Java struts2编程

用struts2实现一个简单的购物车，将物品放到session中，具体实现方法 步骤，要详细

ShopCart.java:
import java.util.Collection;
import java.util.Hashtable;
import java.util.Iterator;
import com.ascent.po.Product;

public class ShopCart {
private Hashtable<Integer, CarItem> car = null;
private Collection<CarItem> carItems = null;
public ShopCart() {
car = new Hashtable<Integer, CarItem>();
carItems = car.values();// 初始化生成购物车项
}
public Hashtable<Integer, CarItem> getCar() {
return car;
}
public void setCar(Hashtable<Integer, CarItem> car) {
this.car = car;
}
public Collection<CarItem> getCarItems() {
return carItems;
}
public void setCarItems(Collection<CarItem> carItems) {
this.carItems = carItems;
}

public void addProduct(Product product) {
if (!car.containsKey(product.getPid())) {// 第一次购买，当car中没有的时候
// ，准备key和value的值
// 往map集合中放，然后生成了购物车项carItems
CarItem item = new CarItem(product);
car.put(product.getPid(), item);
carItems = car.values();
} else { // 第二次购买
CarItem item = car.get(product.getPid());
item.increase();
}
}

public void updateProductNumber(Integer pid, Integer number) {
CarItem item = car.get(pid);
item.setNumber(number);
carItems = car.values();
}

public void deletProduct(Integer pid) {
if (car.containsKey(pid)) {
car.remove(pid);
carItems = car.values();
}
}

public double getTotalPrice() {
Iterator<CarItem> it = carItems.iterator();
double total = 0.0;
while (it.hasNext()) {
CarItem carItem = it.next();
total += carItem.getCarItemPrice();
}
return total;
}
}
CarItem.java
import com.ascent.po.Product;
public class CarItem {
private  Product product;
private int number;
public CarItem(Product product){
this.product=product;
this.number=1;
}
public Product getProduct() {
return product;
}
public void setProduct(Product product) {
this.product = product;
}
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}

public void increase(){
number++;
}

public double getCarItemPrice(){
return  new Double(product.getPrice1()).doubleValue()*number;
}
}
以上这两个类是 实现购物车功能的工具类，以前就是用这两个类开发过购物车的
以下是 action类  这个是问题关键所在

@SuppressWarnings("unchecked")
public String addProduct() {
    ShoppingCart car = (ShoppingCart) ActionContext.getContext().getSession().get("ShoppingCar");
System.out.println("-----------------"+car);
if (car == null) {
car = new ShoppingCart();
ActionContext.getContext().getSession().put("ShoppingCar", car);
}
ProductDao productdao = new ProductDao();
Product product = productdao.getProductByPid(pid);
System.out.println("-----------------"+product);
car.addProduct(product);
return SUCCESS;
}

public String deletProduct() {
ShoppingCart car = (ShoppingCart) ActionContext.getContext()
.getSession().get("ShoppingCar");
car.deletProduct(pid);
return SUCCESS;
}

public String updateProduct() {
ShoppingCart car = (ShoppingCart) ActionContext.getContext().getSession().get("ShoppingCar");
int n = new Integer(number);
car.updateProductNumber(pid, n);
return SUCCESS;
}

public String getToalePrices() {
ShoppingCart car = (ShoppingCart) ActionContext.getContext()
.getSession().get("ShoppingCar");
totalPrice = car.getTotalPrice();
return SUCCESS;
}

session中存一个List，list里面可以装物品对象，也可以装主见Id,添加一个物品，就在list.add一个，删除就list.remove就行了

用JSP 就能了 还用那么复杂？