小案例：idea用户信息的列表展示详细步骤
1.需求：用户信息的列表展示
····· 2. 1设计：
····· 2.2 技术选型：Servlet+JSP+MySQL+JDBCTempleat+Duird+BeanUtilS+tomcat
2.数据库设计：
create database day17; -- 创建数据库
use day17;
-- 使用数据库
create table user( -- 创建表
id int primary key auto_increment,
name varchar(20) not null,
gender varchar(5),
age int,
address varchar(32),
qq varchar(20),
email varchar(50) );
3.开发：
3.1搭建环境：idea+tomcat
3.2创建项目，导入需要的jar包：
三层架构开发流程图
druid.properties配置文件
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///day17
username=root
password=root
# 初始化连接数量
initialSize=5
# 最大连接数
maxActive=10
# 最大等待时间
maxWait=3000index.jsp-前端代码
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=edge"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>首页</title>
<!-- 1. 导入CSS的全局样式 -->
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- 2. jQuery导入，建议使用1.9以上的版本 -->
<script src="js/jquery-2.1.0.min.js"></script>
<!-- 3. 导入bootstrap的js文件 -->
<script src="js/bootstrap.min.js"></script>
<script type="text/javascript">
</script>
</head>
<body>
<div align="center">
<a
href="${pageContext.request.contextPath}/userListServlet" style="text-decoration:none;font-size:33px">查询所有用户信息
</a>
</div>
</body>
</html>list.jsp-前端代码
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html lang="zh-CN">
<head>
<!-- 指定字符集 -->
<meta charset="utf-8">
<!-- 使用Edge最新的浏览器的渲染方式 -->
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
width: 默认宽度与设备的宽度相同
initial-scale: 初始的缩放比，为1:1 -->
<meta name="viewport" content="width=device-width, initial-scale=1">
<!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
<title>用户信息管理系统</title>
<!-- 1. 导入CSS的全局样式 -->
<link href="css/bootstrap.min.css" rel="stylesheet">
<!-- 2. jQuery导入，建议使用1.9以上的版本 -->
<script src="js/jquery-2.1.0.min.js"></script>
<!-- 3. 导入bootstrap的js文件 -->
<script src="js/bootstrap.min.js"></script>
<style type="text/css">
td, th {
text-align: center;
}
</style>
</head>
<body>
<div class="container">
<h3 style="text-align: center">用户信息列表</h3>
<table border="1" class="table table-bordered table-hover">
<tr class="success">
<th>编号</th>
<th>姓名</th>
<th>性别</th>
<th>年龄</th>
<th>籍贯</th>
<th>QQ</th>
<th>邮箱</th>
<th>操作</th>
</tr>
<c:forEach items="${users}" var="user" varStatus="s">
<tr>
<td>${s.count}</td>
<td>${user.name}</td>
<td>${user.gender}</td>
<td>${user.age}</td>
<td>${user.address}</td>
<td>${user.qq}</td>
<td>${user.email}</td>
<td><a class="btn btn-default btn-sm" href="update.html">修改</a> <a class="btn btn-default btn-sm" href="">删除</a></td>
</tr>
</c:forEach>
<tr>
<td colspan="8" align="center"><a class="btn btn-primary" href="add.html">添加联系人</a></td>
</tr>
</table>
</div>
</body>
</html>
UserDao接口
package cn.itcast.dao;
import cn.itcast.domin.User;
import java.util.List;
/***用户操作的dao*/
public interface UserDao {
public List<User>findAll();
}
UserDaoImpl.class
package cn.itcast.dao.impl;
import cn.itcast.dao.UserDao;
import cn.itcast.domin.User;
import cn.itcast.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import java.util.List;
public class UserDaoImpl implements UserDao {
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
@Override
public List<User> findAll() {
//使用Spring JDBC提供的template操作数据库
//1.定义sql
String sql = "select * from user";
//2.执行sql，返回一个list集合
List<User> users = template.query(sql, new BeanPropertyRowMapper<User>(User.class));
return users;
}
}
User.class 实体类
package cn.itcast.domin;
public class User {
private int id ;
private String name;
private String gender;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
private int age;
private String address;
private String qq;
private String email;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getQq() {
return qq;
}
public void setQq(String qq) {
this.qq = qq;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", gender='" + gender + '\'' +
", age=" + age +
", address='" + address + '\'' +
", qq='" + qq + '\'' +
", email='" + email + '\'' +
'}';
}
}
UserService接口
package cn.itcast.service;
import cn.itcast.domin.User;
import java.util.List;
/**
* 用户管理的业务接口
* **/
public interface UserService{
/**
* @查询用户所有信息
*/
public List<User> findAll();
}
UserServiceImpl.class
import cn.itcast.domin.User;
import cn.itcast.service.UserService;
import java.util.List;
public class UserServiceImpl implements UserService{
//创建UserDao对象
private UserDao dao = new UserDaoImpl();
@Override
public List<User> findAll() {
//调用dao完成查询
return dao.findAll();
}
}JdbcUtils工具类
package cn.itcast.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
/**
* JDBC工具类 使用Durid连接池
*/
public class JDBCUtils {
private static DataSource ds ;
static {
try {
//1.加载配置文件
Properties pro = new Properties();
//使用ClassLoader加载配置文件，获取字节输入流
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(is);
//2.初始化连接池对象
ds = DruidDataSourceFactory.createDataSource(pro);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取连接池对象
*/
public static DataSource getDataSource(){
return ds;
}
/**
* 获取连接Connection对象
*/
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
}
UserListServlet.class
package cn.itcast.web.servlet;
import cn.itcast.domin.User;
import cn.itcast.service.UserService;
import cn.itcast.service.impl.UserServiceImpl;
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.util.List;
/**
* 查询数据库数据并把它显示到页面上
* **/
@WebServlet("/userListServlet")
public class UserListServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.调用UserService完成查询
UserService service = new UserServiceImpl();
List<User> users = service.findAll();
//2.将list存入request域
request.setAttribute("users",users);
//3.转发到list.jsp
request.getRequestDispatcher("/list.jsp").forward(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
项目运行截图
