java_web学习(十) 显示mysql中的数据

一.建立数据库

create database animal;

create table animal(

sno int,

name varchar(20),

weight varcahr(20),

color varchar(20),

birth date

);

插入数据

insert into animal values('1','狮子','200kg','黄色','2014-07-30'),('3','老虎','180kg','黄色','2010-02-14'),('2','猴子','20kg','棕色','2003-04-14'),('6','大象','1000kg','黑色','2009-07-12'),('5','长颈鹿','700kg','黄色','2007-07-13');

如图：

 

二.建立一个 web Project项目

在lib文件夹下导入五个包:

项目名为:Animal1

项目里有三个包:entity , action , util

一个jsp文件:An.jsp

ConnManager.java里的代码

 package util;
 
 import java.sql.Connection;
 import java.sql.DriverManager;
 
 public class ConnManager {
 
     //数据库5大参数
     private static final String IP = "127.0.0.1";
     private static final String PORT = "3306";
     private static final String DATABASE_NAME = "zhz";
     private static final String USER_NAME = "root";
     private static final String PASSWORD = "";
     private static final String DRIVER = "org.gjt.mm.mysql.Driver";
 
     public static Connection getConnection() throws Exception {
         String url = "jdbc:mysql://"+IP+":"+PORT+"/"+DATABASE_NAME+"?user="+USER_NAME+"&password="+PASSWORD+"";
         Class.forName(DRIVER);
         Connection conn = DriverManager.getConnection(url);
         return conn;
     }
 
 }

Pig.java里的代码

 package entity;
 
 import java.util.Date;
 
 public class Pig {
     private Integer id=null;
     private String name=null;
     private String weight=null;
     private String color=null;
     private Date birth=null;
     public Integer getId() {
         return id;
     }
     public void setId(Integer id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getWeight() {
         return weight;
     }
     public void setWeight(String weigth) {
         this.weight = weigth;
     }
     public String getColor() {
         return color;
     }
     public void setColor(String color) {
         this.color = color;
     }
     public Date getBirth() {
         return birth;
     }
     public void setBirth(Date birth) {
         this.birth = birth;
     }
 
 }

showPig.java里的代码

 package action;
 
 import java.io.IOException;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.util.ArrayList;
 import java.util.List;
 
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import entity.Pig;
 import util.ConnManager;
 
 @WebServlet("/showPig")
 public class showPig extends HttpServlet {
     private static final long serialVersionUID = 1L;
 
     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         try {
             Connection conn = ConnManager.getConnection();
             String sql = "select * from animal";
             PreparedStatement ps = conn.prepareStatement(sql);
             //建立一个池，用于存放数据
             List<Pig> pigList = new ArrayList<Pig>();
             ResultSet rs = ps.executeQuery();
             while(rs.next()){
                 Integer id = rs.getInt("id");
                 String name = rs.getString("name");
                 String weight = rs.getString("weight");
                 String color = rs.getString("color");
                 java.sql.Date birth= rs.getDate("birth");
                 Pig s = new Pig();
                 s.setId(id);
                 s.setName(name);
                 s.setWeight(weight);
                 s.setColor(color);
                 s.setBirth(birth);
                 pigList.add(s);
             }
             rs.close();
             ps.close();
             conn.close();
             request.setAttribute("pigList", pigList);
             request.getRequestDispatcher("An.jsp").forward(request, response);
 
         } catch (Exception e) {
             System.out.println("发生异常"+e.getMessage());
         }
     }
 
     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 
         doGet(request, response);
     }
 
 }

An.jsp里的代码

 <%@ page language="java" contentType="text/html; charset=UTF-8"
     pageEncoding="UTF-8"%>
 <%@ taglib uri="http://java.sun.com/jsp/jstl/core"  prefix="c"%>
 <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt"  prefix="fmt"%>
 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <title>Insert title here</title>
 </head>
 <body>
 <table border = "2px" width = "80%">
     <tr>
         <td>编号</td>
         <td>名字</td>
         <td>体重</td>
         <td>颜色</td>
         <td>入园日期</td>
     </tr>
     <c:forEach var="L" items="${pigList}">
     <tr>
         <td>${L.id }</td>
         <td>${L.name }</td>
         <td>${L.weight }</td>
         <td>${L.color }</td>
         <td><fmt:formatDate value="${L.birth }" pattern="yyyy-MM-dd"></fmt:formatDate></td>
     </tr>
     </c:forEach>
 </table>
 </body>
 </html>

三.运行结果

运行Servlet,运行结果如图：