shopping_cart_doc_1.txt

购物车简单教材

**************shopping_cart项目*****************

1.打开jbuilder.

2.新建一个shopping_cart_project项目。
    选择菜单file->new->project,然后点击[ok]按钮，在出现的界面中输入如下：
     Name:shopping_cart_project
     Directory:.....(自己选择合适的目录)
     然后点击[next],再[next],[finish]。

3.新建web应用
   选择菜单file->new->web->web application，然后点击[ok]按钮,在出现的界面中输入如下：
    Name:cart
    Directory:cart
    JSP/Servlet frameworks:选中struts1.1
    (前提：在tools->configure libraries中配置了struts1.1),然后点击[ok]按钮

4.创建产品表
create table cart(
	id integer primary key,
	name varchar2(32) not null,
	description varchar2(64),
	price float not null
);


insert into cart values(1,'惠普HP PHOTOSART 245','惠普HP PHOTOSART245',2140.00);
insert into cart values(2,'惠普HP OFFICEJET 5510','惠普HP OFFICEJET 5510',2260.00);
insert into cart values(3,'惠普HP PHOTOSART 7960','惠普HP PHOTOSART 7960',3130.00);
insert into cart values(4,'惠普HP PSC 1350','惠普HP PSC 1350',1499.00);
insert into cart values(5,'爱普生 PHOTO 1290 喷墨打印机','爱普生 PHOTO 1290 喷墨打印机',4450.00);
insert into cart values(6,'EPSON 925 喷墨打印机','EPSON 925 喷墨打印机',2855.00);
insert into cart values(7,'惠普HP LJ2300D','惠普HP LJ2300D',6800.00);
insert into cart values(8,'佳能LBP-1210打印机（办公首选）','佳能LBP-1210打印机（办公首选）',2290.00);
insert into cart values(9,'佳能MP730打印一体机','佳能MP730打印一体机',4290.00);
insert into cart values(10,'佳能Canon i560极速打印机','佳能Canon i560极速打印机',1780.00);
insert into cart values(11,'佳能Canon LBP3200商用激光打印机','佳能Canon LBP3200商用激光打印机',2700.00);
insert into cart values(12,'联想LJ2500激光打印机','联想LJ2500激光打印机',2440.00);
insert into cart values(13,'联想激光打印机LJ2800W','联想激光打印机LJ2800W',3590.00);
insert into cart values(14,'联想激光打印机LJ5500','联想激光打印机LJ5500',5440.00);
insert into cart values(15,'联想激光打印机C8000','联想激光打印机C8000',6490.00);
insert into cart values(16,'联想激光打印机LJ7500E','联想激光打印机LJ7500E',7990.00);

5.创建包cart.action，cart.actionform，cart.bean，cart.dao，cart.exception，cart.listener。
   将鼠标放在界面左上方的<Project Source>上点击右键，选择new->package,然后输入相应的包名。

6. 创建业务bean:  在cart.bean包中创建，Product，CartItem，Cart类
    创建Product：将鼠标放在界面左上方的<cart.bean>上点击右键，选择new->class,然后输入如下:
    package:cart.bean
    class name:Product
    然后点击[OK].

 同样的方式创建CartItem和Cart，类的源代码如下：

-------------------------------------------------Product.java------------------------------------------------------------
package cart.bean;

public class Product {
  private Integer id;
  private String name;
  private String description;
  private double price;
  public Product(Integer id, String name,String description ,double price) {

    this.id = id;
    this.name = name;
    this.description = description;
    this.price = price;
  }
  public Integer getId() {
    return id;
  }
  public void setId(Integer id) {
    this.id = id;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public String getDescription() {
    return description;
  }
  public void setDescription(String description) {
    this.description = description;
  }
  public double getPrice() {
    return price;
  }
  public void setPrice(double price) {
    this.price = price;
  }

}

编译源文件
--------------------------------------------------------------------CartItem.java------------------------------------------------------------
package cart.bean;

public class CartItem {
  private Product product;
  private int number;
  private double cost;

  public CartItem(Product product ,int number) {
    this.product = product;
    this.number = number;
    setCost();
  }
  public Product getProduct() {
    return product;
  }
  public void setProduct(Product product) {
    this.product = product;
    setCost();
  }
  public int getNumber() {
    return number;
  }
  public void setNumber(int number) {
    this.number = number;
    setCost();
  }

  private void setCost(){

    if(product == null || number <= 0){
      cost = 0;
      return;
    }

    cost = product.getPrice() * number;
  }

  public double getCost(){

    return cost;
  }

}

编译源文件
---------------------------------------------------------------Cart.java--------------------------------------
package cart.bean;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Collection;

public class Cart {

  private HashMap cartItem;
  private double cost;

  public Cart() {
    cartItem = new HashMap();
    setCost();
  }

  public boolean isEmpty(){

    if(cartItem.size()==0)
      return true;

    return false;
  }

  public int getItemNumber(){

    return cartItem.size();
  }

  public void clear(){

    cartItem.clear();
    setCost();
  }

  public void deleteItemByProductId(Integer productId){
    if(productId == null)
      return ;

    cartItem.remove(productId);
    setCost();
  }

  public void deleteItemsByProductId(Integer[] productId){
    if(productId == null)
      return ;

    for(int i=0;i<productId.length;i++){
      cartItem.remove(productId[i]);
    }

    setCost();
  }

  public void addItem(Product product,int number){

    if(number <= 0)
      return;

    CartItem ci = null;

    if(cartItem.containsKey(product.getId())){
      ci = (CartItem)cartItem.get(product.getId());
      System.out.println("addnumber==>"+number);
      System.out.println("oldNumber===>"+ci.getNumber());
      int new_number = ci.getNumber() + number;
      ci.setNumber(new_number);
      System.out.println("new number===>"+ci.getNumber());
      cartItem.remove(product.getId());
      cartItem.put(product.getId(),ci);
    }else{

      ci = new CartItem(product, number);
      cartItem.put(product.getId(), ci);
    }

    setCost();
  }

  public void modifyNumberByProductId(Integer productId,int number){

    if(!cartItem.containsKey(productId))
      return;

    CartItem ci = (CartItem)cartItem.get(productId);
    ci.setNumber(number);
    cartItem.remove(productId);
    cartItem.put(productId,ci);
    setCost();
  }

  public void setCost(){

    double cost = 0;
    Collection coll = cartItem.values();
    Iterator iter = coll.iterator();
    CartItem ci = null;
    while(iter.hasNext()){
      ci = (CartItem)iter.next();
      cost += ci.getCost();
    }

    this.cost = cost;
  }

  public double getCost(){
    return cost;
  }
  public HashMap getCartItem() {
    return cartItem;
  }
}

编译源文件

7.在包cart.exception下创建DBConnException,源文件如下：

package cart.exception;

public class DBConnException extends Exception{
  public DBConnException() {
    super("数据库异常");
  }

  public DBConnException(String message){
    super(message);
  }

}

编译源文件

8.在包cart.dao下创建ShoppingCartDAO.java,源文件如下：
package cart.dao;

import java.sql.*;
import cart.exception.DBConnException;
import java.util.HashMap;
import cart.bean.Product;

public class ShoppingCartDAO {

  private Connection conn;
  private PreparedStatement pstm;
  private ResultSet rs;

  public ShoppingCartDAO() throws DBConnException{

    try{
      Class.forName("com.pointbase.jdbc.jdbcUniversalDriver");

    }catch(Exception e){
      e.printStackTrace();
      throw new DBConnException();
    }
  }


  public HashMap getAllProduct() throws SQLException{

    HashMap hm = new HashMap();
    String sql = "select id,name,description,price from cart";
    Product product = null;

    try{

      conn = DriverManager.getConnection(
          "jdbc:pointbase:server://localhost:9092/ec_port", "cart", "cart");

      pstm = conn.prepareStatement(sql);
      rs = pstm.executeQuery();
      while (rs.next()) {

        product = new Product(
            new Integer(rs.getInt("id")),
            rs.getString("name"),
            rs.getString("description"),
            rs.getDouble("price"));
        hm.put(new Integer(rs.getInt("id")), product);
      }
      return hm;
    }catch(SQLException e){
      e.printStackTrace();
      throw e;
    }finally{

      if(rs!=null){
        try{
          rs.close();
        }catch(Exception exce){exce.printStackTrace();}
      }
      if(pstm!=null){
        try{
          pstm.close();
        }catch(Exception exce){exce.printStackTrace();}
      }
      if(conn!=null){
        try{
          conn.close();
        }catch(Exception exce){exce.printStackTrace();}
      }
    }
  }
}

编译源文件  

9.创建SCServletContextListener.
   选择file->new->web->servlet，在出现的界面中输入如下：
   package:cart.listener
   class name:SCServletContextListener
   webapp:cart
   在最下面的单选框中选中：listener servlet
   然后点击[next]，在下一个界面中只选中ServletContextListener，然后[next]->[finish]

   该类的源文件如下：
package cart.listener;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import cart.dao.ShoppingCartDAO;
import java.util.HashMap;

public class SCServletContextListener extends HttpServlet implements ServletContextListener {
  //Notification that the web application is ready to process requests
  public void contextInitialized(ServletContextEvent sce) {
    System.out.println("Shopping cart application start.");
    ShoppingCartDAO dao = null;
    HashMap hm = null;
    try{
      dao = new ShoppingCartDAO();
      hm = dao.getAllProduct();
      sce.getServletContext().setAttribute("allProduct",hm);
    }catch(Exception e){
      e.printStackTrace();
    }
  }


  //Notification that the servlet context is about to be shut down
  public void contextDestroyed(ServletContextEvent sce) {

    sce.getServletContext().removeAttribute("allProduct");
    System.out.println("Shopping cart application stop.");
  }
}

10.创建SCSessionListener

   选择file->new->web->servlet，在出现的界面中输入如下：
   package:cart.listener
   class name:SCSessionListener
   webapp:cart
   在最下面的单选框中选中：listener servlet
   然后点击[next]，在下一个界面中只选中HttpSessionListener，然后[next]->[finish]

   该类的源文件如下：
package cart.listener;

import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import cart.bean.Cart;

public class SCSessionListener extends HttpServlet implements HttpSessionListener {
  //Notification that a session was created
  public void sessionCreated(HttpSessionEvent se) {
    System.out.println("a user created.");
    Cart cart = new Cart();
    se.getSession().setAttribute("cart",cart);
  }
  //Notification that a session was invalidated
  public void sessionDestroyed(HttpSessionEvent se) {
    se.getSession().removeAttribute("cart");
    System.out.println("a user destroy.");
  }
}


编译