getpasswordhintservlet.java

高级java2 大学教程(含源码,经典的Java学习教程

// GetPasswordHintServlet.java
// GetPasswordHintServlet allows a customer to retrieve a 
// lost password.
package com.deitel.advjhtp1.bookstore.servlets;

// Java core packages
import java.io.*;

// Java extension packages
import javax.servlet.*;
import javax.servlet.http.*;
import javax.naming.*;
import javax.ejb.*;
import javax.rmi.*;

// third-party packages
import org.w3c.dom.*;

// Deitel packages
import com.deitel.advjhtp1.bookstore.model.*;
import com.deitel.advjhtp1.bookstore.ejb.*;

public class GetPasswordHintServlet extends XMLServlet {
   
   // respond to HTTP get requests
   public void doGet( HttpServletRequest request,
                      HttpServletResponse response )
      throws ServletException, IOException
   {
      Document document = getDocumentBuilder().newDocument();
      String userID = request.getParameter( "userID" );
      
      // get password hint from Customer EJB
      try {
         InitialContext context = new InitialContext();
         
         // look up Customer EJB
         Object object = 
            context.lookup( "java:comp/env/ejb/Customer" );
         
         CustomerHome customerHome = ( CustomerHome )
            PortableRemoteObject.narrow( object,
               CustomerHome.class );
         
         // find Customer with given userID
         Customer customer = 
            customerHome.findByUserID( userID );
         
         // create passwordHint element in XML document
         Element hintElement = 
            document.createElement( "passwordHint" );
         
         // add text of passwordHint to XML element
         hintElement.appendChild( document.createTextNode( 
            customer.getPasswordHint() ) );
         
         // append passwordHint element to XML document
         document.appendChild( hintElement );
         
      } // end try
      
      // handle exception when looking up Customer EJB
      catch ( NamingException namingException ) { 
         namingException.printStackTrace(); 
         
         String error = "The Customer EJB was not found in " +
            "the JNDI directory.";
         
         document.appendChild( buildErrorMessage(
               document, error ) );
      }
      
      // handle exception when Customer is not found
      catch ( FinderException finderException ) { 
         finderException.printStackTrace(); 
         
         String error = "No customer was found with userID " +
            userID + ".";
         
         document.appendChild( buildErrorMessage( 
               document, error ) );
      }
      
      // ensure content is written to client
      finally { 
         writeXML( request, response, document ); 
      }
      
   } // end method doGet
}

/***************************************************************
 * (C) Copyright 2002 by Deitel & Associates, Inc. and         *
 * Prentice Hall. All Rights Reserved.                         *
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 * efforts include the development, research, and testing of   *
 * the theories and programs to determine their effectiveness. *
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 * expressed or implied, with regard to these programs or to   *
 * the documentation contained in these books. The authors     *
 * and publisher shall not be liable in any event for          *
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