hellobean.java

EJB实践的服务器是用SUN的服务器

package examples;

import javax.ejb.SessionContext;
import javax.ejb.*;
import javax.naming.*;
import java.rmi.*;
import javax.rmi.*;
import java.util.*;

/**
 * Demonstration stateless session bean.
 *
 * @ejb.bean
 *     name="HelloWorld"
 *     type="Stateless"
 *     jndi-name="HelloHome"
 *
 * @ejb.interface
 *     remote-class="examples.Hello"
 *     local-class="examples.HelloLocal"
 *
 * @ejb.home
 *     remote-class="examples.HelloHome"
 *     local-class="examples.HelloLocalHome"
 *
 */
public class HelloBean implements javax.ejb.SessionBean
{
    //
    // EJB-required methods
    //
    public void ejbCreate()
    {
        System.out.println("ejbCreate()");
    }

    public void ejbRemove()
    {
        System.out.println("ejbRemove()");
    }

    public void ejbActivate()
    {
        System.out.println("ejbActivate()");
    }

    public void ejbPassivate()
    {
        System.out.println("ejbPassivate()");
    }

    public void setSessionContext(SessionContext ctx)
    {
        System.out.println("setSessionContext()");
    }

    //
    // Business methods
    //
    public String hello()
    {
        System.out.println("hello()");
        AccountLocal account;
        try
        {
            Context ctx = new InitialContext();			
            Object obj = ctx.lookup("java:comp/env/ejb/AccountHome");
            AccountLocalHome home =(AccountLocalHome)javax.rmi.PortableRemoteObject.narrow(obj, AccountLocalHome.class);

            System.err.println("Total of all accounts in bank initially = " + home.getTotalBankValue());

            /*
             * Use the factory to create the Account EJB Object
             */
            home.create("123-456-7890", "John Smith"); 
            /*
             * Find an account
             */
            Iterator i = home.findByOwnerName("John Smith").iterator();
            if (i.hasNext()) 
            {
                account = (AccountLocal)javax.rmi.PortableRemoteObject.narrow(i.next(), AccountLocal.class);
            }
            else 
            {
                throw new Exception("Could not find account");
            }

            /*
             * Call the balance() method, and print it
             */
            System.out.println("Initial Balance = " + account.getBalance());

            /*
             * Deposit $100 into the account
             */
            account.deposit(100);

            /*
             * Retrieve the resulting balance.
             */
            System.out.println("After depositing 100, account balance = " + account.getBalance());

            System.out.println("Total of all accounts in bank now = " + home.getTotalBankValue());

            /*
             * Retrieve the Primary Key from the EJB Object
             */
            AccountPK pk = (AccountPK) account.getPrimaryKey();

            /*
             * Release our old EJB Object reference.  Now call
             * find() again, this time querying on Account ID
             * (i.e. the Primary Key).
             */
            account = null;
            account = home.findByPrimaryKey(pk);

            /*
             * Print out current balance
             */
            System.out.println("Found account with ID " + pk +".  Balance = " + account.getBalance());

            /*
             * Try to withdraw $150
             */
            System.out.println("Now trying to withdraw $150, which is more than is currently available.  This should generate an exception..");
            account.withdraw(150);
           
            return "Hello, World!";
        }
        catch (Exception e) 
        {
            e.printStackTrace();
            return "Exception";
        }        
    }
}