4个版本的java网上书城源码

				package mypack;
				import java.io.Serializable;
				public class ShoppingCartItem implements Serializable{
				    Object item;
				    int quantity;
				
				    public ShoppingCartItem(Object anItem) {
				        item = anItem;
				        quantity = 1;
				    }
				
				    public void incrementQuantity() {
				        quantity++;
				    }
				
				    public void decrementQuantity() {
				        quantity--;
				    }
				
				    public Object getItem() {
				        return item;
				    }
				
				    public int getQuantity() {
				        return quantity;
				    }
				}