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：