封裝實體類：PageBean

public class PageBean<T> {
    private int currentPage;//當前頁
    private int currentCount;//頁面顯示條數
    private int totalCount;//總條數
    private int totalPage;//總頁數
    private List<T> list;//當前頁
}

 service分頁實現：

        ProductDao dao = new ProductDao();
        //封裝一個pageBean
 

        PageBean<Product> pageBean = new PageBean<Product>();
        //1.封裝當前頁
        pageBean.setCurrentPage(currentPage);
        //2.封裝每頁顯示條數
        pageBean.setCurrentCount(currentCount);
        //3.封裝總條數
        int totalCount =0;
        try {
            totalCount = dao.getCount(cid);
        } 
 
catch (SQLException e) {
        }
        pageBean.setTotalCount(totalCount);
        //4.封裝總頁數
        int totalPage = (int) Math.ceil(1.0*totalCount/currentCount);
        pageBean.setTotalPage(totalPage);
        //5.封裝當前頁顯示的資料
        int index= (currentPage-1)*currentCount;//起始索引
        List<Product> list =null
 
;
        try {
            list = dao.findProductByPage(cid,index,currentCount);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        pageBean.setList(list); 
        return pageBean;

productInfo  Servlet  開啟商品頁面，寫入cookie

//獲得客戶端攜帶cookie---獲得名字是pids的cookie
　　　　　　
　　　　　String pid = request.getParameter("pid");
        String pids = pid;
        Cookie[] cookies = request.getCookies();
        if(cookies!=null){
            for(Cookie cookie : cookies){
                if("pids".equals(cookie.getName())){
                    pids = cookie.getValue();
                    //1-3-2 本次訪問商品pid是8----->8-1-3-2
                    //1-3-2 本次訪問商品pid是3----->3-1-2
                    //1-3-2 本次訪問商品pid是2----->2-1-3
                    //將pids拆成一個數組
                    String[] split = pids.split("-");//{3,1,2}
                    List<String> asList = Arrays.asList(split);
                    LinkedList<String> list = new LinkedList<String>(asList);
                    //判斷集合中是否存在當前pid
                    if(list.contains(pid)){
                        list.remove(pid);
                        list.addFirst(pid);
                    }else{
                        list.addFirst(pid);
                    }
                    //將[3,1,2]轉成3-1-2字串
                    StringBuffer sb = new StringBuffer();
                    for(int i = 0; i <list.size()&&i<7 ; i++){
                        sb.append(list.get(i));
                        sb.append("-");
                    }
                    //去掉3-1-2-後的-
                    pids = sb.substring(0, sb.length()-1);
                    
                }
            }
            
        }
        Cookie cookie_pids = new Cookie("pids",pids);
        response.addCookie(cookie_pids);
        //轉發前，建立cookie儲存pid
        request.getRequestDispatcher("/product_info.jsp").forward(request, response);

productListBYCid  Servlet  開啟商品列表，讀取cookie

//定義一個記錄歷史商品資訊的集合
        List<Product> historyProductList = new ArrayList<Product>();
        Cookie[] cookies = request.getCookies();
        if(cookies!=null){
            for(Cookie cookie : cookies){
                if("pids".equals(cookie.getName())){
                    String pids = cookie.getValue();
                    String[] split = pids.split("-");
                    for(String pid : split){
                        Product product = service.findProductByPid(pid);
                        historyProductList.add(product);
                    }    
                }
            }
        }
        
        request.setAttribute("historyProductList", historyProductList);
        request.getRequestDispatcher("/product_list.jsp").forward(request, response);