怎么实现让两个list相同的元素在某个list中数量加1，不同的元素也都存到这个list中？

Question

我的这些代码是错的，实现不了？该怎么改？各位大神帮帮忙，纠结好几天了！
List cartlist2=(List)session.getAttribute("cartlist2");
List list=new ArrayList();
for(int i=0;i<cartlist.size();i++){
goods=(Goods)cartlist.get(i);
for(int j=0;j<cartlist2.size();j++){

goods2=(Goods)cartlist2.get(j);
if(goods.getGid().equals(goods2.getGid())){

int gnumber=goods2.getGnumber();
goods2.setGnumber(gnumber+1);

list.add(goods2);
cartlist2.remove(goods2);
break;
}else{

String gid=goods.getGid();
String gname=goods.getGname();
int gprice=goods.getGprice();
String gpress=goods.getGpress();
int gpostage=goods.getGpostage();
int gnumber=1;
goods3=new Goods(gid,gname,gprice,gpress,gpostage,gnumber);
list.add(goods3);
}

                }
            }
            for(int k=0;k<list.size();k++){
                goods3=(Goods)list.get(k);
                cartlist2.add(goods3);
            }
            session.setAttribute("cartlist2",cartlist2);  
            //response.sendRedirect("shoppingcart.jsp");
            request.getRequestDispatcher("shoppingcart.jsp").forward(request, response);  

Answer 1

用一个boolean 标志标识for循环就Ok了