购物车的Java代码

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;

public class ShoppingCartManager {
 
 HashMap<String, String> hm=new HashMap<String, String>();
 float totlePrice=0;

 //添加book到购物车
 public void addBook(String bookId,String bookQuantity){
  
  if(hm.containsKey(bookId)){
   int value=Integer.parseInt(hm.get(bookId));
   value+=Integer.parseInt(bookQuantity);
   hm.put(bookId, value+"");
  }else{
   hm.put(bookId, bookQuantity);
  }
 }
 
 //修改数量
 public void updateQuantity(String bookId,String bookQuantity){
  hm.put(bookId, bookQuantity);
 }
 
 //获取购物车的所有信息  并计算总价
 public ArrayList<BookBean> getShoppingCart(){
  ArrayList<BookBean> al=new ArrayList<BookBean>();
  Iterator<String> i=hm.keySet().iterator();
  String ids="";
  BookTableManager btm=new BookTableManager();
  while(i.hasNext()){
   ids=ids+","+i.next();
  }
  al= btm.selectByBookIds(ids);
  
  totlePrice=0; //清空总价，防止无限累计
  for(int j=0;j<al.size();j++){
   BookBean bb=al.get(j);
   totlePrice+=bb.getPrice()*Integer.parseInt(getQuantityById(bb.getBookId()+""));
  }
  
  return al;
 }
 
 //获取总价
 public float getTotlePrice(){
  return totlePrice;
 }
 
 //根据ID获取数量
 public String getQuantityById(String id){
  String quantity=hm.get(id);
  return quantity;
 }
 
 //清空购物车
 public void clear(){
  hm.clear();
 }
 
 //删除购物车中的一本书
 public void deleteById(String id){
  hm.remove(id);
 }

 
}