1.实验目的

通过设计并实现一个简单全栈系统的方式提升对Web相关技术的理解、掌握及应用。

2.实验任务

本次实验任务为实现一个登录页面。具体要求如下：

实现前端页面的基本布局。要求：
布局类似于学校门户http://my.csu.edu.cn/login/index.jsp
顶部需有LOGO栏目；
左侧提供轮播图；
提供账号密码登录方式；
提供手机号码（邮箱）+验证码登录方式；
登录成功后跳到显示“登录成功”四字的页面（简单设计）；
提供忘记密码和修改密码功能；
提供用户的增删改查。
完成前后端数据交互
数据操作要求：
数据统一存储在后端数据库中；
账号密码登录方式需进行验证，验证通过方能登录；
邮箱验证码需调用第三方短信接口发送验证码并进行验证；
后端实现技术不限、数据库系统不限。

3.实验展示

3.1邮箱登录

登录界面：

输入邮箱并点击“点击获取验证码”

输入验证码并点击“登录”。

3.2账号密码登录

3.3修改密码

点击修改密码，进入密码修改界面

输入旧密码和新密码

点击保存：

点击上面提示框中的"确定"，返回登录界面

从数据库中可以看到，密码已经修改成功了：

3.4 忘记密码

点击忘记密码：

进入忘记密码界面：

输入邮箱，并点击获取验证码

输入新密码

点击“设置新密码”

点击“确定”，返回登录界面

3.5管理员登录

输入的账号为"admin"

进入管理员界面

3.5.1增加用户

点击”ADD User“：

进入添加用户界面：

输入用户信息：

点击“确定”返回管理员界面，可以看到新增的用户：

3.5.2删除用户

直接点击相应用户后面的“DELETE”

点击“确定”，返回管理员界面，可以看到“李五”用户已经被删除

3.5.3修改用户信息

点击相应用户后面的EDIT：

点击“李四”后面的“EDIT”按钮，进入李四的用户信息编辑界面

修改李四的名字为“李四四”，点击submit按钮

点击弹窗的“确定”按钮，返回管理员界面，可以看到李四的名字已经改为李四四

3.5.4查找用户

点击"Search User"

进入查找用户界面

按照userID查找

查找userID中所有带“2”的用户

点击“search”，查看查找结果

按照userName查找

查找所有用户名字中带“四”的

查找结果

按照userID和userName查找

查找所有userID带2且userName带“四”的用户

查找所有用户

若在输入时什么也不输入，则是查找所有用户

4.实验过程

4.1在mySql里创建数据库及表格

创建webhomeword数据库并在其中创建users表格

表的结构如下

先插入一些数据

4.2搭建 WEB 应用框架;

4.2.1.创建一个maven web项目

4.3.2.修改配置

4.2.3.在main里创建java和recourse目录

4.2.4.导入项目中会遇到的jar包

jsp,Servlet,mysql,jstl,taglibs

<dependency>
    <groupId>javax.servlet.jsp</groupId>
    <artifactId>javax.servlet.jsp-api</artifactId>
    <version>2.3.3</version>
</dependency>

<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>servlet-api</artifactId>
  <version>2.5</version>
</dependency>

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.27</version>
</dependency>

<dependency>
  <groupId>javax.servlet.jsp.jstl</groupId>
  <artifactId>jstl-api</artifactId>
  <version>1.2</version>
</dependency>

<dependency>
    <groupId>taglibs</groupId>
    <artifactId>standard</artifactId>
    <version>1.1.2</version>
</dependency>

4.2.5.更改web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
</web-app>

4.2.6.配置Tomcat

4.2.7导入项目中会遇到dependency

<dependencies>
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.11</version>
    <scope>test</scope>
  </dependency>


  <dependency>
    <groupId>javax.servlet.jsp</groupId>
    <artifactId>javax.servlet.jsp-api</artifactId>
    <version>2.3.3</version>
  </dependency>

  <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>2.5</version>
  </dependency>

  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.27</version>
  </dependency>

  <dependency>
    <groupId>javax.servlet.jsp.jstl</groupId>
    <artifactId>jstl-api</artifactId>
    <version>1.2</version>
  </dependency>

  <dependency>
    <groupId>taglibs</groupId>
    <artifactId>standard</artifactId>
    <version>1.1.2</version>
  </dependency>

  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
  </dependency>

4.3 前端页面设计

前端目录结构如下：

4.3.1登录界面 login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>

<html>
<head>
    <meta charset="utf-8">
    <title>login</title>
    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath }/css/pageChange.css" />
    <script src="${pageContext.request.contextPath }/js/pageChange.js">

    </script>

</head>

<body  style=" background-repeat:repeat ;background-size:auto auto;
background-attachment: fixed; background: url('${pageContext.request.contextPath }/images/bg2.jpg');">

<%
    Object message = request.getAttribute("message");
    if(message!=null && !"".equals(message)){
%>
<script type="text/javascript">
    alert("<%=request.getAttribute("message")%>");
</script>
<%} %>


<div class="head">
    <img src="${pageContext.request.contextPath }/images/head.png" alt="">
</div>

<div class="control">

    <div class="item">
        <div class="active" style="float: left;">邮箱登录</div>
        <div>账号密码登录</div>
    </div>

    <div class="content">

        <div style="display: block;">
            <form action="${pageContext.request.contextPath}/getIdentifyCode.do" method="post">
                <p>邮箱</p>
                <input type="text" placeholder="email" name="email" value="${email}">
                <input type="submit" class='verifyCode' value="点击获取验证码">
            </form>
            <form  method = "post" action="${pageContext.request.contextPath}/emailLogin.do">
                <p>验证码</p>
                <input type="text" placeholder="code" name="inputIdentifyCode">
                <br />
                <input type="submit" value="登录">
            </form>
        </div>

        <div>
            <form action="${pageContext.request.contextPath}/login.do" method="post">
                <p>账号:${error}</p><input type="text" name="userID" placeholder = "userID">
                <p>密码:</p><input type="password" name="password" placeholder="password">
                <input type="submit" value="登录"><input type="reset" value="重置">
            </form>
            <a href="${pageContext.request.contextPath}/jsp/forgetPwd.jsp">忘记密码</a>
        </div>
    </div>
</div>

<!--轮播图 https://blog.csdn.net/weixin_43751022/article/details/84330552 -->
<div id="slideBox" onmouseover="stop()" onmouseout="start()">
    <div id="red" class="slide"><img src="${pageContext.request.contextPath }/images/slide1.jpg" alt="slide1" width="500" height="500"></div>
    <div id="green" class="slide"><img src="${pageContext.request.contextPath }/images/slide2.jpg" alt="slide2" width="500" height="500"></div>
    <div id="blue" class="slide"><img src="${pageContext.request.contextPath }/images/slide3.jpg" alt="slide3" width="500" height="500"></div>
</div>

</body>
</html>

4.3.2登录成功界面 successLogin.jsp

<%--
  Created by IntelliJ IDEA.
  User: lenovo
  Date: 2021/11/22
  Time: 9:06
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>

<head>
    <title>successLogin</title>

    <style>
        .content {
            position: relative;
            left: 40%;
            top: 20%;
        }

        .pwdmodify {
            width: 100px;
            height: 40px;

            position: relative;
            left: 6%;
            top: 50px;
        }

        #modifyBtn {
            width: 100px;
            height: 50px;
            background-color: rgb(223, 52, 52);
        }

        h1 {
            color: blanchedalmond;
        }
    </style>
</head>


<body  style=" background-size:auto 100%;background-attachment: fixed; background: url('${pageContext.request.contextPath }/images/background4.jpg');">

<div class="content">
    <h1>用户：${userSession.userName}</h1>
    <h1>登陆成功</h1>

    <div class="pwdmodify">
        <a href="/smbms_war/jsp/changePwd.jsp"><button id="modifyBtn">修改密码</button></a>
    </div>

</div>

</body>

</html>

4.3.3修改密码界面 changePwd.jsp

<%--
  Created by IntelliJ IDEA.
  User: lenovo
  Date: 2021/11/24
  Time: 16:29
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>

<head>
    <title>修改密码</title>

    <style>
        .location {
            width: 350px;
            height: 150px;
            position: relative;
            top: 10%;
            left: 40%;
            /* left: 600; */
            /* border: #e7c9a7 10px solid; */

        }

        strong {
            color: hsla(0, 0%, 99%, 0.966);
            font-size: x-large;
        }

        .providerAdd {
            width: 150px;
            height: 400px;
            position: relative;
            top: 50px;
            /* left: 700; */
            left: 45%;
            /* border: #e7c9a7 10px solid; */
        }

        h2 {
            color: hsla(0, 0%, 99%, 0.966);
        }

        #save {
            position: relative;
            width: 55%;

        }
    </style>

</head>

<body  style=" background-repeat:repeat ;background-size:50%;
background-attachment: fixed; background: url('${pageContext.request.contextPath }/images/background2.jpg');">

<%
    Object message = request.getAttribute("message");
    if(message!=null && !"".equals(message)){
%>
<script type="text/javascript">
    alert("<%=request.getAttribute("message")%>");
</script>
<%} %>

<div class="location">
    <h2>${userSession.userID}</h2>
    <strong>您现在的位置是：</strong>
    <strong>密码修改界面</strong>
</div>

<div class="providerAdd">
    <form action="${pageContext.request.contextPath}/changePwd.do" id="userFrom" name="userForm" method="post">
        <input type="hidden" name="method" value="savepwd">
        <div class="info">
        </div>
        <div>
            <label for="oldPassword">
                <h2>旧密码：</h2>
            </label>
            <input type="password" name="oldpassword" id="oldPassword" value="">
        </div>

        <div>
            <label for="newPassword">
                <h2>新密码：</h2>
            </label>
            <input type="password" name="newpassword" id="newPassword" value="">
        </div>

        <div>
            <label for="rnewPassword">
                <h2>确认新密码：</h2>
            </label>
            <input type="password" name="rnewpassword" id="rnewPassword" value="">
        </div>

        <div class="providerAddBtn">
            <h2></h2>
            <input type="submit" name="save" id="save" value="保存" class="input-button">
        </div>
    </form>
</div>
</body>

</html>

4.3.5忘记密码界面 forgetPwd.jsp

<%--
  Created by IntelliJ IDEA.
  User: lenovo
  Date: 2021/11/26
  Time: 22:29
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html lang="en">

<head>
  <title>Document</title>
  <!-- <%-- <link rel="stylesheet" type="text/css" href="../css/pageChange.css" />--%> -->
  <style>
    .my-content {
      width: 280px;
      background: rgba(255, 255, 255, 0.1);
      position: absolute;
      left: 40%;
      top: 20%;
      border: 1px solid #ce3e3e;
    }

    p {
      color: white;
    }

    h2 {
      color: white;
    }
  </style>
</head>

<body style=" background-repeat:repeat ;background-size:100% 100%;
        background-attachment: fixed; background: url('${pageContext.request.contextPath }/images/bg3.jpg');">

<%
  Object message = request.getAttribute("forgetPwd");
  if(message!=null && !"".equals(message)){
%>
<script type="text/javascript">
  alert("<%=request.getAttribute("forgetPwd")%>");
</script>
<%} %>

<div class="my-content" style="display: block;">
  <form action="${pageContext.request.contextPath}/getIdentifyCodeServlet2.do" method="post">
    <p>用户名</p>
    <input type="text" placeholder="userID" name="userID" value="${userID}">
    <p>邮箱</p>
    <input type="text" placeholder="email" name="email2" value=${email2}>
    <input type="submit" class='verifyCode' value="点击获取验证码">
  </form>
  <form action="${pageContext.request.contextPath}/forgetPwd.do" method="post">
    <p>验证码</p>
    <input type="text" placeholder="identifyCode" name="identifyCode">
    <p>新密码</p>
    <input type="password" placeholder="newPassword" name="newPassword">
    <input type="submit" class='submitChangePwd' value="设置新密码">
  </form>

</div>
</div>
</body>

</html>

4.3.6管理员界面 CURDindex.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
  Created by IntelliJ IDEA.
  User: ZHENGZHIQIANG
  Date: 2019/3/2
  Time: 9:59
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Show</title>
    <style type="text/css">
        table {
            border: 1px solid pink;
            margin: 0 auto;
        td{
            width: 150px;
            border: 1px solid pink;
            text-align: center;
        }
    </style>
</head>
<body>

<h1>欢迎管理员登录</h1>
<%
    Object message = request.getAttribute("message");
    Object grade_list = request.getAttribute("grade_list");
    if(message!=null && !"".equals(message)){

%>
<script type="text/javascript">
    alert("<%=request.getAttribute("message")%>");
</script>
<%} %>

<table>
    <tr>
        <td>userID</td>
        <td>userName</td>
        <td>password</td>
        <td>email</td>
    </tr>
    <c:forEach items="${userList}" var="user">
        <tr>
            <td>${user.userID}</td>
            <td>${user.userName}</td>
            <td>${user.password}</td>
            <td>${user.email}</td>
            <td><a href="DeleteServlet?userID=${user.userID}">DELETE</a>-----<a href="UpdateServlet?userID=${user.userID}">EDIT</a> </td>
        </tr>

    </c:forEach>
    <tr>
        <td colspan="2" style="text-align: left"><a href="${pageContext.request.contextPath }/jsp/add.jsp">ADD User</a> </td>
        <td colspan="2" style="text-align: right"><a href="${pageContext.request.contextPath }/jsp/search.jsp">Search User</a> </td>
        <td colspan="2" style="text-align: right"><a href="${pageContext.request.contextPath }/jsp/login.jsp">HOME</a> </td>
    </tr>
</table>

</body>
</html>

4.3.7添加用户界面 add.jsp

<%--
  Created by IntelliJ IDEA.
  User: ZHENGZHIQIANG
  Date: 2019/3/2
  Time: 16:14
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
  <title>ADD</title>
</head>
<body>
<div align="center">
<form action="${pageContext.request.contextPath}/AddServlet" method="post">
  <table border="1" >
    <tr>
      <td colspan="2"><h1>Add User</h1></td>
    </tr>
    <tr>
      <td>Add userID </td>
      <td><input type="text" name="userID"/></td>
    </tr>
    <tr>
      <td>Add userName </td>
      <td><input type="text" name="userName"/></td>
    </tr>
    <tr>
      <td>Add password </td>
      <td><input type="password" name="password"/></td>
    </tr>
    <tr>
      <td>Add email</td>
      <td><input type="text" name="email"/></td>

    </tr>
    <tr>
      <td colspan="2">
        <input type="submit" value="submit">
        <input type="reset" value="Flush">
      </td>
    </tr>
  </table>
</form>
</div>
</body>
</html>

4.3.8修改用户信息界面 update.jsp

<%--
  Created by IntelliJ IDEA.
  User: ZHENGZHIQIANG
  Date: 2019/3/2
  Time: 16:34
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
  <title>Edit</title>
</head>
<body>
<div align="center">
<form action="${pageContext.request.contextPath}/UpdateServlet" method="post" style="align-items: center">
  <table border="1" >
    <tr>
      <td colspan="2"><h1>Edit User</h1></td>
    </tr>
    <tr>
      <td>userID</td>
      <td><input type="text" name="userID" value="${user.userID}"/></td>
    </tr>
    <tr>
      <td>userName</td>
      <td><input type="text" name="userName" value="${user.userName}" /></td>
    </tr>
    <tr>
      <td>password</td>
      <td><input type="password" name="password" value="${user.password}" /></td>
    </tr>
    <tr>
      <td>email</td>
      <td><input type="text" name="email" value="${user.email}" /></td>
    </tr>
    <tr>
      <td colspan="2">
        <input type="submit" value="Submit"/>
        <input type="button" value="Back" onclick="history.go(-1)"/>
      </td>
    </tr>
  </table>
</div>
</form>
</body>
</html>

4.3.9 查找用户界面 search.jsp

<%--
  Created by IntelliJ IDEA.
  User: lenovo
  Date: 2021/12/3
  Time: 14:01
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>

<head>
    <title>Title</title>
</head>

<body>
<div align="center">
<form action="${pageContext.request.contextPath}/SearchServlet" method="post" style="align-items: center">
    <table border="1">
        <tr>
            <td colspan="2">
                <h1>Search User</h1>
            </td>
        </tr>
        <tr>
            <td>userID:</td>
            <td><input name = "userID" type="text"></td>
        </tr>
        <tr>
            <td>userName:</td>
            <td><input name="userName" type="text"></td>
        </tr>
        <tr>
            <td colspan="2">
                <input type="submit" value="search">
                <input type="reset" value="flush">
            </td>
        </tr>
    </table>

</form>
</div>
</body>

</html>

4.3.10 界面样式pageChange.css

*{
    margin:0;
    padding: 0;
}
body{
    background: #f3f3f3;
}

.control{
    width: 340px;
    background: white;
    /*background: rgba(255, 255, 255, 1);*/
    position: absolute;
    top: 60%;
    left: 75%;
    transform: translate(-50%,-50%);
    border-radius: 5px;

}

.item{
    width: 340px;
    height: 60px;
    background: #eeeeee;
}

.item div{
    width: 170px;
    height: 60px;
    display: inline-block;
    color: black;
    font-size: 18px;
    text-align: center;
    line-height: 60px;
    cursor:pointer;
}

.content div{
    margin: 20px 30px;
    display: none;
    text-align: left;
    margin-bottom: 6px;
    font-size: 15px;
}

p{
    color: #4a4a4a;
    margin-top:30px;
    margin-bottom: 6px;
    font-size: 15px;
}

.content input[type = "text"], .content input[type="password"]{
    width: 100%;
    height: 40px;
    border-radius: 3px;
    border:1px solid #adadad;
    padding:0 10px;
    box-sizing: border-box;
}

.content input[type="submit"]
{
    margin-top :40px;
    width: 100%;
    height: 40px;
    border-radius: 5px;
    color:white;
    border:1px solid #adadad;
    background: #00dd60;
    cursor: pointer;
    letter-spacing: 4px;
    margin-bottom: 40px;

}


.active{
    background: white;
}

.item div:hover{
    background: #f6f6f6;
}

#slideBox{
    width:500px;
    height:500px;
    border:1px solid black;
    position:absolute;
    top: 160px;
    left: 200px;
    overflow:hidden;
}
.slide{
    width:500px;
    height:500px;
    position:absolute;
}

#red{
    /*background-color:red;*/
    width:500px;
}

#green{
    /*background-color:green;*/
    width:500px;
}
#blue{
    /*background-color:blue;*/
    width:500px;
}

4.3.11 轮播图 pageChange.js

window.onload = function () {
    var arr = document.getElementsByClassName("slide");
    for (var i = 0; i < arr.length; i++) {
        arr[i].style.left = i * 500 + "px";
    }

    var item = document.getElementsByClassName("item");
    var it = item[0].getElementsByTagName("div");
    var content = document.getElementsByClassName("content");
    var con = content[0].getElementsByTagName("div");

    for (let i = 0; i < it.length; i++) {
        it[i].onclick = function () {
            for (let j = 0; j < it.length; j++) {
                it[j].className = '';
                con[j].style.display = "none";
            }
            this.className = "active";
            it[i].index = i;
            con[i].style.display = "block"
        }
    }
}

function LeftMove() {
    var arr = document.getElementsByClassName("slide");//获取三个子div
    originLeft = document.getElementById("slide");

    for (var i = 0; i < arr.length; i++) {
        var left = parseFloat(arr[i].style.left);
        left -= 2;
        var width = 500;//图片的宽度
        var pos_left = document.getElementById("slideBox").offsetLeft;
        var pos_top = document.getElementById("slideBox").offsetTop;

        // console.log(pos_left);
        // console.log(pos_top);

        if (left <= originLeft - width) {
            left = (arr.length - 1) * width;//当图片完全走出显示框，拼接到末尾
            clearInterval(moveId);
        }
        arr[i].style.left = left + "px";
    }
}

function divInterval() {
    moveId = setInterval(LeftMove, 10);//设置一个10毫秒定时器
}


timeId = setInterval(divInterval, 5000);

function stop() {
    clearInterval(timeId);
}
function start() {
    clearInterval(timeId);
    timeId = setInterval(divInterval, 5000);
}

//页面失去焦点停止
onblur = function () {
    stop();
}
//页面获取焦点时开始
onfocus = function () {
    start();
}

4.4 Dao模块

4.4.1 操作数据库的最基本模块：BaseDao.class

package com.qi.dao;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

//操作数据库的公共类
public class BaseDao {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;

    //静态代码块，类加载时就初始化
    static{
        Properties properties = new Properties();
        //通过类加载器读取对应的资源
        InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");

        try {
            properties.load(is);
        } catch (IOException e) {
            e.printStackTrace();
        }

        driver = properties.getProperty("driver");
        url = properties.getProperty("url");
        username = properties.getProperty("username");
        password = properties.getProperty("password");
    }

    //获取数据库的连接
    public static Connection getConnection(){
        Connection connection = null;
        try {
            Class.forName(driver);
            connection = DriverManager.getConnection(url, username, password);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return connection;
    }

    //编写查询公共类
    public static ResultSet execute(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet,String sql,Object[] params) throws SQLException {
        //预编译sql,在后面直接执行就可以了
        preparedStatement = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++) {
            preparedStatement.setObject(i+1,params[i]);
        }
//        System.out.println(sql);
        resultSet = preparedStatement.executeQuery();
        return resultSet;
    }

    //编写增删改公共方法
    public static int execute(Connection connection,PreparedStatement preparedStatement,String sql,Object[] params) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++) {
            preparedStatement.setObject(i+1,params[i]);
        }
        int updateRows = preparedStatement.executeUpdate();
        return updateRows;
    }

    //关闭资源
    public static boolean closeRecourse(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet) {
        boolean flag = true;
        if(resultSet!= null) {
            try {
                resultSet.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
                flag = false;
            }
        }

        if(preparedStatement != null) {
            try {
                preparedStatement.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
                flag = false;
            }
        }
        if(connection!= null)
        {
            try {
                connection.close();
                connection = null;
            } catch (SQLException throwables) {
                flag = false;
                throwables.printStackTrace();
            }
        }
        return flag;
    }
}

4.4.2 用户操作数据库的基本功能接口：UserDao.class

package com.qi.dao.user;

import com.qi.pojo.User;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;

public interface UserDao {

    //得到登录的用户
    public User getLoginUser(Connection connection, String account) throws SQLException;

    //通过邮箱得到用户
    public User getLoginUserByEmail(Connection connection,String email) throws SQLException;

    //修改当前用户密码
    public int updatePwd(Connection connection,String userID,String password) throws SQLException;

    //根据userID查询旧密码
    public String selectPassword(Connection connection,String userID) throws SQLException;

    //添加用户
    public boolean add(Connection connection,String userID,  String userName, String password, String email) throws SQLException;

    //获取所有用户的列表
    public ArrayList<User> selectAll(Connection connection) throws SQLException;

    //更新用户信息
    public boolean update(Connection connection,String userID, String userName,String password,String email) throws SQLException;

    //删除用户
    public boolean delete(Connection connection,String userID) throws SQLException;

    //根据用户ID和Name获取用户
    public ArrayList<User> selectByIDName(Connection connection,String userID,String userName) throws SQLException;


}

4.4.3 实现UserDao接口：UserDaoImpl.class

package com.qi.dao.user;

import com.mysql.cj.util.StringUtils;
import com.qi.dao.BaseDao;
import com.qi.pojo.User;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

public class UserDaoImpl implements UserDao{

    public User getLoginUser(Connection connection, String userID) throws SQLException {
        PreparedStatement pstm = null;
        ResultSet rs = null;
        User user = null;
        //判断数据库是否连接成功
        if(connection!=null)
        {
            String sql = "select * from users where userID=?";
            Object[] params = {userID};
            //连接成功则执行sql语句并返回结果集
                rs = BaseDao.execute(connection,pstm,rs,sql,params);
                if(rs.next()){
                    user = new User();
                    user.setUserID(rs.getString("userID"));
                    user.setUserName(rs.getString("userName"));
                    user.setPassword(rs.getString("password"));
                    user.setEmail(rs.getString("email"));
                }
                BaseDao.closeRecourse(null,pstm,rs);
        }
        return user;
    }

    public User getLoginUserByEmail(Connection connection,String email) throws SQLException {
        PreparedStatement pstm = null;
        ResultSet rs = null;
        User user = null;
        //判断数据库是否连接成功
        if(connection!=null)
        {
            String sql = "select * from users where email=?";
            Object[] params = {email};
            //连接成功则执行sql语句并返回结果集
            rs = BaseDao.execute(connection,pstm,rs,sql,params);
            if(rs.next()){
                user = new User();
                user.setUserID(rs.getString("userID"));
                user.setPassword(rs.getString("password"));
                user.setEmail(rs.getString("email"));
                user.setUserName(rs.getString("userName"));
            }
            BaseDao.closeRecourse(null,pstm,rs);
        }
        return user;
    }
    //修改当前用户的密码
    public int updatePwd(Connection connection, String userID, String password) throws SQLException {

        PreparedStatement pstm = null;
        int execute = 0;
        if(connection!=null)
        {
            String sql = "update users set password = ? where userID = ?";
            Object params[] = {password,userID};
            execute = BaseDao.execute(connection,pstm,sql,params);
            BaseDao.closeRecourse(null,pstm,null);
        }
        return execute;

    }

    @Override
    public String selectPassword(Connection connection, String userID) throws SQLException {
        PreparedStatement pstm = null;
        String oldPassword = null;
        ResultSet rs = null;
        if(connection!=null)
        {
            String sql = "select * from users where userID = ?";
            Object params[] = {userID};
            rs = BaseDao.execute(connection,pstm,rs,sql,params);
            if(rs.next()){
                oldPassword = rs.getString("password");
            }

             BaseDao.closeRecourse(null,pstm,rs);
        }
        return oldPassword;
    }



    @Override
    public boolean add(Connection connection, String userID, String userName, String password, String email) throws SQLException {
        PreparedStatement pstm = null;
        int rs ;
        boolean flag = false;
        if(connection!=null){
            String sql = "insert into users values (?,?,?,?)";
            String[] params = {userID,userName,password,email};
            //Connection connection,PreparedStatement preparedStatement,String sql,Object[] params
            rs = BaseDao.execute(connection, pstm,sql, params);
            if(rs != 0){
                flag = true;
            }
            BaseDao.closeRecourse(connection,null,null);
        }
        return flag;
    }



    @Override
    public ArrayList<User> selectAll(Connection connection) throws SQLException {
        PreparedStatement pstm = null;
        ResultSet rs = null;
        ArrayList<User> userList = new ArrayList<>();
        if(connection!=null){
            String sql = "select * from users";
            String[] params = {};
            rs = BaseDao.execute(connection, pstm, rs, sql, params);
            while(rs.next()){
                User _user = new User();
                _user.setUserID(rs.getString("userID"));
                _user.setPassword(rs.getString("password"));
                _user.setEmail(rs.getString("email"));
                _user.setUserName(rs.getString("userName"));
                userList.add(_user);
            }
            BaseDao.closeRecourse(connection,null,rs);
        }
        return userList;
    }
    @Override
    public ArrayList<User> selectByIDName(Connection connection, String userID,String userName) throws SQLException {
        PreparedStatement pstm = null;
        ResultSet rs = null;
        ArrayList<User> userList = new ArrayList<>();
        String sql = null;
        String[] params = null;
        if(connection!=null){
            if(! StringUtils.isNullOrEmpty(userID) && StringUtils.isNullOrEmpty(userName))
            {
                sql = "select * from users where userID like ?";
                params = new String[]{"%"+userID+"%"};
            }else if(StringUtils.isNullOrEmpty(userID) && !StringUtils.isNullOrEmpty(userName))
            {
                sql = "select * from users where userName like ?";
                params = new String[]{"%"+userName+"%"};
            }else if(!StringUtils.isNullOrEmpty(userID) && !StringUtils.isNullOrEmpty(userName))
            {
                sql = "select * from users where userName like ? and userID like ?";
                params = new String[]{"%"+userName+"%", "%"+userID+"%"};
            }else{
                sql = "select * from users";
                params = new String[]{};
            }
            //Connection connection,PreparedStatement preparedStatement,ResultSet resultSet,String sql,Object[] params
            rs = BaseDao.execute(connection, pstm, rs,sql, params);
            while(rs.next()){
                User _user = new User();
                _user.setUserID(rs.getString("userID"));
                _user.setPassword(rs.getString("password"));
                _user.setEmail(rs.getString("email"));
                _user.setUserName(rs.getString("userName"));
                userList.add(_user);
            }
            BaseDao.closeRecourse(connection,null,rs);
        }
        return userList;
    }
    @Override
    public boolean update(Connection connection, String userID, String userName, String password, String email) throws SQLException {
        PreparedStatement pstm = null;
        boolean flag = false;
        int rs = 0;
        if(connection!=null){
            String sql = "update users set userID = ? , userName = ? , password = ? , email = ? where userID = ?";
            String[] params = {userID,userName,password,email,userID};
            rs = BaseDao.execute(connection, pstm, sql, params);
            if(rs != 0){
                flag = true;
            }
            BaseDao.closeRecourse(connection,null,null);
        }
        return flag;
    }

    @Override
    public boolean delete(Connection connection, String userID) throws SQLException {
        PreparedStatement pstm = null;
        int rs;
        boolean flag = false;
        if(connection!=null){
            String sql = "delete from users where userID = ?";
            String[] params = {userID};
            //Connection connection,PreparedStatement preparedStatement,String sql,Object[] params
            rs = BaseDao.execute(connection, pstm,sql, params);
            if(rs != 0){
                flag = true;
            }
            BaseDao.closeRecourse(connection,null,null);
        }
        return flag;
    }


}

4.4 Filter模块

将请求和相应的编码格式转换成utf-8：CharacterEncoding.class

package com.qi.filter;


import javax.servlet.*;
import java.io.IOException;

public class CharacterEncodingFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        chain.doFilter(request, response);
    }
    @Override
    public void destroy() {

    }
}

4.5 pojo模块

对应数据库的User表：user.java

package com.qi.pojo;

public class User{
    private String userID;
    private String password;
    private String email;
    private String userName;

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserID() {
        return userID;
    }

    public void setUserID(String userID) {
        this.userID = userID;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

}

4.6 service模块

4.6.1 用户业务逻辑接口 UserService.class

package com.qi.service;

import com.qi.pojo.User;

import java.util.ArrayList;

public interface UserService {

    //用户登录
    public User login(String account,String password);

    //通过邮箱登录
    public User loginByEmail(String Email);

    //根据用户id修改密码
    public boolean updatePwd(String userId, String password);

    //查找用户密码
    public String selectPassword(String userId);

    //添加用户
    public boolean add(String userID, String userName, String password, String email) ;

    //获取所有用户
    public ArrayList<User> selectAll();

    //更新用户信息
    public boolean update(String userID, String userName, String password, String email);

    //删除用户
    public boolean delete(String userID );

    //根据用户ID和name获取用户
    public ArrayList<User> selectByIDName(String userID,String userName);


}

4.6.2 实现UserService接口：UserServiceImpl.java

package com.qi.service;

import com.qi.dao.BaseDao;
import com.qi.dao.user.UserDao;
import com.qi.dao.user.UserDaoImpl;
import com.qi.pojo.User;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;

public class UserServiceImpl implements UserService{
    //业务层都会调用Dao层，所以要引入Dao层
    private UserDao userDao;
    public UserServiceImpl(){
        userDao = new UserDaoImpl();
    }

    @Override
    public User login(String account, String password) {
        Connection connection = null;
        User user = null;
        try {
            connection = BaseDao.getConnection();
            user = userDao.getLoginUser(connection, account);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }
        return user;
    }

    @Override
    public User loginByEmail(String email) {
        Connection connection = null;
        User user = null;
        try {
            connection = BaseDao.getConnection();
            user = userDao.getLoginUserByEmail(connection, email);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }
        return user;
    }



    @Override
    public boolean updatePwd(String userId, String password) {

        boolean flag = false;
        Connection connection = null;
        //修改密码
        try {
            connection = BaseDao.getConnection();
            if(userDao.updatePwd(connection,userId,password) > 0){
                flag = true;
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }
        return flag;
    }

    @Override
    public String selectPassword(String userId) {

        boolean flag = false;
        Connection connection = null;
        String oldPassword = null;
        //修改密码
        try {
            connection = BaseDao.getConnection();
            oldPassword = userDao.selectPassword(connection, userId) ;
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }
        return oldPassword;
    }

    @Override
    public boolean add(String userID, String userName,String password, String email) {
        Connection connection = null;
        boolean flag = false;
        try {
            connection = BaseDao.getConnection();//Connection connection,PreparedStatement preparedStatement,String sql,Object[] params
            flag = userDao.add(connection, userID,userName,password,email);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }
        return flag;
    }

    @Override
    public ArrayList<User> selectAll() {
        Connection connection = null;
        ArrayList<User> userList = new ArrayList<User>();
        try {
            connection = BaseDao.getConnection();
            userList = userDao.selectAll(connection);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }

        return userList;
    }

    @Override
    public boolean update(String userID,String userName,String password, String email) {
        Connection connection = null;
        boolean flag = false;
        try {
            connection = BaseDao.getConnection();
            flag = userDao.update(connection, userID,userName,password,email);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }
        return flag;
    }

    @Override
    public boolean delete(String userID) {
        Connection connection = null;
        boolean flag = false;
        try {
            connection = BaseDao.getConnection();
            flag = userDao.delete(connection, userID);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }
        return flag;
    }

    @Override
    public ArrayList<User> selectByIDName(String userID,String userName) {
        Connection connection = null;
        ArrayList<User> userList = new ArrayList<User>();
        try {
            connection = BaseDao.getConnection();
            userList = userDao.selectByIDName(connection, userID,userName);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            BaseDao.closeRecourse(connection,null,null);
        }
        return userList;
    }
}

4.7 Servlet模块

4.7.1 用通过账户密码登录：Login.java

package com.qi.servlet.user;

import com.qi.pojo.User;
import com.qi.service.UserService;
import com.qi.service.UserServiceImpl;
import com.qi.util.Constants;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


public class LoginServlet extends HttpServlet {

    //Servlet
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //Servlet:控制层，调用业务层代码
        System.out.println("LoginServlet--start....");

        //获取用户名和密码
        String userID = req.getParameter("userID");
        String password = req.getParameter("password");

        //和数据库中的密码进行对比
        UserService userService = new UserServiceImpl();
        User user = userService.login(userID, password);
        if (user != null && password.equals(user.getPassword()))
        {
            //查到了这个人
            req.getSession().setAttribute(Constants.USER_SESSION,user);
            if(user.getUserID().equals("admin"))
            {
                resp.sendRedirect("/smbms_war/jsp/CRUDindex.jsp");
            }else{
                resp.sendRedirect("/smbms_war/jsp/successLogin.jsp");
            }
        }else{
            //查不到这个人
            req.setAttribute("message","用户名或密码不正确");
            req.getRequestDispatcher("/jsp/login.jsp").forward(req,resp);
//            resp.sendRedirect("/smbms_war/jsp/login.jsp");
        }
    }
}

4.7.2 通过邮箱登录：EmailLogin.java

package com.qi.servlet.user;

import com.qi.pojo.User;
import com.qi.service.UserService;
import com.qi.service.UserServiceImpl;
import com.qi.util.Constants;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class EmailLoginServlet extends HttpServlet {


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String inputIdentifyCode = req.getParameter("inputIdentifyCode");
        String email = (String) req.getSession().getAttribute("email");

        UserService userService = new UserServiceImpl();
        User user = userService.loginByEmail(email);
        String sessionIdentifyCode = (String) req.getSession().getAttribute("identifyCode");
        if(user != null && inputIdentifyCode.equals(sessionIdentifyCode))
        {
            req.getSession().setAttribute(Constants.USER_SESSION,user);
            resp.sendRedirect("/smbms_war/jsp/successLogin.jsp");
        }else{
            //查不到这个人
            req.setAttribute("message","验证码不正确");
            resp.sendRedirect("/smbms_war/jsp/login.jsp");
        }
    }
}

4.7.3 获取邮箱登录验证码：GetIndentifyCodeServlet.java

package com.qi.servlet.user;

import com.qi.util.MailJava;
import com.qi.util.MailJavaImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class GetIdentifyCodeServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String email = req.getParameter("email");
        req.getSession().setAttribute("email", email);

        try {
            MailJava mailJava = new MailJavaImpl();
            String identifyCode = mailJava.sendEmail(email);
            req.getSession().setAttribute("identifyCode",identifyCode);
            resp.sendRedirect("/smbms_war/jsp/login.jsp");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

4.7.4 忘记密码：ForgetPwdServlet.java

package com.qi.servlet.user;

import com.qi.pojo.User;
import com.qi.service.UserService;
import com.qi.service.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class ForgetPwdServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String inputID = (String) req.getSession().getAttribute("userID");
        String inputEmail = (String) req.getSession().getAttribute("email2");
        String inputIdentifyCode = req.getParameter("identifyCode");
        String inputPwd = req.getParameter("newPassword");
        String sessionIdentifyCode = (String) req.getSession().getAttribute("identifyCode");

        UserService userService = new UserServiceImpl();
        User user = userService.loginByEmail(inputEmail);

        //用户不为空且输入的ID和email匹配且输入的验证码和生成的验证码匹配，则修改密码
        if(user!=null)
        {
            if(user.getUserID().equals(inputID) )
            {
                if(inputIdentifyCode.equals(sessionIdentifyCode))
                {
                    UserService Service = new UserServiceImpl();
                    Service.updatePwd(inputID,inputPwd);
                    req.setAttribute("message","密码修改成功，请重新登陆");
                    req.getRequestDispatcher("jsp/login.jsp").forward(req,resp);

                }else{
                    req.setAttribute("forgetPwd","验证码错误，请重新输入");
                    req.getRequestDispatcher("/jsp/forgetPwd.jsp").forward(req,resp);
                }
            } else{
                req.setAttribute("forgetPwd","用户名错误，请重新输入");
                req.getRequestDispatcher("/jsp/forgetPwd.jsp").forward(req,resp);
            }
        }
        else{
            req.setAttribute("forgetPwd","邮箱不存在，请重新输入");
            req.getRequestDispatcher("/jsp/forgetPwd.jsp").forward(req,resp);
        }

    }
}

4.7.5 获取忘记密码的验证码：GetIdentifyCodeServlet2.java

package com.qi.servlet.user;

import com.qi.util.MailJava;
import com.qi.util.MailJavaImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class GetIdentifyCodeServlet2 extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String userID = req.getParameter("userID");
        req.getSession().setAttribute("userID", userID);
        String email2 = req.getParameter("email2");
        req.getSession().setAttribute("email2", email2);
        try {
            MailJava mailJava = new MailJavaImpl();
            String identifyCode = mailJava.sendEmail(email2);
            req.getSession().setAttribute("identifyCode",identifyCode);
//            req.getRequestDispatcher("/jsp/forgetPwd.jsp").forward(req,resp);
            resp.sendRedirect("/smbms_war/jsp/forgetPwd.jsp");

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

4.7.5 修改密码：ChangePwdServlet.java

package com.qi.servlet.user;

import com.mysql.cj.util.StringUtils;
import com.qi.pojo.User;
import com.qi.service.UserServiceImpl;
import com.qi.util.Constants;
import com.qi.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

//实现Servlet服用
public class ChangePwdServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //从Session里面拿ID
        Object o = req.getSession().getAttribute(Constants.USER_SESSION);

        String newpassword = req.getParameter("newpassword");
        String rnewpassword = req.getParameter("rnewpassword");
        String in_oldpassword = req.getParameter("oldpassword");
        String userID = ((User)o).getUserID();
        UserService userService = new UserServiceImpl();

        String oldpassword = userService.selectPassword(userID);
        System.out.println("oldpassword："+oldpassword);
        boolean flag = false;
        if(StringUtils.isNullOrEmpty(newpassword))
        {
            req.setAttribute("message","旧密码不能为空");
            req.getRequestDispatcher("jsp/changePwd.jsp").forward(req,resp);
        }
        else if(StringUtils.isNullOrEmpty(newpassword))
        {
            req.setAttribute("message","新密码不能为空");
            req.getRequestDispatcher("jsp/changePwd.jsp").forward(req,resp);
        }else if (StringUtils.isNullOrEmpty(rnewpassword))
        {
            req.setAttribute("message","重输新密码不能为空");
            req.getRequestDispatcher("jsp/changePwd.jsp").forward(req,resp);
        }else if(! newpassword.equals(rnewpassword))
        {
            req.setAttribute("message","两次输入的新密码不一致");
            req.getRequestDispatcher("jsp/changePwd.jsp").forward(req,resp);
        }else if(! in_oldpassword.equals(oldpassword)){
            req.setAttribute("message","旧密码输入错误");
            req.getRequestDispatcher("jsp/changePwd.jsp").forward(req,resp);
        }else{
            flag = userService.updatePwd(((User)o).getUserID(),newpassword);
            if(flag){
                req.setAttribute("message","密码修改成功，请重新登陆");
                req.getRequestDispatcher("jsp/login.jsp").forward(req,resp);
            }
            else{
                req.setAttribute("message","系统故障，密码修改失败");
                req.getRequestDispatcher("jsp/changePwd.jsp").forward(req,resp);

            }
        }

    }
}

4.7.6 增加用户：AddServleet.java

package com.qi.servlet.user;

import com.qi.service.UserService;
import com.qi.service.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class AddServlet extends HttpServlet {

    private  static  final  long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("进入了doPost");
        String userID = req.getParameter("userID");
        String userName = req.getParameter("userName");
        String password = req.getParameter("password");
        String email = req.getParameter("email");
        UserService userService = new UserServiceImpl();
        boolean flag = userService.add(userID,userName,password,email);
        if (flag) {
            req.setAttribute("message","添加用户成功");
        }else{
            req.setAttribute("message","添加用户失败");
        }

        req.getRequestDispatcher("ShowServlet").forward(req,resp);//内部重定向
    }

}

4.7.7 删除用户：DeleteServlet.java

package com.qi.servlet.user;

import com.mysql.cj.util.StringUtils;
import com.qi.pojo.User;
import com.qi.service.UserService;
import com.qi.service.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;

public class DeleteServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        String userID = req.getParameter("userID");
        boolean flag = false;
        UserService userService = new UserServiceImpl();
        if(!StringUtils.isNullOrEmpty(userID))
        {
            flag = userService.delete(userID);
        }
        if (flag) {
            req.setAttribute("message","删除用户成功");
        }else{
            req.setAttribute("message","删除用户失败");
        }
        ArrayList<User> userList = userService.selectAll();
        req.setAttribute("userList",userList);
        req.getRequestDispatcher("jsp/CRUDindex.jsp").forward(req,resp);
    }
}

4.7.8 修改用户信息：UpdateServlet.java

package com.qi.servlet.user;

import com.mysql.cj.util.StringUtils;
import com.qi.pojo.User;
import com.qi.service.UserService;
import com.qi.service.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;

public class UpdateServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String userID = req.getParameter("userID");
        if(! StringUtils.isNullOrEmpty(userID))
        {
            UserService userService = new UserServiceImpl();
            ArrayList<User> users = userService.selectByIDName(userID, null);
            User user = users.get(0);
            req.setAttribute("user",user);
        }
        req.getRequestDispatcher("jsp/update.jsp").forward(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        UserService userService = new UserServiceImpl();
        String new_userID = req.getParameter("userID");
        String new_userName = req.getParameter("userName");
        String new_password = req.getParameter("password");
        String new_sex = req.getParameter("email");
        boolean flag = userService.update(new_userID, new_userName, new_password, new_sex);
        if (flag) {
            req.setAttribute("message","编辑用户成功");
        }else{
            req.setAttribute("message","编辑用户失败");
        }
        req.getRequestDispatcher("ShowServlet").forward(req,resp);//内部重定向

    }
}

4.7.9 查找用户信息：SearchServlet.java

package com.qi.servlet.user;

import com.qi.pojo.User;
import com.qi.service.UserService;
import com.qi.service.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;

public class SearchServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        UserService userService = new UserServiceImpl();
        String userID = req.getParameter("userID");
        String userName = req.getParameter("userName");
        ArrayList<User> searchedUserList = userService.selectByIDName(userID, userName);
        req.setAttribute("userList",searchedUserList);
        req.getRequestDispatcher("jsp/CRUDindex.jsp").forward(req,resp);//内部重定向
    }
}

4.7.10 展示用户信息：ShowServlet.java

package com.qi.servlet.user;

import com.qi.pojo.User;
import com.qi.service.UserService;
import com.qi.service.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;

public class ShowServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        UserService userService = new UserServiceImpl();
        ArrayList<User> userList = userService.selectAll();
        req.setAttribute("userList",userList);
        req.getRequestDispatcher("jsp/CRUDindex.jsp").forward(req, resp);
    }
}

4.8 部署Servlet

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.LoginServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/login.do</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>getIdentifyCodeServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.GetIdentifyCodeServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>getIdentifyCodeServlet</servlet-name>
        <url-pattern>/getIdentifyCode.do</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>getIdentifyCodeServlet2</servlet-name>
        <servlet-class>com.qi.servlet.user.GetIdentifyCodeServlet2</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>getIdentifyCodeServlet2</servlet-name>
        <url-pattern>/getIdentifyCodeServlet2.do</url-pattern>
    </servlet-mapping>


    <servlet>
        <servlet-name>forgetPwdServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.ForgetPwdServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>forgetPwdServlet</servlet-name>
        <url-pattern>/forgetPwd.do</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>EmailLoginServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.EmailLoginServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>EmailLoginServlet</servlet-name>
        <url-pattern>/emailLogin.do</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>ChangePwdServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.ChangePwdServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>ChangePwdServlet</servlet-name>
        <url-pattern>/changePwd.do</url-pattern>
    </servlet-mapping>


    <servlet>
        <servlet-name>AddServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.AddServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>AddServlet</servlet-name>
        <url-pattern>/AddServlet</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>DeleteServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.DeleteServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>DeleteServlet</servlet-name>
        <url-pattern>/DeleteServlet</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>UpdateServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.UpdateServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>UpdateServlet</servlet-name>
        <url-pattern>/UpdateServlet</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>ShowServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.ShowServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ShowServlet</servlet-name>
        <url-pattern>/ShowServlet</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>SearchServlet</servlet-name>
        <servlet-class>com.qi.servlet.user.SearchServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>SearchServlet</servlet-name>
        <url-pattern>/SearchServlet</url-pattern>
    </servlet-mapping>



<!--    字符编码过滤器-->
    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>com.qi.filter.CharacterEncodingFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

<!--    设置欢迎界面-->
    <welcome-file-list>
        <welcome-file>login.jsp</welcome-file>
    </welcome-file-list>


</web-app>

5.核心操作

5.1邮箱登录

5.2 账号密码登录

5.3 修改密码

5.4 忘记密码

5.5 查找操作

5.6 添加操作

5.7 删除操作

5.8 修改操作

6.实验收获

在实验开始时，我对本实验要用到的技术一无所知，然后就在网上大量的查阅资料，得知了本实验可以用JavaWeb的相关知识解决。于是在B站学习相关的知识，学习了Http、Maven、Servlet、JSP、Session、JSTL标签、MVC三层架构、JDBC等相关方面的知识，终于对本实验的大概思路有了较为清晰的认识，然后基于学习过程中做的一些小样例进行了本次的开发。
在前端页面开发的过程中，遇到的最大问题是定位问题，就是每当页面进行重定位的时候，原本页面的CSS代码都失效了，页面布局完全乱了，还有就是在插入图片过程中，虽然路径写对了，但是仍然显示不出来图片。经过在网上查找相关的解决办法，我终于知道了，原来在每次重定位之后，JSP里所有的路径都变成了绝对路径，因此在写的时候不能只写相对路径如/forgetPwd.do 、 img src="/images/slide1.jpg" ，而应该在相对路径的前面加上${pageContext.request.contextPath } ，并且，尤其要注意$ 不能丢了，有一次检查bug花了两个多小时，最后发现是少加了个$ ……
在进行后端开发的过程中，我对MVC三层架构有了比较深刻的认识，MVC三层架构将软件分为View层、Model层、Controller层，其中View是视图层，负责数据展示和用户交互，主要体现在Jsp模块，Model是模型层，其又分为Service层和Dao层，前者主要进行事务的处理，Dao层主要是直接面向数据库，如取得结果集，将结果集封装之后返回给Service层,Controller层是处理用户发送的请求，根据不同的请求调用Service层的不同函数。
在开发过程中，我对Java的debug方法应用的更加熟练了，通过在不同位置设置断点，一步步的往下进行，我能够很快的找到逻辑错误出现在哪里，并且很快的排错。