代码：

1.Product：

1 package domain; 2  3 public class Product { 4      5 /*    `pid` varchar(50) NOT NULL, 6       `pname` varchar(150) DEFAULT NULL, 7       `market_price` double DEFAULT NULL, 8       `shop_price` double DEFAULT NULL, 9       `pimage` varchar(200) DEFAULT NULL,10       `pdate` date DEFAULT NULL,11       `is_hot` int(11) DEFAULT NULL,12       `pdesc` varchar(255) DEFAULT NULL,13       `pflag` int(11) DEFAULT NULL,14       `cid` varchar(50) DEFAULT NULL,15       PRIMARY KEY (`pid`)*/16     17     private String pid;18     private String pname;19     private double market_price;20     private double shop_price;21     private String pimage;22     private String pdate;23     private int is_hot;24     private String pdesc;25     private int pflag;26     private String cid;27     28     public Product(){29         pid="";30         pname="";31         pimage="";32         pdate="";33         pdesc="";34         cid="";35     }36     37     public String getPid() {38         return pid;39     }40     public void setPid(String pid) {41         this.pid = pid;42     }43     public String getPname() {44         return pname;45     }46     public void setPname(String pname) {47         this.pname = pname;48     }49     public double getMarket_price() {50         return market_price;51     }52     public void setMarket_price(double market_price) {53         this.market_price = market_price;54     }55     public double getShop_price() {56         return shop_price;57     }58     public void setShop_price(double shop_price) {59         this.shop_price = shop_price;60     }61     public String getPimage() {62         return pimage;63     }64     public void setPimage(String pimage) {65         this.pimage = pimage;66     }67     public String getPdate() {68         return pdate;69     }70     public void setPdate(String pdate) {71         this.pdate = pdate;72     }73     public int getIs_hot() {74         return is_hot;75     }76     public void setIs_hot(int is_hot) {77         this.is_hot = is_hot;78     }79     public String getPdesc() {80         return pdesc;81     }82     public void setPdesc(String pdesc) {83         this.pdesc = pdesc;84     }85     public int getPflag() {86         return pflag;87     }88     public void setPflag(int pflag) {89         this.pflag = pflag;90     }91     public String getCid() {92         return cid;93     }94     public void setCid(String cid) {95         this.cid = cid;96     }97     98 }

 

2.ProductListD

1 package dao; 2  3 import java.sql.*; 4 import java.util.ArrayList; 5 import java.util.List; 6  7 import domain.Product; 8  9 public class ProductListDao {10 11     public List
     
       getAllProduct(){12         List
      
        productList=new ArrayList
       
        ();//List是接口，不能直接new List13 //        Product product=new Product();//不能只定义一个变量，页面上只显示最后一个商品14         15         try {16             Class.forName("com.mysql.jdbc.Driver");17         } catch (ClassNotFoundException e) {18             e.printStackTrace();19         }20         try {21             Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/web17","root","root");22             PreparedStatement ps=con.prepareStatement("select * from product");23             ResultSet rs=ps.executeQuery();24 //            int i=0;25             while(rs.next()) {26                 Product product=new Product();27                 28                 product.setPid(rs.getString(1));29                 product.setPname(rs.getString(2));30                 product.setMarket_price(rs.getInt(3));31                 product.setShop_price(rs.getInt(4));32                 product.setPimage(rs.getString(5));33                 product.setPdate(rs.getString(6));34                 product.setIs_hot(rs.getInt(7));35                 product.setPdate(rs.getString(8));36                 product.setPflag(rs.getInt(9));37                 product.setCid(rs.getString(10));38                 39 //                System.out.println(product.getPname());40                 productList.add(product);41 //                System.out.println(productList.get(i).getPname());42 //                i++;43             }44             45             rs.close();46             ps.close();47             con.close();48         } catch (SQLException e) {49             e.printStackTrace();50         }51         52         return productList;53     }54     55 }
       
      
     

 

3.ProductListServlet

1 package servlet; 2  3 import java.io.IOException; 4 import java.util.List; 5  6 import javax.servlet.ServletException; 7 import javax.servlet.http.HttpServlet; 8 import javax.servlet.http.HttpServletRequest; 9 import javax.servlet.http.HttpServletResponse;10 11 import dao.ProductListDao;12 import domain.Product;13 14 public class ProductListServlet extends HttpServlet {15 16     protected void doGet(HttpServletRequest request, HttpServletResponse response)17             throws ServletException, IOException {18 19         ProductListDao productListDao=new ProductListDao();20         List
     
       productList=productListDao.getAllProduct();21 //        System.out.println(productList.isEmpty());22         23         request.setAttribute("productList", productList);24         request.getRequestDispatcher("/product_list.jsp").forward(request, response);25         26     }27 28     protected void doPost(HttpServletRequest request, HttpServletResponse response)29             throws ServletException, IOException {30         doGet(request, response);31     }32 33 }
     

 

4.product_list.jsp

1 <%@ page language="java" contentType="text/html; charset=UTF-8"  2     pageEncoding="UTF-8"%>  3 <%@ page import="java.util.*"%>  4 <%@ page import="domain.*"%>  5   6   7   8 
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 43  44         <% 45             List
      
        productList = (List
       
        ) request.getAttribute("productList"); 46  47             if (productList != null) { 48                 for (Product product : productList) { 49  50                     out.write("
        
         "); 51                     out.write("
          "); 52                     out.write(""); 53                     out.write("
         
"); 54                     out.write(""+product.getPname()+""); 55                     out.write("
"); 56                     out.write("
         
"); 57                     out.write("商城价：¥"+product.getShop_price()+""); 58                     out.write("
"); 59                     out.write("
        
"); 60  61                 } 62             } 63         %> 64  65     
       
      
     
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结果：

 

 

注意：

加入List内的元素只保存了地址，而不是复制元素。将元素加入List后，修改该元素值，会影响到List内的元素值。所以每次放入一个新元素都需要new一个新地址。否则结果只有最后一个元素值，前面的元素值都被覆盖了。