- _nosay
JDBC实践-连接数据库,并把数据展示出来
2017-12-06 00:24:52
接下来需要把展示页面中,静态数据变成从数据库中取得的动态数据
- 相关的数据库代码为
CREATE DATABASE lession1 CHARACTER SET UTF8;
USE lession1;
CREATE TABLE `lession1`.`user` ( `id` INT(11) NOT NULL AUTO_INCREMENT , `username` VARCHAR(32) NOT NULL , PRIMARY KEY (`id`)) ENGINE = InnoDB;
INSERT INTO `user` (`id`, `username`) VALUES
(NULL, 'user1'),
(NULL, 'user2'),
(NULL, 'user3'),
(NULL, 'user4'),
(NULL, 'user5'),
(NULL, 'user6'),
(NULL, 'user7'),
(NULL, 'user8'),
(NULL, 'user9'),
(NULL, 'user10');
- 这样一个最简单的数据库就建好了,那么现在我们需要设置是jdbc连接
- 建立相应的java bean文件
- 在根目录下建立com.ungly.bean包,在此包中创建User.java文件,具体内容为
package com.ungly.bean;
/**
* 与用户表对应的实体类
*/
public class User {
private String id; //主键
private String username; //用户名
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
}
- 改造ListServlet.java文件,内容变更为
package com.ungly.servlet;
import com.ungly.bean.User;
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 java.io.IOException;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
/**
* 页面初始化控制
*/
@WebServlet(name = "ListServlet",urlPatterns = "/List")
public class ListServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/lession1", "root", "123456");
String sql = "select id,username from user";
PreparedStatement preparedStatement = conn.prepareStatement(sql);
ResultSet resultSet = preparedStatement.executeQuery();
List<User> userList = new ArrayList<>();
while (resultSet.next())
{
User user = new User();
userList.add(user);
user.setId(resultSet.getString("id"));
user.setUsername(resultSet.getString("username"));
}
request.setAttribute("userList",userList);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
request.getRequestDispatcher("/WEB-INF/jsp/front/list.jsp").forward(request,response);
}
}
- 当然还是需要在web/WEB-INF/文件夹下引下lib文件夹,添加mysql的jdbc jar包,这样我们才可以正常的连接数据库,相关下载地址为
下载地址 - 接下来就可以通过JSTL结合el标签来把数据展示出来了.相应的html代码如下:
<%--
Created by IntelliJ IDEA.
User: nosay
Date: 17-12-5
Time: 下午3:31
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<title>Title</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">
<div class="row clearfix">
<div class="col-md-12 column">
<form role="form">
<div class="form-group">
<label for="username">用户名</label><input class="form-control" id="username" type="username" />
</div>
<button type="submit" class="btn btn-default">Submit</button>
</form>
<table class="table">
<thead>
<tr>
<th>编号</th>
<th>用户名</th>
<th>操作</th>
</tr>
</thead>
<tbody>
<c:forEach items="${userList}" var="user" varStatus="status">
<tr>
<td>${status.index +1}</td>
<td>${user.username}</td>
<td>编辑|删除</td>
</tr>
</c:forEach>
</tbody>
</table>
</div>
</div>
</div>
</body>
</html>
运行结果如图