Servlet登录小实例

1，目录及效果图
这里写图片描述

2，登录界面

<%@page contentType="text/html;charset=utf-8"%>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登入系统</title>
    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/css/style.css" />
</head>
<body>
    <div id="wrap">
        <div id="top_content">
            <div id="topheader">
                <h1 id="title">
                    <a href="#">我爱登陆HPE</a>
                </h1>
            </div>
        <div id="navigation"></div>
        <div id="content">
                <p id="whereami"></p>
                <h1>登入系统</h1>
                <p>&nbsp;</p>
                    <form action="${pageContext.request.contextPath}/SLogin" method="post">
                    <table  class="form_table">
                        <tr>
                            <td>用户名:</td>
                            <td>
                                <input type="text" name="username" class="inputgri" value="" />
                            </td>
                        </tr>
                        <tr>
                            <td>密码:</td>
                            <td>
                                <input type="password" name="pwd" class="inputgri" />
                            </td>
                        </tr>

                    </table>

                    <p>
                        <input type="submit" class="button" value="提交 &raquo;" /> <a
                            href="${pageContext.request.contextPath}/register.jsp">注册新用户</a>
                    </p>
                    <p>
                    </p>
                    </form>

            </div>
        </div>
        <div id="footer">
            <div id="footer_bg">[email protected]</div>
        </div>
    </div>
</body>
<script type="text/javascript">
    // 获取url中参数
    var flag = ${param.flag};
    if(flag == 1){
        alert("登录失败,请重新登录！");
    }
    if(flag == 2){
        alert("注册成功，请点击登录。");
    }
</script>
</html>

3，注册界面

<%@page contentType="text/html;charset=utf-8"%>
<% 
    String path = request.getContextPath(); 
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 
    // http :// localhost:8080/v1_LoginDemo_servlet
%> 
<!DOCTYPE html>
<html lang="en">
<head>
    <title>注册用户</title>
    <meta charset="UTF-8">
    <base href="<%=basePath %>">
    <link rel="stylesheet" type="text/css" href="css/style.css" />
    <script type="text/javascript" src="js/calendar.js"></script>
    <link type="text/css" rel="stylesheet" href="css/calendar-blue.css"></link>
</head>
<body>
    <div id="wrap">
        <div id="top_content">

            <div id="header">
                <div id="rightheader">
                    <p>
                        <span>${currentTime}</span>
                        <span><a href="${pageContext.request.contextPath}/index.jsp">退出</a></span><br />
                    </p>
                </div>

                <div id="topheader">
                    <h1 id="title">
                        <a href="#">我爱登陆</a>
                    </h1>
                </div>
                <div id="navigation"></div>
            </div>

                    <div id="content">
                    <p id="whereami">
                    </p>
                    <h1>
                        注册新用户
                    </h1>
                    <p>
                        &nbsp;
                    </p>

            <form action="${pageContext.request.contextPath}/SRegister" method="post" >
                <table>
                    <tr>
                        <td>用户名：</td>
                        <td><input type="text" name="username" value=""></td>
                    </tr>
                    <tr>
                        <td>密码：</td>
                        <td><input type="password" name="pwd"></td>
                    </tr>
                    <tr>
                        <td>确认密码：</td>
                        <td><input type="password" name="pwd1"></td>
                    </tr>
                    <tr>
                        <td>性别：</td>
                        <td>
                            <input type="radio" name="sex" value="1">男
                            <input type="radio" name="sex" value="0">女
                            <span id="sex_span"></span>
                        </td>
                    </tr>
                    <tr>
                        <td>个人爱好：</td>
                        <td>
                            <input type="checkbox" name="love" value="文学">文学
                            <input type="checkbox" name="love" value="影视">影视
                            <input type="checkbox" name="love" value="音乐">音乐
                            <input type="checkbox" name="love" value="体育">体育
                        </td>
                    </tr>
                    <tr>
                        <td>出生日期：</td>
                        <td>
                             <input type="text" id="birthday" name="birthday" >
                        </td>
                    </tr>
                    <tr>
                        <td>地址：</td>
                        <td><input type="text" name="address" value=""></td>
                    </tr>
                    <tr>
                        <td>邮箱：</td>
                        <td><input type="text" name="email" value=""></td>
                    </tr>
                    <tr>
                        <td colspan="2">
                        <input type="submit" name="update" value="提交" class="button">
                        <input type="reset" name="reset" value="重置" class="button">
                        </td>
                    </tr>
                </table>
            </form>
                </div>
            </div>

        <div id="footer">
            <div id="footer_bg">[email protected]</div>
        </div>
    </div>
</body>

<script type="text/javascript">

Calendar.setup({
inputField : "birthday",
ifFormat : "%Y-%m-%d",
showsTime : true,
timeFormat : "24"
});
</script>
</html>

4，修改界面

<%@page contentType="text/html;charset=utf-8"%>
<%@  taglib  uri="http://java.sun.com/jsp/jstl/functions"   prefix="fn"%>
<% 
    String path = request.getContextPath(); 
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 
    // http :// localhost:8080/v1_LoginDemo_servlet
%> 
<!DOCTYPE html>
<html lang="en">
<head>
    <title>修改用户</title>
    <meta charset="UTF-8">
    <base href="<%=basePath %>">
    <link rel="stylesheet" type="text/css" href="css/style.css" />
    <script type="text/javascript" src="js/calendar.js"></script>
    <link type="text/css" rel="stylesheet" href="css/calendar-blue.css"></link>
</head>
<body>
    <div id="wrap">
        <div id="top_content">

            <div id="header">
                <div id="rightheader">
                    <p>
                        <span>${currentTime}</span>
                        <span><a href="${pageContext.request.contextPath}/index.jsp">退出</a></span><br />
                    </p>
                </div>

                <div id="topheader">
                    <h1 id="title">
                        <a href="#">我爱登陆</a>
                    </h1>
                </div>
                <div id="navigation"></div>
            </div>

                    <div id="content">
                    <p id="whereami">
                    </p>
                    <h1>
                        注册新用户
                    </h1>
                    <p>
                        &nbsp;
                    </p>

            <form action="${pageContext.request.contextPath}/Ssave" method="post" >
            <input type="hidden" name="username" value="${user.getUsername()}">
                <table>
                    <tr>
                        <td>密码：</td>
                        <td><input type="password" name="pwd" value="${user.getPwd()}"></td>
                    </tr>
                    <tr>
                        <td>确认密码：</td>
                        <td><input type="password" name="pwd1"></td>
                    </tr>
                    <tr>
                        <td>性别：</td>
                        <td>
                            <input type="radio" name="sex" value="1" ${1 eq user.getSex()?"checked":""}>男
                            <input type="radio" name="sex" value="0" ${0 eq user.getSex()?"checked":""}>女
                            <span id="sex_span"></span>
                        </td>
                    </tr>
                    <tr>
                        <td>个人爱好：</td>
                        <td>
                            <input type="checkbox" name="love" value="文学" ${fn:contains(user.getLove(),'文学')?"checked":""} >文学
                            <input type="checkbox" name="love" value="影视" ${fn:contains(user.getLove(),'影视')?"checked":""} >影视
                            <input type="checkbox" name="love" value="音乐" ${fn:contains(user.getLove(),'音乐')?"checked":""} >音乐
                            <input type="checkbox" name="love" value="体育" ${fn:contains(user.getLove(),'体育')?"checked":""} >体育
                        </td>
                    </tr>
                    <tr>
                        <td>出生日期：</td>
                        <td>
                             <input type="text" id="birthday" name="birthday" value="${user.getBirthday()}">
                        </td>
                    </tr>
                    <tr>
                        <td>地址：</td>
                        <td><input type="text" name="address" value="${user.getAddress()}"></td>
                    </tr>
                    <tr>
                        <td>邮箱：</td>
                        <td><input type="text" name="email" value="${user.getEmail()}"></td>
                    </tr>
                    <tr>
                        <td colspan="2">
                        <input type="submit" name="update" value="提交" class="button">
                        <input type="reset" name="reset" value="重置" class="button">
                        </td>
                    </tr>
                </table>
            </form>
                </div>
            </div>

        <div id="footer">
            <div id="footer_bg">[email protected]</div>
        </div>
    </div>
</body>

<script type="text/javascript">

Calendar.setup({
inputField : "birthday",
ifFormat : "%Y-%m-%d",
showsTime : true,
timeFormat : "24"
});
</script>
</html>

5，主界面

<%@page import="java.util.ArrayList,com.hpe.bean.*"%>
<%@page contentType="text/html;charset=utf-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%>

<!--  权限判断 -->

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>用户列表</title>
<link rel="stylesheet" type="text/css"
    href="${pageContext.request.contextPath}/css/style.css" />
<script src="${pageContext.request.contextPath}/js/jquery-3.1.1.min.js"></script>
<style type="text/css">
    label {
        margin: 5px;
        font-size: 1.0em;
    }
</style>
</head>
<body>
    <div id="wrap">
        <div id="top_content">
            <div id="header">
                <div id="rightheader">
                    <p>
                        <span>${currentTime}</span>
                        <span><a href="${pageContext.request.contextPath}/index.jsp">退出</a></span><br />
                    </p>
                </div>

                <div id="topheader">
                    <h1 id="title">
                        <a href="#">我爱登录</a>
                    </h1>
                </div>
                <div id="navigation">
                    <ul>
                        <li><a>首页</a></li>
                        <li><a>新闻</a></li>
                        <li><a>作品</a></li>
                    </ul>
                </div>
            </div>
            <div id="content">
                <p id="whereami"></p>
                <h1>用户列表</h1>
                <form action="UserOpera" method="post">
                    <label>用户名</label><input type="text" name="username">
                    <label>性别</label><input type="text" name="sex">
                    <input type="submit" name="sel" value="查询">
                </form>
                <br><br>
                <table class="table">
                    <tr class="table_header">
                        <td>编号</td>
                        <td>用户名</td>
                        <td>密码</td>
                        <td>性别</td>
                        <td>爱好</td>
                        <td>地址</td>
                        <td>邮编</td>
                        <td>创建时间</td>
                        <td>操作</td>
                    </tr>
                    <c:forEach items="${list}" var="user" step="1">
                    <tr>
                        <td>${user.getId()}</td>
                        <td>${user.getUsername()}</td>
                        <td>${user.getPwd()}</td>
                        <td>${user.getSex()}</td>
                        <td>${user.getLove()}</td>
                        <td>${user.getAddress()}</td>
                        <td>${user.getEmail()}</td>
                        <td>${user.getCreateDate()}</td>
                        <td><a href="${pageContext.request.contextPath}/UserOpera?opea=add">增加</a>
                            <a href="${pageContext.request.contextPath}/UserOpera?name=${user.getUsername()}&opea=del">删除</a>
                            <a href="${pageContext.request.contextPath}/UserOpera?name=${user.getUsername()}&opea=modi">修改</a>
                        </td>
                    </tr>   
                    </c:forEach>
                </table>
            </div>
        </div>

        <div id="footer">
            <div id="footer_bg">[email protected]</div>
        </div>
    </div>
</body>
</html>

6，错误跳转界面

<%@ page language="java" import="java.util.*" 
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html lang="en">
   <head>
    <meta charset="UTF-8">
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <style type="text/css">
        .error{
            text-align: center;
        }
        span{
            color: red;
        }
    </style>
  </head>
  <body>
  <div class="error">
    <span>${msg}</span><br>
    <strong>请重新登录！！</strong><br>
  </div>
  </body>
</html>

7，servlet层

7.1. SLogin.java

 package com.hpe.servlet;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

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 com.hpe.bean.User;
import com.hpe.service.Login;

/**
 * Servlet implementation class Login
 */
@WebServlet("/SLogin")
public class SLogin extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        String username = request.getParameter("username");
        String pwd = request.getParameter("pwd");
        //封装数据
        User user=new User(username, pwd);
        //获取web应用路径
        String contextPath = request.getContextPath();

        //service层注入，业务处理
        Login login=new Login();
        int flag = login.login(user);
        if (flag==0) {
//          request.setAttribute("msg", "密码错误");
//          request.getRequestDispatcher("error.jsp").forward(request, response);
            //response.sendRedirect(contextPath+"/error.jsp");
            response.sendRedirect(contextPath+"/index.jsp?flag=1");
        }else if (flag==-1) {
//          request.setAttribute("msg", "用户名不存在");
//          request.getRequestDispatcher("error.jsp").forward(request, response);
            //response.sendRedirect(contextPath+"/error.jsp");
            response.sendRedirect(contextPath+"/index.jsp?flag=1");
        }else {
            //response.sendRedirect(contextPath+"/user/list.jsp");

            Date date=new Date();
            SimpleDateFormat sf=new SimpleDateFormat("yyyy-MM-dd");
            //创建时间
            String currentTime=sf.format(date);
            request.getSession().setAttribute("currentTime",currentTime );
            request.getSession().setAttribute("UserName",username );
            request.getRequestDispatcher("SList").forward(request, response);
        }
    }


    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

}

7.2. SRegister.java

 package com.hpe.servlet;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.Enumeration;

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 com.hpe.bean.User;
import com.hpe.service.Register;

/**
 * Servlet implementation class SRegister
 */
@WebServlet("/SRegister")
public class SRegister extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        String username = request.getParameter("username");
        String pwd = request.getParameter("pwd");
        String sex = request.getParameter("sex");

        //拼接字符串
        String[] loves=request.getParameterValues("love");
        String love=loves[0];
        for (int i = 1;loves!=null && i < loves.length; i++) {
            love+=","+loves[i];
        }


        String birthday = request.getParameter("birthday");
        String address = request.getParameter("address");
        String email = request.getParameter("email");

        Date date=new Date();
        SimpleDateFormat sf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        //创建时间
        String createDate=sf.format(date);
        //修改时间 默认第一次修改时间是创建时间
        String updateDate=createDate;

        User user=new User(username, pwd, sex, love, birthday, address, email, createDate, updateDate);

        //service注入
        Register register=new Register();
        boolean flag = register.register(user);

        //获取web应用路径
        String contextPath = request.getContextPath();

        if (flag) {
            response.sendRedirect(contextPath+"/index.jsp");
        }else {
            response.sendRedirect(contextPath+"/register.jsp?flag=1");
        }
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);

    }

}

7.3. SList.java

 package com.hpe.servlet;

import java.io.IOException;
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 com.hpe.service.UserOperate;

/**
 * Servlet implementation class SList
 */
@WebServlet("/SList")
public class SList extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        UserOperate userList=new UserOperate();
        List list = userList.list();
        //获取web应用路径
        String contextPath = request.getContextPath();
        request.setAttribute("list", list);
        request.getRequestDispatcher("user/list.jsp").forward(request, response);
        //response.sendRedirect(contextPath+"/user/list.jsp?list="+list);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

7.4. SUserOpera

 package com.hpe.servlet;

import java.io.IOException;
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 com.hpe.bean.User;
import com.hpe.service.UserOperate;

/**
 * Servlet implementation class UserOpera
 */
@WebServlet("/UserOpera")
public class SUserOpera extends HttpServlet {
    private static final long serialVersionUID = 1L;
    //service层注入
    UserOperate userOperate=new UserOperate();

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        String username = request.getParameter("name");
        String opea=request.getParameter("opea");
        //获取web应用路径
        String contextPath = request.getContextPath();
        if (opea.equals("del")) {
            int del = userOperate.del(username);
            if (del==1) {
                request.getRequestDispatcher("/SList").forward(request, response);
            }
            if (del==-1) {
                request.setAttribute("msg", "要删除的用户不存在");
                request.getRequestDispatcher("error.jsp").forward(request, response);
            }
            if (del==0) {
                request.setAttribute("msg", "删除失败");
                request.getRequestDispatcher("error.jsp").forward(request, response);
            }
        }
        if(opea.equals("add")) {
            response.sendRedirect(contextPath+"/register.jsp");
        }
        if(opea.equals("modi")) {
            User select = userOperate.select(username);
            request.setAttribute("user", select);
            request.getRequestDispatcher("modi.jsp").forward(request, response);
        }
    }

    /*
     * 混合查询
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //post提交方式 用于查询表单的处理    
            request.setCharacterEncoding("utf-8");
            String username = request.getParameter("username");
            String sex=request.getParameter("sex");
            List selectByName = userOperate.SelectByName(username, sex);
            request.setAttribute("list", selectByName);
            request.getRequestDispatcher("user/list.jsp").forward(request, response);

    }

}

7.5. Ssave.java用于更新后的保存

 package com.hpe.servlet;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

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 com.hpe.bean.User;
import com.hpe.service.UserOperate;

/**
 * Servlet implementation class Ssave
 */
@WebServlet("/Ssave")
public class Ssave extends HttpServlet {
    private static final long serialVersionUID = 1L;
    UserOperate userOperate=new UserOperate();

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        String username = request.getParameter("username");
        String pwd = request.getParameter("pwd");
        String sex = request.getParameter("sex");

        //拼接字符串
        String[] loves=request.getParameterValues("love");
        String love=loves[0];
        for (int i = 1;loves!=null && i < loves.length; i++) {
            love+=","+loves[i];
        }


        String birthday = request.getParameter("birthday");
        String address = request.getParameter("address");
        String email = request.getParameter("email");

        Date date=new Date();
        SimpleDateFormat sf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        //修改时间 默认第一次修改时间是创建时间
        String updateDate=sf.format(date);

        User user=new User(username, pwd, sex, love, birthday, address, email, updateDate);
        int flag = userOperate.modify(user);
        if (flag==1) {
            request.getRequestDispatcher("/SList").forward(request, response);
        }
        if (flag==-1){
            request.setAttribute("msg", "要修改的用户不存在");
            request.getRequestDispatcher("error.jsp").forward(request, response);
        }
        if (flag==0) {
            request.setAttribute("msg", "修改失败");
            request.getRequestDispatcher("error.jsp").forward(request, response);
        }
    }


    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

8，service层

8.1. Login.java

package com.hpe.service;

import com.hpe.base.BaseDao;
import com.hpe.bean.User;

public class Login {
    //dao层注入
    BaseDao<User> baseDao=new BaseDao<>();


    public int login(User u) {
        String sql="select * from t_user where userName=?";
        Object[] params= {u.getUsername()};
        User user = baseDao.get(sql, User.class, params);
        if (user==null) {
            //用户名不存在
            return -1;
        }else {
            if (u.getPwd().equals(user.getPwd())) {
                //登陆成功
                return 1;
            }else {
                //密码错误
                return 0;
            }
        }
    }
}

8.2.Register.java

package com.hpe.service;


import com.hpe.base.BaseDao;
import com.hpe.bean.User;


public class Register {
    //dao层注入
    BaseDao<User> baseDao=new BaseDao<>();

    public boolean register(User u) {
        String sql="insert into t_user(username,pwd,sex,love,birthday,address,email,createDate,updateDate) values(?,?,?,?,?,?,?,?,?)";

        boolean flag=false;
        Object[] params= {u.getUsername(),
                        u.getPwd(),
                        u.getSex(),
                        u.getLove(),
                        u.getBirthday(),
                        u.getAddress(),
                        u.getEmail(),
                        u.getCreateDate(),
                        u.getUpdateDate()
                        };
        try {
            boolean update = baseDao.update(sql, params);
            if (update) {
                flag=true;
            }else {
                flag=false;
            }

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

8.3. UserOperate.java

package com.hpe.service;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import com.hpe.base.BaseDao;
import com.hpe.bean.User;

public class UserOperate {
    //dao层注入
    BaseDao<User> baseDao=new BaseDao<>();

    /*
     * 获取list用户列表
     */
    public List list() {
        String sql="select * from t_user";
        Object[] params={}; 
        List<User> query = baseDao.query(sql, User.class, params);
        return query;
    }

    /*
     * 混合查询
     */
    public List SelectByName(String username,String sex) {
        StringBuilder sql = new StringBuilder("select  * from t_user where 1=1");


        if (username.length()>0&&sex.length()>0) {
            sql.append(" and username=? and sex=?");
            Object[] params= {username,sex};
            return baseDao.query(sql+"", User.class, params);   
        }else if(username.length()>0){
            sql.append(" and username=?");//注意空格
            Object[] params= {username};
            return baseDao.query(sql+"", User.class, params);   
        }else if(sex.length()>0){
            sql.append(" and sex=?");//注意空格
            Object[] params= {sex};
            return baseDao.query(sql+"", User.class, params);   
        }else {
             sql.append("");
             Object[] params= {};
            return baseDao.query(sql+"", User.class, params);   
        }
    }

    /*
     * 根据姓名删除
     */
    public int del(String username) {
        String sql1="select * from  t_user where username=?";
        String sql="delete from t_user where username=?";
        Object[] params= {username};
        int flag=0;
        User user = baseDao.get(sql1, User.class, params);
        if (user==null) {
            //要删除的用户不存在
            flag=-1;
        }else {
            try {
                boolean update = baseDao.update(sql, params);
                if (update) {
                    //删除成功
                    flag=1;
                }else {
                    //删除失败
                    flag=0;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return flag;
    }

    /*
     * 根据姓名单查询
     */
    public User select(String username) {
        String sql="select * from  t_user where username=?";
        Object[] params= {username};
        return baseDao.get(sql, User.class, params);
    }
    /*
     * 修改用户信息
     */
    public int modify(User u) {
        String sql1="select * from  t_user where username=?";
        String sql="update t_user set pwd=?,sex=?,love=?,birthday=?,address=?,email=?,updateDate=? where username=?";
        Date date=new Date();
        SimpleDateFormat sf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String updateDate=sf.format(date);
        Object[] params1= {u.getUsername()};
        Object[] params= {u.getPwd(),
                        u.getSex(),
                        u.getLove(),
                        u.getBirthday(),
                        u.getAddress(),
                        u.getEmail(),
                        u.getUpdateDate(),
                        u.getUsername()};
        int flag=0;
        User user = baseDao.get(sql1, User.class, params1);
        if (user==null) {
            //要修改的用户不存在
            flag=-1;
        }else {
            try {
                boolean update = baseDao.update(sql, params);
                if (update) {
                    //修改成功
                    flag=1;
                }else {
                    //修改失败
                    flag=0;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return flag;
    }


}

9,base层（Dao层）

package com.hpe.base;

import java.sql.*;
import java.util.List;

import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;

import com.hpe.util.MyDataSource;

/**
 * dao层公共方法类。
 * 增删改方法 ，默认支持事务，需要在业务类中，添加事务。
 * @author yaohuicheng
 *
 * @param <T>
 */
public class BaseDao<T>{

    private static ThreadLocal<Connection> tl = new ThreadLocal<Connection>();

    /**
     * 返回单个对象
     * @param <T>
     * 
     * @param sql
     * @param clazz
     * @param params
     *            如果没有参数就设为 Object[] params={}
     * @return
     */
    public <T> T get(String sql, Class<T> clazz, Object[] params) {
        T obj = null;
        Connection conn = null;
        try {
            conn = MyDataSource.getConnection();
            QueryRunner qRunner = new QueryRunner();
            obj = qRunner.query(conn, sql, new BeanHandler<T>(clazz), params);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DbUtils.closeQuietly(conn);
        }
        return obj;
    }

    /**
     * 返回多个对象
     * 
     * @param sql
     * @param clazz
     * @param params
     *            如果没有参数就设为 Object[] params={}
     * @return
     */
    public <T> List<T> query(String sql, Class<T> clazz, Object[] params) {
        List beans = null;
        Connection conn = null;
        try {
            conn = MyDataSource.getConnection();
            QueryRunner qRunner = new QueryRunner();
            beans = (List) qRunner.query(conn, sql, new BeanListHandler<T>(clazz), params);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DbUtils.closeQuietly(conn);
        }
        return beans;
    }

    /**
     * 返回增删改是否成功
     * 【注意，此方法没有关闭connection连接；需要在事务中关闭。 】
     * @param sql
     * @param params
     * @return
     * @throws Exception 
     */
    public boolean update(String sql, Object[] params) throws Exception {
        Connection conn = getConnection();
        boolean flag = false;
        QueryRunner qRunner = new QueryRunner();
        int i = qRunner.update(conn, sql, params);
        if (i > 0) {
            flag = true;
        }
        return flag;
    }


    /***
     * 批量操作，需要用到事务
     * 【注意，此方法没有关闭connection连接；需要在事务中关闭。 】
     * @param conn
     * @param sql
     * @param params
     * @return
     * @throws Exception 
     */
    public boolean batchUpdate(String sql, Object[][] params) throws Exception {
        QueryRunner qRunner = new QueryRunner();
        int result = 0;
        boolean flag = false;
        result = qRunner.batch(getConnection(), sql, params).length;
        if (result > 0) {
            flag = true;
        }
        return flag;
    }
    /**
     * 返回统计单值,
     * @param sql
     * @param params
     * @return
     */
    public Number getCount(String sql,Object[] params){
        Number value =0;
        Connection conn = null;
        try {
            conn = getConnection();
            QueryRunner qRunner = new QueryRunner();
            value  = (Number) qRunner.query(conn, sql, new ScalarHandler(), params);
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DbUtils.closeQuietly(conn);
        }
        return value;
    }
    /**
     * 返回主键,通常是执行insert语句时返回当前的主键值
     * 【注意，此方法没有关闭connection连接；需要在事务中关闭。 】
     * @param sql
     * @param params
     * @return
     * @throws Exception 
     */
    public Long getCurrentKey(String sql,Object[] params) throws Exception {
        Connection conn = null;
        Long key = 0l;
        conn = getConnection();
        QueryRunner qRunner = new QueryRunner();
        key = (Long) qRunner.insert(conn,sql, new ScalarHandler(1), params);
        return key;
   }

    /**
     * 从线程池中：获取数据连接。
     * @return 
     * @throws Exception
     */
    public Connection getConnection(){
        Connection conn = tl.get();
        if(conn ==null){
            conn = MyDataSource.getConnection();
        }
        return conn;
    }
    /***********事务处理方法************/
    /**
     * 开启事务
     */
    public static void beginTranscation(){
        Connection conn = tl.get();

        try {
            conn = MyDataSource.getConnection();
            conn.setAutoCommit(false);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        tl.set(conn);
    }
    /**
     * 结束事务
     * @throws SQLException
     */
    public static void endTranscation(){
        Connection conn = tl.get();
        try {
            conn.commit();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    /**
     * 回滚
     * @throws SQLException
     */
    public static void rollback(){
        Connection conn = tl.get();
        try {
            conn.rollback();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 事务处理，关闭资源
     * @throws SQLException
     */
    public static void closeConn(){
        Connection conn = tl.get();
        try {
            if(conn != null){
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        tl.remove();
    }


}

10，实体类

package com.hpe.bean;


/**
 * user对象实体类 t_user表对应的实体类。  面对对象的思想。
 * 1、实现view层和控制层数据交互。
 * 2、控制层和业务层之间的数据交互。
 * 3、数据层和dao之间的数据对应。
 * 
 * 使用的DBUtil ,数据库 表中的列 和实体类的属性，一一对应。
 * @author Administrator
 *
 */
public class User {
    private int id; //主键
    private String username;// 用户名
    private String pwd;// 密码
    private String sex;// 性别
    private String love;// 爱好
    private String birthday;// 生日
    private String address;// 地址
    private String email;// 邮箱
    private String createDate;// 数据创建时间
    private String updateDate;// 数据修改时间

    public User() {
        // TODO Auto-generated constructor stub
    }



    public User(String username, String pwd) {
        super();
        this.username = username;
        this.pwd = pwd;
    }



    public User(String username, String pwd, String sex, String love, String birthday, String address, String email,
            String updateDate) {
        super();
        this.username = username;
        this.pwd = pwd;
        this.sex = sex;
        this.love = love;
        this.birthday = birthday;
        this.address = address;
        this.email = email;
        this.updateDate = updateDate;
    }



    public User(String username, String pwd, String sex, String love, String birthday, String address,
            String email, String createDate, String updateDate) {
        super();
        this.username = username;
        this.pwd = pwd;
        this.sex = sex;
        this.love = love;
        this.birthday = birthday;
        this.address = address;
        this.email = email;
        this.createDate = createDate;
        this.updateDate = updateDate;
    }



    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPwd() {
        return pwd;
    }
    public void setPwd(String pwd) {
        this.pwd = pwd;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getLove() {
        return love;
    }
    public void setLove(String love) {
        this.love = love;
    }
    public String getBirthday() {
        return birthday;
    }
    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getCreateDate() {
        return createDate;
    }
    public void setCreateDate(String createDate) {
        this.createDate = createDate;
    }
    public String getUpdateDate() {
        return updateDate;
    }
    public void setUpdateDate(String updateDate) {
        this.updateDate = updateDate;
    }

}

11.工具类

package com.hpe.util;

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

import com.mchange.v2.c3p0.ComboPooledDataSource;

/**
 * 数据库连接池 c3p0数据源
 * 
 * @author Administrator
 */
public class MyDataSource {

    // 修改 数据库连接参
    public static String DRIVER;
    public static String URL;
    public static String USER;
    public static String PWD;
    public static int maxPoolSize;
    public static int minPoolSize;
    public static int initialPoolSize;
    public static int checkoutTimeout;
    private static final String filePath = "db.properties";

    private static ComboPooledDataSource cpDataSource = null;

    // 加载驱动
    static {
        try {
            // 读取配置文件，加载JDBC四大参数

            Properties config = new Properties();
            config.load(MyDataSource.class.getClassLoader().getResourceAsStream(filePath));
            DRIVER = config.getProperty("drivername");
            URL = config.getProperty("url");
            USER = config.getProperty("username");
            PWD = config.getProperty("password");

            maxPoolSize = Integer.parseInt(config.getProperty("maxPoolSize"));
            minPoolSize = Integer.parseInt(config.getProperty("minPoolSize"));
            initialPoolSize = Integer.parseInt(config.getProperty("initialPoolSize"));
            checkoutTimeout = Integer.parseInt(config.getProperty("checkoutTimeout"));

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    /**************** c3p0 数据库连接池 启动方法 ******************/
    private static void c3p0DataSource() throws Exception {
        cpDataSource = new ComboPooledDataSource();
        cpDataSource.setDriverClass(DRIVER);
        cpDataSource.setJdbcUrl(URL);
        cpDataSource.setUser(USER);
        cpDataSource.setPassword(PWD);
        cpDataSource.setMaxPoolSize(maxPoolSize);
        cpDataSource.setMinPoolSize(minPoolSize);
        cpDataSource.setInitialPoolSize(initialPoolSize);
        cpDataSource.setCheckoutTimeout(checkoutTimeout);
    }

    /**
     * c3p0数据库连接入
     * 
     * @return
     * @throws Exception
     */
    public static Connection getConnection() {
        Connection conn = null;

        try {
            if (cpDataSource == null) {
                c3p0DataSource();
            } 
            if(conn == null){
                conn = cpDataSource.getConnection();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return conn;
    }

}

12，配置文件db.properties

drivername=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/login_db?useUnicode=true&characterEncoding=utf-8
username=root
password=admin

maxPoolSize=20
minPoolSize=5
initialPoolSize=10
checkoutTimeout=10000

13，相应的js和css样式文件后续放上

包含：calendar.js
      jquery-3.1.1.min.js

14，相应的jar文件
这里写图片描述
15，总结
此次登录小项目用到了很多以前没注意到的东西，思想还是MVC分层的思想，数据库连接部分使用的是C3P0，同时还用到了apache的duutils工具类,servlet部分主要用到了转发和重定向，此外还牵扯到数据的集中传递方式，在后续的博客中会详细来讲，list列表遍历显示部分舍弃了以往的java代码与html代码混合的模式，采用的主要是EL表达式和jstl标签，总的来说还是受益匪浅的。
16，项目下载链接
链接：https://pan.baidu.com/s/1YP9_E5QLGWsMZGv-1B0k7g 密码：rc9v

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