addressmaintenancebean.java

此程序都是企业级 的数据库开发程序 全面揭示了JAVA对数据库的操作

package mvc.addressmaintenance;

/* Standard Java Classes */
import java.rmi.RemoteException;
import java.util.Collection;
import java.util.Iterator;
import java.io.File;

/* Imported from the J2EE or JBoss ejb.jar and servlet.jar files */
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
import javax.naming.InitialContext;
import javax.servlet.http.HttpServletRequest;

/* Imported from the xerces.jar file */
import org.w3c.dom.Document;                 /* W3C Interfaces */
import org.w3c.dom.Element;
import org.apache.xerces.dom.DocumentImpl;   /* Xerces DOM Classes */

/* Class files for the chapter */
import mvc.templates.*;
import mvc.MVCHelper;
import mvc.entitybeans.customers.*;
import mvc.entitybeans.postalcodes.*;
import mvc.custlist.*;


public class AddressMaintenanceBean implements MVCBean {

  /*
   * The retrieve method for the AddressMaintenanceBean is using the Customers
   * and PostalCodes entity beans to retrieve a customer address record and build an XML document to return
   * back to the calling application.
   */
  public Document retrieve(HttpServletRequest _request) 
          throws RemoteException, Exception {
    Integer customerId = new Integer(_request.getParameter("customerId"));

    InitialContext ctx = new InitialContext();
    CustomersHome customersHome = (CustomersHome) ctx.lookup("Customers");
    Customers customers = customersHome.findByPrimaryKey(customerId);

    PostalCodesHome postalCodesHome = 
      (PostalCodesHome) ctx.lookup("PostalCodes");
    PostalCodes postalCodes = 
      postalCodesHome.findByPrimaryKey(customers.getCustomerPostalCode());

    return buildXML(customers, postalCodes, ctx);
  } 

  /*
   * The buildXML method will build an XML document based on the values
   * stored in the internal class variables.  It will then query the
   * music record database and retrieve a list of all of the Postal Codes
   * stored within the postal codes table.  These postal codes are used to
   * populate the dropdown box seen in the address maintenance screen.
   */
  private Document buildXML(Customers _customers, PostalCodes _postalCodes, 
                            InitialContext _ctx) throws Exception {
    Document xmlDoc = new DocumentImpl();

    /* Creating the root element */
    Element rootElement = xmlDoc.createElement("CUSTOMERS");
    Element customer = xmlDoc.createElement("CUSTOMER");

    xmlDoc.appendChild(rootElement);
    customer.setAttribute("customerid", 
                          _customers.getCustomerId().toString());

    /* Adding my different elements to the customer record */
    customer.appendChild(MVCHelper.buildDBElement(xmlDoc, 
            "CUSTOMERFIRSTNAME", _customers.getCustomerFirstName()));
    customer.appendChild(MVCHelper.buildDBElement(xmlDoc, 
            "CUSTOMERLASTNAME", _customers.getCustomerLastName()));
    customer.appendChild(MVCHelper.buildDBElement(xmlDoc, 
            "CUSTOMERADDRESS1", _customers.getCustomerAddress1()));

    customer.appendChild(MVCHelper.buildDBElement(xmlDoc, 
            "CUSTOMERADDRESS2", _customers.getCustomerAddress2()));

    customer.appendChild(MVCHelper.buildDBElement(xmlDoc, "CUSTOMERCITY", 
            _customers.getCustomerCity()));
    customer.appendChild(MVCHelper.buildDBElement(xmlDoc, "CUSTOMERSTATE", 
            _postalCodes.getStateProv()));
    customer.appendChild(MVCHelper.buildDBElement(xmlDoc, "CUSTOMERZIP", 
            _postalCodes.getPostalCode()));

    rootElement.appendChild(customer);

    /*
     * Retrieving all of the postal codes stored within the music record database and
     * appending this onto the customer's document root object.
     */
    rootElement.appendChild(buildPostalCodes(xmlDoc, _ctx));
    return xmlDoc;
  } 

  /*
   * The buildPostalCodes method will build the <POSTALCODES></POSTALCODES>
   * piece of the <CUSTOMERS>...</CUSTOMERS> XML DOM that is returned to
   * the code calling the toXML() method on this class.
   */
  private Element buildPostalCodes(Document _xmlDoc, 
                                   InitialContext _ctx) throws Exception {
    PostalCodesHome postalCodesHome = 
      (PostalCodesHome) _ctx.lookup("PostalCodes");
    Collection postalCodeCollections = postalCodesHome.findAll();

    /* Appending individual <POSTALCODE> elements to to <POSTALCODES> */
    Iterator iterator = postalCodeCollections.iterator();

    /* Building the <POSTALCODES> XML Element */
    Element postalCodesElement = _xmlDoc.createElement("POSTALCODES");
    Element postalCodeElement = null;

    while (iterator.hasNext()) {
      PostalCodes postalCodes = (PostalCodes) iterator.next();

      postalCodeElement = _xmlDoc.createElement("POSTALCODE");
      postalCodeElement.setAttribute("postalcodeid", 
                                     postalCodes.getPostalCode());
      postalCodesElement.appendChild(postalCodeElement);
    } 

    return postalCodesElement;
  } 

  /*
   * The post method populates an AddressMaintenanceHelper class with data returned
   * from the music record database.  Since this screen returns to the CustomerList
   * screen after updating the record, it instantiates the CustomerList EJB and
   * performs a retrieve.
   */
  public Document post(HttpServletRequest _request) 
          throws RemoteException, Exception {
    Integer customerId = new Integer(_request.getParameter("customerId"));

    InitialContext ctx = new InitialContext();
    CustomersHome customersHome = (CustomersHome) ctx.lookup("Customers");
    Customers customers = customersHome.findByPrimaryKey(customerId);

    /*
     * Populating the customers object with data posted when the
     * user hit the Save button on the Address Maintenance screen.
     */
    customers
      .setCustomerAddress1(_request.getParameter("customerAddress1"));
    customers
      .setCustomerAddress2(_request.getParameter("customerAddress2"));
    customers.setCustomerCity(_request.getParameter("customerCity"));
    customers.setCustomerPostalCode(_request.getParameter("postalCode"));

    /*
     * Instantiating the CustomerList class and using it to return a refreshed
     * list of the Customer Records.
     */
    MVCHome customerListHome = (MVCHome) ctx.lookup("CustomerList");
    MVCObject mvcComponent = customerListHome.create();

    return mvcComponent.retrieve(_request);
  } 

  /*
   * Standard EJB Methods.  For simplicity's sake these methods have
   * been implemented as empty methods.
   */
  public void ejbCreate() {}
  public void ejbRemove() {}
  public void ejbActivate() {}
  public void ejbPassivate() {}
  public void setSessionContext(SessionContext sessionCtx) {}
}