding Java class: Shoppingcart.java). In addition, the page has a Save button to store the entered data into the database (with the corresponding Java class: Jdbc.java).
Code of JSF page:
<table>
  <tr>
    <td><h:inputText id="lastname" value="#{customer.lastname}" /></td>
  </tr>
  <tr>
    <td><h:inputText id="product" value="#{shoppingcart.product}" /></td>
  </tr>
  <tr>
    <td><h:commandButton action="#{jdbc.insertDataIntoDB}" value="Save" /></td>
  </tr>
</table>Code of Customer.java class:
@ManagedBean (name = "customer")
@SessionScoped
public class Customer
   private String lastname;
   public String getLastname()
      return lastname;
   public void setLastname(String lastname)
     this.lastname = lastname;
}Code of Shoppingcart.java class:
@ManagedBean (name = "shoppingcart")
@SessionScoped
public class Shoppingcart
   private String product;
   public String getProduct()
      return product;
   public void setProduct(String product)
     this.product = product;
}Code of Jdbc.java class:
@ManagedBean (name = "jdbc")
@SessionScoped
public class Jdbc
   public String insertDataIntoDB()
      Connection conn = null;
      Statement  stmt = null;
      try
         Class.forName("com.mysql.jdbc.Driver");
         conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/db_xyz", "username", "pw");
         stmt = conn.createStatement();
         stmt.executeUpdate("INSERT INTO db_xyz.tbl_orders (Lastname, Product) VALUES (" + lastname + "," + product + ");");
}Please ignore the last line (stmt.executeUpdate) of my code in the jdbc class. This does not work.
And right here is just my problem!
How do I get in my Jdbc class the current values of the entered lastname and product?
I'll be very grateful if you could help me in this regard.
Many greetings and thanks in advance.
Edited by: Fools on Sep 13, 2010 5:48 AM

Answer 1

One approach is to have a backing bean for each JSF. Say you have shoppingPage.jsf, you could also have a managed bean called ShoppingPage. If this bean holds references to the other beans then it is easy to reference everything via the first bean.
class ShoppingPage {
     private DataBase db;
     private ShoppingCart sc;
     //getters and setters, etc
}The JSF can refer to the ShoppingCart via the ShoppingCart i.e. #{ shoppingPage.sc.doSomeThing() }
If both db and sc are involved then #{ shoppingPage.save() } where the save function is in the ShoppingCart object and can see both of the other objects.
Otherwise it get a bit complicated because there may be several users on your website so you need to identify the objects relating to a particular user. Take a look at http://balusc.blogspot.com/2006/06/communication-in-jsf.html