day08.txt

网络购物系统开发详细步骤

========== 为index.jsp 添加购物功能  =============

1, 在dto中创建 OrderLine 类

package dto;
import dto.ProductDTO;
import java.io.Serializable;


public class OrderLine implements Serializable {

  private ProductDTO product= null;
  private int amount = 0 ;

  public OrderLine() {
  }

  public OrderLine( ProductDTO product,int amount ){
    this.product = product;
    this.amount = amount;
  }

  public ProductDTO getProduct(){
    return this.product;
  }
  public void setProduct( ProductDTO product ){
    this.product = product;
  }

  public int getAmount(){
    return this.amount;
  }
  public void setAmmount( int i ){
    this.amount = i;
  }

  public double getCost(){
    return product.getBasePrice() * amount;
  }

}

=========================================================

2，创建 ShoppingCartEJB：
	
   a)双击ejb  module 进入 ejb designer
   b)在ejb designer中点击右键 -->create ejb-->Session Bean

   c)修改session bean 属性：

      bean name             ：ShoppingCartEJB
      interface             : local	
      session type          : stateful
      session sychronization: true
      transaction type      ：Container

      --> class and package

      修改：
      package             : ejbs
      bean name           : ShoppingCartEJB
      bean class          : ejbs.ShoppingCartBean
      lcoal home interface: ejbs.ShoppingCartLocalHome
      local interface     : ejbs.ShoppingCartLocal

   d) 添加属性cart 用于保存OrderLine
      右键点击ShoppingCartEJB --> add --> field
      field name : cart
      type       : java.util.Collection
      getter     : none
      setter     : none
   e) 右键点击ShoppingCartEJB --> add --> Method
      依次添加五个方法：

      1） 
      method name    : addLine
      return type    : void
      input parameter: dto.OrderLine line
      interface      : local

      2） 
      method name    : getAll
      return type    : java.util.Collection
      input parameter: 
      interface      : local

      3） 
      method name    : removeLine
      return type    : void
      input parameter: String productId
      interface      : local

      4） 
      method name    : getCost
      return type    : double
      input parameter:
      interface      : local

      5） 
      method name    : getItemNumber
      return type    : int
      input parameter:
      interface      : local

    f) 右键点击ShoppingCartEJB --> view bean source

       1） 在ejbCreate方法中初始化cart属性
           public void ejbCreate() 
                   throws CreateException {
               cart = new ArrayList();
           }

       2） 为上述五个方法提供函数体：

           public void addLine(dto.OrderLine line) {
   
              cart.add( line );
           }

           public java.util.Collection getAll() {
                return cart;
           }

           public void removeLine(String productId) {
    
               Iterator i = cart.iterator();
    
              while( i.hasNext() ){
                 OrderLine line = (OrderLine)i.next();
                 if(line.getProduct().getProductId()
                               .equals( productId) ){
        
                       cart.remove(line);
                       break;
                }
              }
           }

           public double getCost() {
   
              double cost = 0;
              Iterator i = cart.iterator();
              while( i.hasNext() ){
                 OrderLine line = ( OrderLine ) i.next();
                 cost += line.getCost();
             }
             return cost;
          }

          public int getItemNumber() {
               return cart.size();
          }   

      g)  编译 OrderLine , ShoppingCartEJB
=========================================================

3, 为ShppingCartEJB 配置local ejb reference 
   a) 双击web.xml ,进入 webapp dd editor
   b) 点击左下角的local ejb reference    
   c) 选择 add 
      reference name : ejb/cartEJB
      type           : session           
      link           : ShoppingCartEJB
      local home interface: ejbs.ShoppingCartLocalHome
      local interface     : ejbs.ShoppingCartLocal

   d) 保存
   

==========================================================

4，创建SessionListener 为每个会话初始化shoppingcart

package listeners;

import javax.servlet.http.HttpSessionListener;
import javax.servlet.http.HttpSessionEvent;
import util.User;
import util.ServiceLocator;
import exceptions.ServiceLocatorException;
import javax.ejb.EJBException;
import javax.ejb.CreateException;
import javax.ejb.FinderException;
import ejbs.*;
import delegates.ProductMgmDelegate;
import java.util.Collection;

public class MySessionListener 
                   implements HttpSessionListener {
  public MySessionListener() {
  }

  public void sessionCreated(HttpSessionEvent hse) {

    try{
      ServiceLocator locator =               ServiceLocator.getInstance();
      ShoppingCartLocalHome home =(ShoppingCartLocalHome )
            locator.getEJBLocalHome(                                       "java:comp/env/ejb/cartEJB" );

      ShoppingCartLocal local = home.create();
      hse.getSession().
       setAttribute( ShoppingCartLocal.CART_ATTR, local );
      
    }catch( ServiceLocatorException se ){
      throw new EJBException(se.getMessage() );
    }catch( CreateException ce ){
      throw new EJBException( ce.getMessage() );
    
  }
  public void sessionDestroyed(HttpSessionEvent parm1) {

  }

}

==========================================================

5, 为index.jsp 中 buyProduct.do 创建ActionForm

   file --> new --> web --> ActionForm

   package    : ec_port_web
   ActionForm : BuyProductForm
   --> add from jsp --> index.jsp

   ---> 删除多余的字段，只保留 productId 和 amount -->          finish
=========================================================

package ec_port_web;

import org.apache.struts.action.*;
import javax.servlet.http.*;

public class BuyProductForm extends ActionForm {
  private String amount;
  private String productId;
  public String getAmount() {
    return amount;
  }
  public void setAmount(String amount) {
    this.amount = amount;
  }
  public String getProductId() {
    return productId;
  }
  public void setProductId(String productId) {
    this.productId = productId;
  }
  public ActionErrors validate(ActionMapping ationMapping,
                HttpServletRequest httpServletRequest) {
    return null;
  }
  public void reset(ActionMapping actionMapping, 
            HttpServletRequest httpServletRequest) {
  }
}

=========================================================

6, 修改reset 方法 和 validate 方法

=========================================================

7，为buyProduct.do 创建Action

   file --> new --> web --> Action

   package   : ec_port_web
   Action    : BuyProductAction

   action path   : /buyProduct
   formbean name : buyProductForm
   scope         : session
   validate      : true
   input jsp     : index.jsp

   ---> finish

=========================================================

9, 修改 perform() 方法：

package ec_port_web;

import org.apache.struts.action.*;
import javax.servlet.http.*;
import delegates.ProductMgmDelegate;
import exceptions.*;
import dto.*;
import javax.ejb.CreateException;
import javax.ejb.FinderException;