今天完成一个web前端的项目

1.登陆的代码(包含过滤器)

1.登陆的login.jsp

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2020/3/27
  Time: 10:20
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8"/>
    <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
    <meta name="viewport" content="width=device-width, initial-scale=1"/>
    <title>管理员登录</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <!-- 2. jQuery导入,建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <script type="text/javascript">
    </script>
</head>
<script>
    function refreshCode() {
        //1.获取验证码对象
        var img_checkCode = document.getElementById("vcode");
        //2.修改路径,加上时间戳;
        img_checkCode.src = "${pageContext.request.contextPath}/checkCodeServlet?time="+new Date().getTime();

    }
</script>
<body>
<div class="container" style="width: 400px;">
    <h3 style="text-align: center;">管理员登录</h3>
    <form action="${pageContext.request.contextPath}/loginServlet" method="post">
        <div class="form-group">
            <label for="user">用户名:</label>
            <input type="text" name="username" class="form-control" id="user" placeholder="请输入用户名"/>
        </div>

        <div class="form-group">
            <label for="password">密码:</label>
            <input type="password" name="password" class="form-control" id="password" placeholder="请输入密码"/>
        </div>

        <div class="form-inline">
            <label for="vcode">验证码:</label>
            <input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="请输入验证码" style="width: 120px;"/>
            <a href="javascript:refreshCode()"><img src="${pageContext.request.contextPath}/checkCodeServlet" title="看不清点击刷新" id="vcode"/></a>
        </div>
        <hr/>
        <div class="form-group" style="text-align: center;">
            <input class="btn btn btn-primary" type="submit" value="登录">
        </div>
    </form>

    <!-- 出错显示的信息框 -->
    <div class="alert alert-warning alert-dismissible" role="alert">
        <button type="button" class="close" data-dismiss="alert" >
            <span>&times;</span></button>
        <strong><font color="red">${requestScope.login_msg}</font></strong>
    </div>
</div>
</body>
</html>

2.loginFilter(登陆的过滤器)

package cn.itcast.web.filter;

import org.junit.Test;
import org.w3c.dom.Text;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;

/**
 * 登陆验证的过滤器
 * Created by Administrator on 2020/3/29 18:26
 * @author Administrator
 */
@WebFilter("/*")
public class LoginFilter implements Filter {
    @Override
    public void destroy() {
    }
    @Override
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
        //0.强制转换
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) resp;
        //1.获取请求的路径
        String uri = request.getRequestURI();
        //如果路径中存在这些就放行,注意:将jsp、css等路径也进行过滤,不然页面显示不全
        if (uri.contains("/login.jsp")||
                uri.contains("/loginServlet")||
                uri.contains("/css/")||
                uri.contains("/fonts/")||
                uri.contains("/js/")||
                uri.contains("/checkCodeServlet")){
            //2.包含,直接放行
            chain.doFilter(req, resp);
        }else {
            //不包含直接跳转到登陆页面
            //3.从session中获取user
            Object user = request.getSession().getAttribute("user");
            if (user != null){
                //登陆了直接放行
                chain.doFilter(req, resp);
            }else {
                //没有登陆
                request.setAttribute("login_msg","您尚未登陆,请您登陆了再访问");
                request.getRequestDispatcher("/login.jsp").forward(request,response);
            }
        }


    }

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

    }

}

2.index.jsp进去查询界面

1.进入到list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="utf-8"/>
  <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <title>首页</title>

  <!-- 1. 导入CSS的全局样式 -->
  <link href="css/bootstrap.min.css" rel="stylesheet">
  <!-- 2. jQuery导入,建议使用1.9以上的版本 -->
  <script src="js/jquery-2.1.0.min.js"></script>
  <!-- 3. 导入bootstrap的js文件 -->
  <script src="js/bootstrap.min.js"></script>
  <script type="text/javascript">
  </script>
</head>
<body>

<div><h1>${user.name},欢迎您!!</h1>></div>
<div align="center">
  <a
          href="${pageContext.request.contextPath}/findUserByPageServlet" style="text-decoration:none;font-size:33px">查询所有用户信息
  </a>
</div>
</body>
</html>

3.list.jsp代码

里面包含了:
1.增,删,改,查
2.各种实现上述步骤的servlet类

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

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html lang="zh-CN">
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口:网页可以根据设置的宽度自动进行适配,在浏览器的内部虚拟一个容器,容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比,为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面,任何其他内容都*必须*跟随其后! -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <!-- 2. jQuery导入,建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<script>

    function deleteUser(id) {
        if (confirm("您确定要删除吗?")){
            location.href = "${pageContext.request.contextPath}/delUserServlet?id="+id;
        }
    }


    window.onload = function (ev) {
        //给删除选中按钮添加单击事件
        document.getElementById("delSelected").onclick = function (ev1) {
            var flag = false;
            //判断是否有选中条目
            var cbs = document.getElementsByName("uid");
            for (var i = 0; i < cbs.length; i++){
                //设置这些下面的cb的状态与first_cb相同
                if(cbs[i].checked){
                    flag = true;
                }
            }if (flag==false){
                alert("您没有选中任何要删除的数据!!")
            }
            if (flag){
                if (confirm("您确定要删除这些信息吗?")) {
                    //如果有条目被选中再提交表单
                    document.getElementById("form").submit();
                }
            }
        }
        document.getElementById("first_cb").onclick = function (ev1) {
            var cbs = document.getElementsByName("uid");
            for (var i = 0; i < cbs.length; i++){
                //设置这些下面的cb的状态与first_cb相同
                cbs[i].checked = this.checked;
            }
        }
    }

</script>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>
    <div class="jumbotron">
        <div style="text-align: center">

            <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
                <div class="form-group">
                    <label for="exampleInputName2">姓名</label>
                    <input type="text" name="name" value="${condition.name[0]}" class="form-control" id="exampleInputName2" >
                </div>
                <div class="form-group">
                    <label for="exampleInputName3">籍贯</label>
                    <input type="text" name="address" value="${condition.address[0]}" class="form-control" id="exampleInputName3" >
                </div>

                <div class="form-group">
                    <label for="exampleInputEmail2">邮箱</label>
                    <input type="email" name="email" value="${condition.email[0]}" class="form-control" id="exampleInputEmail2"  >
                </div>
                <button type="submit" class="btn btn-default">查询</button>
                <div style="float: right;">

                    <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp">添加联系人</a>
                    <a class="btn btn-primary" href="javascript:void(0);" id="delSelected">删除选中</a>

                </div>
            </form>

        </div>

    </div>

<form id="form" action="${pageContext.request.contextPath}/delSelectedServlet" method="post">
    <table border="1" class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox" style="margin-right: 5px" id="first_cb">全选</th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach items="${pb.list}" var="user" varStatus="s">
            <tr>
                <td><input type="checkbox" name="uid" value="${user.id}"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}">修改</a>&nbsp;
                    <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});">删除</a></td>
            </tr>

        </c:forEach>
    </table>
</form>
    <nav aria-label="Page navigation">
        <ul class="pagination">
            <li>
                <c:if test="${pb.currentPage>1}">
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage-1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </c:if>
            </li>

            <c:forEach begin="1" end="${pb.totalPage}" var="i">
                <c:if test="${pb.currentPage == i}">
                    <li class="active"><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
                </c:if>
                <c:if test="${pb.currentPage != i}">
                    <li><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
                </c:if>
            </c:forEach>

            <li>
                <c:if test="${pb.currentPage<pb.totalPage}">
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage+1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </c:if>
            </li>
            <span style="font-size: 25px;margin: 5px;">
                共条${pb.totalCount}记录,共${pb.totalPage}</span>
        </ul>
    </nav>
</div>
</body>
</html>

分页or不分页

1.分页

就是下面执行的代码

2.不分页

直接让它显示所有的信息

package cn.itcast.web.servlet;

import cn.itcast.domain.User;
import cn.itcast.service.UserService;
import cn.itcast.service.impl.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

/**
 * @author Administrator
 */
@WebServlet("/userListServlet")
public class UserListServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.调用UserService完成查询
        UserService service = new UserServiceImpl();
        List<User> users = service.findAll();
        //2.将list存入request域
        request.setAttribute("users",users);
        //3.转发到list.jsp
        request.getRequestDispatcher("/list.jsp").forward(request,response);
    }

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

以下均为分页的代码块

1.增,删,改,查

1.增加用户信息

package cn.itcast.web.servlet;

import cn.itcast.domain.User;
import cn.itcast.service.UserService;
import cn.itcast.service.impl.UserServiceImpl;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

/**
 * Created by Administrator on 2020/3/27 11:28
 */
@WebServlet("/addUserServlet")
public class AddUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //设置编码
        request.setCharacterEncoding("utf-8");
        //获取参数
        Map<String, String[]> map = request.getParameterMap();
        //封装对象
        User user = new User();
        try {
            BeanUtils.populate(user,map);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        //调用service保存
        UserService service = new UserServiceImpl();
        service.addUser(user);
        //跳转到userListServlet;
        response.sendRedirect(request.getContextPath()+"/findUserByPageServlet");
    }

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

2.删除用户信息

1.单独删除一个
package cn.itcast.web.servlet;

import cn.itcast.service.UserService;
import cn.itcast.service.impl.UserServiceImpl;

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

/**
 * Created by Administrator on 2020/3/27 11:45
 * @author Administrator
 */
@WebServlet("/delUserServlet")
public class DelUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取id
        String id = request.getParameter("id");
        //2.调用service删除
        UserService service = new UserServiceImpl();
        service.deleteUser(Integer.parseInt(id));

        //3.跳转到查询所有Servlet
        response.sendRedirect(request.getContextPath()+"/findUserByPageServlet");
    }

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

2.删除所有选框中的内容
package cn.itcast.web.servlet;

import cn.itcast.service.UserService;
import cn.itcast.service.impl.UserServiceImpl;

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

/**
 * @author Administrator
 */
@WebServlet("/delSelectedServlet")
public class DelSelectedServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取所有id
        String[] ids = request.getParameterValues("uid");
        //2.调用service删除
        UserService service = new UserServiceImpl();
        service.delSelectedUser(ids);

        //3.跳转查询所有Servlet
        response.sendRedirect(request.getContextPath()+"/findUserByPageServlet");
    }

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

3.修改用户信息

package cn.itcast.web.servlet;

import cn.itcast.domain.User;
import cn.itcast.service.UserService;
import cn.itcast.service.impl.UserServiceImpl;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

/**
 * @author Administrator
 */
@WebServlet("/updateUserServlet")
public class UpdateUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.设置编码
        request.setCharacterEncoding("utf-8");
        //2.获取map
        Map<String, String[]> map = request.getParameterMap();
        //3.封装对象
        User user = new User();
        try {
            BeanUtils.populate(user,map);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

        //4.调用Service修改
        UserService service = new UserServiceImpl();
        service.updateUser(user);

        //5.跳转到查询所有Servlet
        response.sendRedirect(request.getContextPath()+"/findUserByPageServlet");
    }

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

4.查询用户信息

package cn.itcast.web.servlet;

import cn.itcast.domain.User;
import cn.itcast.service.UserService;
import cn.itcast.service.impl.UserServiceImpl;

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

/**
 * @author Administrator
 */
@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取id
        String id = request.getParameter("id");
        //2.调用Service查询
        UserService service = new UserServiceImpl();
        User user = service.findUserById(Integer.parseInt(id));

        //3.将user存入request
        request.setAttribute("user",user);
        //4.转发到update.jsp
        request.getRequestDispatcher("/update.jsp").forward(request,response);
    }

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

package cn.itcast.web.servlet;

import cn.itcast.domain.PageBean;
import cn.itcast.domain.User;
import cn.itcast.service.UserService;
import cn.itcast.service.impl.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Map;

/**
 * Created by Administrator on 2020/3/27 20:47
 * @author Administrator
 */
@WebServlet("/findUserByPageServlet")
public class FindUserByPageServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //设置编码格式
        request.setCharacterEncoding("utf-8");

        //获取条件查询参数
        Map<String, String[]> condition = request.getParameterMap();


        //1.获取参数
        String currentPage = request.getParameter("currentPage");
        String rows = request.getParameter("rows");
        //如果从index.jsp传入过的没有参数,则给它赋予值
        if (currentPage == null || "".equals(currentPage)){
            currentPage = "1";
        }
        if (rows == null || "".equals(rows)){
            rows = "5";
        }
        //2.调用Service查询PageBean
        UserService service = new UserServiceImpl();
        PageBean<User> pb = service.findUserByPage(currentPage,rows,condition);
        //3.将PageBean存入request中
        request.setAttribute("pb",pb);
        //将查询条件存入request中
        request.setAttribute("condition",condition);
        //4.转发到list.jsp
        request.getRequestDispatcher("/list.jsp").forward(request,response);
    }

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

4.所有用到的底层代码

1.dao

1. notImplementDao

package cn.itcast.dao;

import cn.itcast.domain.User;

import java.util.List;
import java.util.Map;

/**
 * 用户操作的DAO
 */
public interface UserDao {


    public List<User> findAll();

    User findUserByUsernameAndPassword(String username, String password);

    void addUser(User user);

    void delete(int id);

    User findById(int i);

    void update(User user);

    int findTotalCount(Map<String, String[]> condition);

    List<User> findByPage(int start, int rows, Map<String, String[]> condition);
}

2. ImplementDao

package cn.itcast.dao.impl;

import cn.itcast.dao.UserDao;
import cn.itcast.domain.User;
import cn.itcast.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class UserDaoImpl implements UserDao {

    private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());

    @Override
    public List<User> findAll() {
        //使用JDBC操作数据库...
        //1.定义sql
        String sql = "select * from user";
        List<User> users = template.query(sql, new BeanPropertyRowMapper<User>(User.class));

        return users;
    }

    @Override
    public User findUserByUsernameAndPassword(String username, String password) {
        try {
            String sql = "select * from user where username = ? and password = ?";
            User user = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
            return user;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    @Override
    public void addUser(User user) {
        //1.定义sql
        String sql = "insert into user(id,name,gender,age,address,qq,email) values(null,?,?,?,?,?,?)";
        //2.执行sql
        template.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail());
    }

    @Override
    public void delete(int id) {
        //1.定义sql
        String sql = "delete from user where id = ?";
        //2.执行sql
        template.update(sql, id);
    }

    @Override
    public User findById(int id) {
        String sql = "select * from user where id = ?";
        return template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
    }

    @Override
    public void update(User user) {
        String sql = "update user set name = ?,gender = ? ,age = ? , address = ? , qq = ?, email = ? where id = ?";
        template.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
    }

    @Override
    public int findTotalCount(Map<String, String[]> condition) {
        //1.定义模板初始化sql
        String sql = "select count(*) from user where 1 = 1 ";
        StringBuilder sb = new StringBuilder(sql);
        //2.遍历map
        Set<String> keySet = condition.keySet();
        //定义参数的集合
        List<Object> params = new ArrayList<Object>();
        for (String key : keySet) {

            //排除分页条件参数
            if("currentPage".equals(key) || "rows".equals(key)){
                continue;
            }

            //获取value
            String value = condition.get(key)[0];
            //判断value是否有值
            if(value != null && !"".equals(value)){
                //有值
                sb.append(" and "+key+" like ? ");
                params.add("%"+value+"%");//?条件的值
            }
        }
        System.out.println(sb.toString());
        System.out.println(params);

        return template.queryForObject(sb.toString(),Integer.class,params.toArray());
    }

    @Override
    public List<User> findByPage(int start, int rows, Map<String, String[]> condition) {
        String sql = "select * from user  where 1 = 1 ";

        StringBuilder sb = new StringBuilder(sql);
        //2.遍历map
        Set<String> keySet = condition.keySet();
        //定义参数的集合
        List<Object> params = new ArrayList<Object>();
        for (String key : keySet) {

            //排除分页条件参数
            if("currentPage".equals(key) || "rows".equals(key)){
                continue;
            }

            //获取value
            String value = condition.get(key)[0];
            //判断value是否有值
            if(value != null && !"".equals(value)){
                //有值
                sb.append(" and "+key+" like ? ");
                //?条件的值
                params.add("%"+value+"%");
            }
        }

        //添加分页查询
        sb.append(" limit ?,? ");
        //添加分页查询参数值
        params.add(start);
        params.add(rows);
        sql = sb.toString();

        return template.query(sql,new BeanPropertyRowMapper<User>(User.class),params.toArray());
    }
}

2.service

1.notImplementService

package cn.itcast.service;

import cn.itcast.domain.PageBean;
import cn.itcast.domain.User;

import java.util.List;
import java.util.Map;

/**
 * 用户管理的业务接口
 */
public interface UserService {

    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    public User login(User user);

    void addUser(User user);

    void deleteUser(int id);

    User findUserById(int id);

    void updateUser(User user);

    void delSelectedUser(String[] id);


    /**
     * 分页查询,分页条件查询
     * 封装当前页码返回的user集合对象;
     * @return
     */
    PageBean<User> findUserByPage(String currentPage, String rows, Map<String, String[]> condition);
}

2.ImplementService

package cn.itcast.service.impl;

import cn.itcast.dao.UserDao;
import cn.itcast.dao.impl.UserDaoImpl;
import cn.itcast.domain.PageBean;
import cn.itcast.domain.User;
import cn.itcast.service.UserService;

import java.util.List;
import java.util.Map;

public class UserServiceImpl implements UserService {
    private UserDao dao = new UserDaoImpl();

    @Override
    public List<User> findAll() {
        //调用Dao完成查询
        return dao.findAll();
    }

    @Override
    public User login(User user) {
        return dao.findUserByUsernameAndPassword(user.getUsername(),user.getPassword());
    }

    @Override
    public void addUser(User user) {
        dao.addUser(user);
    }

    @Override
    public void deleteUser(int id) {
        dao.delete(id);
    }

    @Override
    public User findUserById(int id) {
        return dao.findById(id);
    }

    @Override
    public void updateUser(User user) {
        dao.update(user);
    }

    @Override
    public void delSelectedUser(String[] id) {
        for (String s : id) {
            int i = Integer.parseInt(s);
            dao.delete(i);
        }
    }

    @Override
    public PageBean<User> findUserByPage(String _currentPage, String _rows, Map<String, String[]> condition) {

        int currentPage = Integer.parseInt(_currentPage);
        int rows = Integer.parseInt(_rows);
        //1.创建空的PageBean对象
        PageBean<User> pb = new PageBean<User>();
        //2.设置当前页面的属性和rows属性;
        pb.setCurrentPage(currentPage);
        pb.setRows(rows);
        //3.调用dao查询总记录数
        int totalCount = dao.findTotalCount(condition);
        pb.setTotalCount(totalCount);
        //4.调用dao查询List集合
        //计算开始的索引
        int start = (currentPage-1) * rows;
        List<User> list = dao.findByPage(start,rows,condition);
        pb.setList(list);
        //5.计算总页码数
        int totalPage = (totalCount % rows) ==0 ? (totalCount / rows) : (totalCount / rows + 1);
        pb.setTotalPage(totalPage);
        //6.返回PageBean对象
        return pb;
    }
}

5.所有的jsp页面

1.add

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2020/3/27
  Time: 11:26
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!-- HTML5文档-->
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html lang="zh-CN">
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口:网页可以根据设置的宽度自动进行适配,在浏览器的内部虚拟一个容器,容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比,为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面,任何其他内容都*必须*跟随其后! -->
    <title>添加用户</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <!-- 2. jQuery导入,建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
    <center><h3>添加联系人页面</h3></center>
    <form action="${pageContext.request.contextPath}/addUserServlet" method="post">
        <div class="form-group">
            <label for="name">姓名:</label>
            <input type="text" class="form-control" id="name" name="name" placeholder="请输入姓名">
        </div>

        <div class="form-group">
            <label>性别:</label>
            <input type="radio" name="gender" value="男" checked="checked"/><input type="radio" name="gender" value="女"/></div>

        <div class="form-group">
            <label for="age">年龄:</label>
            <input type="text" class="form-control" id="age" name="age" placeholder="请输入年龄">
        </div>

        <div class="form-group">
            <label for="address">籍贯:</label>
            <select name="address" class="form-control" id="jiguan">
                <option value="广东">广东</option>
                <option value="广西">广西</option>
                <option value="湖南">湖南</option>
            </select>
        </div>

        <div class="form-group">
            <label for="qq">QQ:</label>
            <input type="text" class="form-control" name="qq" placeholder="请输入QQ号码"/>
        </div>

        <div class="form-group">
            <label for="email">Email:</label>
            <input type="email" class="form-control" name="email" placeholder="请输入邮箱地址"/>
        </div>

        <div class="form-group" style="text-align: center">
            <input class="btn btn-primary" type="submit" value="提交" />
            <input class="btn btn-default" type="reset" value="重置" />
            <input class="btn btn-default" type="submit" value="返回" href="${pageContext.request.contextPath}/list.jsp" />
        </div>
    </form>
</div>
</body>
</html>

3.list

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

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html lang="zh-CN">
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口:网页可以根据设置的宽度自动进行适配,在浏览器的内部虚拟一个容器,容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比,为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面,任何其他内容都*必须*跟随其后! -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <!-- 2. jQuery导入,建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<script>

    function deleteUser(id) {
        if (confirm("您确定要删除吗?")){
            location.href = "${pageContext.request.contextPath}/delUserServlet?id="+id;
        }
    }


    window.onload = function (ev) {
        //给删除选中按钮添加单击事件
        document.getElementById("delSelected").onclick = function (ev1) {
            var flag = false;
            //判断是否有选中条目
            var cbs = document.getElementsByName("uid");
            for (var i = 0; i < cbs.length; i++){
                //设置这些下面的cb的状态与first_cb相同
                if(cbs[i].checked){
                    flag = true;
                }
            }if (flag==false){
                alert("您没有选中任何要删除的数据!!")
            }
            if (flag){
                if (confirm("您确定要删除这些信息吗?")) {
                    //如果有条目被选中再提交表单
                    document.getElementById("form").submit();
                }
            }
        }
        document.getElementById("first_cb").onclick = function (ev1) {
            var cbs = document.getElementsByName("uid");
            for (var i = 0; i < cbs.length; i++){
                //设置这些下面的cb的状态与first_cb相同
                cbs[i].checked = this.checked;
            }
        }
    }

</script>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>
    <div class="jumbotron">
        <div style="text-align: center">

            <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
                <div class="form-group">
                    <label for="exampleInputName2">姓名</label>
                    <input type="text" name="name" value="${condition.name[0]}" class="form-control" id="exampleInputName2" >
                </div>
                <div class="form-group">
                    <label for="exampleInputName3">籍贯</label>
                    <input type="text" name="address" value="${condition.address[0]}" class="form-control" id="exampleInputName3" >
                </div>

                <div class="form-group">
                    <label for="exampleInputEmail2">邮箱</label>
                    <input type="email" name="email" value="${condition.email[0]}" class="form-control" id="exampleInputEmail2"  >
                </div>
                <button type="submit" class="btn btn-default">查询</button>
                <div style="float: right;">

                    <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp">添加联系人</a>
                    <a class="btn btn-primary" href="javascript:void(0);" id="delSelected">删除选中</a>

                </div>
            </form>

        </div>

    </div>

<form id="form" action="${pageContext.request.contextPath}/delSelectedServlet" method="post">
    <table border="1" class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox" style="margin-right: 5px" id="first_cb">全选</th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach items="${pb.list}" var="user" varStatus="s">
            <tr>
                <td><input type="checkbox" name="uid" value="${user.id}"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}">修改</a>&nbsp;
                    <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});">删除</a></td>
            </tr>

        </c:forEach>
    </table>
</form>
    <nav aria-label="Page navigation">
        <ul class="pagination">
            <li>
                <c:if test="${pb.currentPage>1}">
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage-1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </c:if>
            </li>

            <c:forEach begin="1" end="${pb.totalPage}" var="i">
                <c:if test="${pb.currentPage == i}">
                    <li class="active"><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
                </c:if>
                <c:if test="${pb.currentPage != i}">
                    <li><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
                </c:if>
            </c:forEach>

            <li>
                <c:if test="${pb.currentPage<pb.totalPage}">
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage+1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </c:if>
            </li>
            <span style="font-size: 25px;margin: 5px;">
                共条${pb.totalCount}记录,共${pb.totalPage}</span>
        </ul>
    </nav>
</div>
</body>
</html>

4.login

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2020/3/27
  Time: 10:20
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8"/>
    <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
    <meta name="viewport" content="width=device-width, initial-scale=1"/>
    <title>管理员登录</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <!-- 2. jQuery导入,建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <script type="text/javascript">
    </script>
</head>
<script>
    function refreshCode() {
        //1.获取验证码对象
        var img_checkCode = document.getElementById("vcode");
        //2.修改路径,加上时间戳;
        img_checkCode.src = "${pageContext.request.contextPath}/checkCodeServlet?time="+new Date().getTime();

    }
</script>
<body>
<div class="container" style="width: 400px;">
    <h3 style="text-align: center;">管理员登录</h3>
    <form action="${pageContext.request.contextPath}/loginServlet" method="post">
        <div class="form-group">
            <label for="user">用户名:</label>
            <input type="text" name="username" class="form-control" id="user" placeholder="请输入用户名"/>
        </div>

        <div class="form-group">
            <label for="password">密码:</label>
            <input type="password" name="password" class="form-control" id="password" placeholder="请输入密码"/>
        </div>

        <div class="form-inline">
            <label for="vcode">验证码:</label>
            <input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="请输入验证码" style="width: 120px;"/>
            <a href="javascript:refreshCode()"><img src="${pageContext.request.contextPath}/checkCodeServlet" title="看不清点击刷新" id="vcode"/></a>
        </div>
        <hr/>
        <div class="form-group" style="text-align: center;">
            <input class="btn btn btn-primary" type="submit" value="登录">
        </div>
    </form>

    <!-- 出错显示的信息框 -->
    <div class="alert alert-warning alert-dismissible" role="alert">
        <button type="button" class="close" data-dismiss="alert" >
            <span>&times;</span></button>
        <strong><font color="red">${requestScope.login_msg}</font></strong>
    </div>
</div>
</body>
</html>

5.update

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2020/3/27
  Time: 9:45
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html lang="zh-CN">
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>修改用户</title>

    <link href="css/bootstrap.min.css" rel="stylesheet">
    <script src="js/jquery-2.1.0.min.js"></script>
    <script src="js/bootstrap.min.js"></script>

</head>
<body>
<div class="container" style="width: 400px;">
    <h3 style="text-align: center;">修改联系人</h3>
    <form action="${pageContext.request.contextPath}/updateUserServlet" method="post">
        <%--隐藏域 提交id--%>
        <input type="hidden" name="id" value="${user.id}">
        <div class="form-group">
            <label for="name">姓名:</label>
            <input type="text" class="form-control" id="name" name="name" value="${user.name}" readonly="readonly" placeholder="请输入姓名" />
        </div>

        <div class="form-group" >
            <label >性别:</label>

            <c:if test="${ user.gender == '男'}">
            <input type="radio" name="gender" value="男" checked /><input type="radio" name="gender" value="女"  /></c:if>

            <c:if test="${user.gender == '女'}">
                <input type="radio" name="gender" value="男"  /><input type="radio" name="gender" value="女" checked  /></c:if>

        </div>

        <div class="form-group">
            <label for="age">年龄:</label>
            <input type="text" class="form-control" id="age"  name="age" value="${user.age}" placeholder="请输入年龄" />
        </div>

        <div class="form-group">
            <label for="address">籍贯:</label>
            <select name="address" class="form-control" >
                <c:if test="${user.address == '广东'}">
                    <option value="广东" selected>广东</option>
                    <option value="广西">广西</option>
                    <option value="湖南">湖南</option>
                </c:if>
                <c:if test="${user.address == '广西'}">
                    <option value="广东" >广东</option>
                    <option value="广西" selected>广西</option>
                    <option value="湖南">湖南</option>
                </c:if>
                <c:if test="${user.address == '湖南'}">
                    <option value="广东" >广东</option>
                    <option value="广西">广西</option>
                    <option value="湖南" selected>湖南</option>
                </c:if>
                    <option value="${user.address}" selected>${user.address}</option>
                    <option value="广东">广东</option>
                    <option value="广西">广西</option>
                    <option value="湖南">湖南</option>
            </select>
        </div>

        <div class="form-group">
            <label for="qq">QQ:</label>
            <input type="text" class="form-control" name="qq" value="${user.qq}" placeholder="请输入QQ号码"/>
        </div>

        <div class="form-group">
            <label for="email">Email:</label>
            <input type="text" class="form-control" name="email" value="${user.email}" placeholder="请输入邮箱地址"/>
        </div>

        <div class="form-group" style="text-align: center">
            <input class="btn btn-primary" type="submit" value="提交" />
            <input class="btn btn-default" type="reset" value="重置" />
            <input class="btn btn-default" type="button" value="返回"/>
        </div>
    </form>
</div>
</body>
</html>

5.domain代码块

1.PageBean封装对象

package cn.itcast.domain;

import java.util.List;

/**
 * Created by Administrator on 2020/3/27 20:41
 * @author Administrator
 */
public class PageBean<T> {
    //总记录数
    private int totalCount;
    //总页码数
    private int totalPage;
    //每页的数据list集合
    private List<T> list;
    //当前页码数
    private int currentPage;
    //每页显示的条数
    private int rows;

    @Override
    public String toString() {
        return "PageBean{" +
                "totalCount=" + totalCount +
                ", totalPage=" + totalPage +
                ", list=" + list +
                ", currentPage=" + currentPage +
                ", rows=" + rows +
                '}';
    }

    public int getTotalCount() {
        return totalCount;
    }

    public void setTotalCount(int totalCount) {
        this.totalCount = totalCount;
    }

    public int getTotalPage() {
        return totalPage;
    }

    public void setTotalPage(int totalPage) {
        this.totalPage = totalPage;
    }

    public List<T> getList() {
        return list;
    }

    public void setList(List<T> list) {
        this.list = list;
    }

    public int getCurrentPage() {
        return currentPage;
    }

    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
    }

    public int getRows() {
        return rows;
    }

    public void setRows(int rows) {
        this.rows = rows;
    }
}

2.User封装对象

package cn.itcast.domain;

public class User {
    private int id;
    private String name;
    private String gender;
    private int age;
    private String address;
    private String qq;
    private String email;
    private String username;
    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

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

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getQq() {
        return qq;
    }

    public void setQq(String qq) {
        this.qq = qq;
    }

    public String getEmail() {
        return email;
    }

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

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                ", age=" + age +
                ", address='" + address + '\'' +
                ", qq='" + qq + '\'' +
                ", email='" + email + '\'' +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

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