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Java--小项目（登录、增删改查、分页、搜索）

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概念

技术选型

Servlet、JSP、MySQL、JDBCTempleat、Duird、BeanUtilS、tomcat

功能介绍

登录功能，列表展示，数据添加，数据编辑，数据删除，批量删除，分页展示，关键字搜索

创建JavaWeb项目

导入依赖

添加页面文件

数据库

create database little; -- 创建数据库
use little; 			   -- 使用数据库
create table user(   -- 创建表
	id int primary key auto_increment,
	name varchar(20) not null,
	gender varchar(5),
	age int,
	address varchar(32),
	qq	varchar(20),
	email varchar(50,
	username varchar(32),
  password varchar(32),
);

列表展示

思路

首先我们需要一组列表的数据，那么我们就需要一个相对应servlet，通过我们的三层架构，使用service同一做接口，然后调用dao层使用JBDC操作数据库，这样我们可以获得一个map集合的数据，然后就是渲染数据到jsp页面了，通过JSTL和EL把数据循环渲染到表里面，达到列表的展示

list.jsp

<%--
  Created by IntelliJ IDEA.
  User: tanglei
  Date: 2020/6/28
  Time: 下午2:15
  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">
    <!-- 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。
     默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>
    <table border="1" class="table table-bordered table-hover">
        <tr class="success">
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>
        <c:forEach items="${users}" var="user" varStatus="s">
            <tr>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="update.html">修改</a>&nbsp;<a class="btn btn-default btn-sm"
                                                                                        href="">删除</a></td>
            </tr>
        </c:forEach>

        <tr>
            <td colspan="8" align="center"><a class="btn btn-primary" href="add.html">添加联系人</a></td>
        </tr>
    </table>
</div>
</body>
</html>

servlet

代码文件很多，就不一一展示了

UserListServlet

package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.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;

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

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

测试

<%--
  Created by IntelliJ IDEA.
  User: tanglei
  Date: 2020/6/28
  Time: 下午7:37
  To change this template use File | Settings | File Templates.
--%>
<%@ 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>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">
        function refreshCode() {
            let vcode = document.getElementById("vcode");
            vcode.src = "${pageContext.request.contextPath}/checkCodeServlet?=" + new Date().getTime();
        }
    </script>
</head>
<body>
<div class="container" style=" 400px;">
    <h3 style="text-align: center;">管理员登录</h3>
    <form action="${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=" 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>${login_msg}</strong>
    </div>
</div>
</body>
</html>

LoginServlet

package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //设置编码
        req.setCharacterEncoding("utf-8");
        //传递过来的验证码
        String verifycode = req.getParameter("verifycode");
        HttpSession session = req.getSession();
        //session里面的验证码
        String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER");
        session.removeAttribute("CHECKCODE_SERVER");
        //比对验证码
        if (!checkcode_server.equalsIgnoreCase(verifycode)) {
            req.setAttribute("login_msg", "验证码错误");
            req.getRequestDispatcher("/login.jsp").forward(req, resp);
            return;
        }

        Map<String, String[]> parameterMap = req.getParameterMap();
        User user = new User();
        try {
            BeanUtils.populate(user, parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

        UserService userService = new UserServiceImpl();
        User loginUser = userService.login(user);
        if(loginUser != null){
            session.setAttribute("user",loginUser);
            resp.sendRedirect(req.getContextPath()+"/index.jsp");
        }else {
            req.setAttribute("login_msg", "登录失败");
            req.getRequestDispatcher("/login.jsp").forward(req, resp);
        }


    }

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

CheckCodeServlet

package cn.guizimo.little.web.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 验证码
 */
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
	public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
		
		//服务器通知浏览器不要缓存
		response.setHeader("pragma","no-cache");
		response.setHeader("cache-control","no-cache");
		response.setHeader("expires","0");
		
		//在内存中创建一个长80，宽30的图片，默认黑色背景
		//参数一：长
		//参数二：宽
		//参数三：颜色
		int width = 80;
		int height = 30;
		BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
		
		//获取画笔
		Graphics g = image.getGraphics();
		//设置画笔颜色为灰色
		g.setColor(Color.GRAY);
		//填充图片
		g.fillRect(0,0, width,height);
		
		//产生4个随机验证码，12Ey
		String checkCode = getCheckCode();
		//将验证码放入HttpSession中
		request.getSession().setAttribute("CHECKCODE_SERVER",checkCode);
		
		//设置画笔颜色为黄色
		g.setColor(Color.YELLOW);
		//设置字体的小大
		g.setFont(new Font("黑体",Font.BOLD,24));
		//向图片上写入验证码
		g.drawString(checkCode,15,25);
		
		//将内存中的图片输出到浏览器
		//参数一：图片对象
		//参数二：图片的格式，如PNG,JPG,GIF
		//参数三：图片输出到哪里去
		ImageIO.write(image,"PNG",response.getOutputStream());
	}
	/**
	 * 产生4位随机字符串 
	 */
	private String getCheckCode() {
		String base = "0123456789ABCDEFGabcdefg";
		int size = base.length();
		Random r = new Random();
		StringBuffer sb = new StringBuffer();
		for(int i=1;i<=4;i++){
			//产生0到size-1的随机值
			int index = r.nextInt(size);
			//在base字符串中获取下标为index的字符
			char c = base.charAt(index);
			//将c放入到StringBuffer中去
			sb.append(c);
		}
		return sb.toString();
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		this.doGet(request,response);
	}
}

测试

添加人员

思路

添加操作就是把jsp提交的表单的数据向数据库里面存储，过程为jsp->servlet->service->dao

add.jsp

<%--
  Created by IntelliJ IDEA.
  User: tanglei
  Date: 2020/6/28
  Time: 下午8:55
  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。
     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"/>男
            <input type="radio" name="gender" value="女"/>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="text" 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="button" value="返回" />
        </div>
    </form>
</div>
</body>
</html>

AddUserServlet

package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.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;

@WebServlet("/addUserServlet")
public class AddUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        Map<String, String[]> parameterMap = req.getParameterMap();
        User user = new User();
        try {
            BeanUtils.populate(user,parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        UserService userService = new UserServiceImpl();
        userService.addUser(user);
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }

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

测试

修改

思路

首先我们需要在打开jsp页面的时候就查询到这样的一条记录，通过这一条记录的id作为表单的隐藏域，在servlet里面将数据进行保存即可

update.jsp

<%--
  Created by IntelliJ IDEA.
  User: tanglei
  Date: 2020/6/29
  Time: 上午10:44
  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=" 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 />男
                <input type="radio" name="gender" value="女"  />女
            </c:if>

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


        </div>

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

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

                <c:if test="${user.address == '北京'}">
                    <option value="陕西" >陕西</option>
                    <option value="北京" selected>北京</option>
                    <option value="上海">上海</option>
                </c:if>

                <c:if test="${user.address == '上海'}">
                    <option value="陕西" >陕西</option>
                    <option value="北京">北京</option>
                    <option value="上海" selected>上海</option>
                </c:if>
            </select>
        </div>

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

        <div class="form-group">
            <label for="email">Email：</label>
            <input type="text" id="email" class="form-control" value="${user.email}" 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" />
            <a class="btn btn-default" href="${pageContext.request.contextPath}/userListServlet">返回</a>
        </div>
    </form>
</div>
</body>
</html>

FindUserServlet

package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.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;

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

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

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

UpdateUserServlet

package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.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;

@WebServlet("/updateUserServlet")
public class UpdateUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.设置编码
        req.setCharacterEncoding("utf-8");
        //2.获取map
        Map<String, String[]> map = req.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
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }

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

测试

删除

思路

通过获取到对应的id即可到servlet中处理，操作数据库删除，在进行删除的时候可出现提示框

DelUserServlet

package cn.guizimo.little.web.servlet;

import cn.guizimo.little.service.UserService;
import cn.guizimo.little.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;

@WebServlet("/delUserServlet")
public class DelUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取id
        String id = req.getParameter("id");
        //2.调用service删除
        UserService service = new UserServiceImpl();
        service.deleteUser(id);

        //3.跳转到查询所有Servlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }

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

测试

删除选择的多个

思路

和删除差不多，最主要是获取id的集合

DelSelectedServlet

package cn.guizimo.little.web.servlet;

import cn.guizimo.little.service.UserService;
import cn.guizimo.little.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;

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

        //3.跳转查询所有Servlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }

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

测试

分页

思路

在jsp中获取查询的总条数，每页显示的条数，当前的页码，将之传递给服务器，操作数据库进行查询

list.jsp

<%--
  Created by IntelliJ IDEA.
  User: tanglei
  Date: 2020/6/28
  Time: 下午2:15
  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">
    <!-- 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。
     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>
    <script>
        function deleteUser(id) {
            //用户安全提示
            if (confirm("您确定要删除吗？")) {
                //访问路径
                location.href = "${pageContext.request.contextPath}/delUserServlet?id=" + id;
            }
        }

        window.onload = function () {
            //给删除选中按钮添加单击事件
            document.getElementById("delSelected").onclick = function () {
                if (confirm("您确定要删除选中条目吗？")) {
                    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++) {
                        if (cbs[i].checked) {
                            //有一个条目选中了
                            flag = true;
                            break;
                        }
                    }

                    if (flag) {//有条目被选中
                        //表单提交
                        document.getElementById("form").submit();
                    }
                }
            }
            //1.获取第一个cb
            document.getElementById("firstCb").onclick = function () {
                //2.获取下边列表中所有的cb
                var cbs = document.getElementsByName("uid");
                //3.遍历
                for (var i = 0; i < cbs.length; i++) {
                    //4.设置这些cbs[i]的checked状态 = firstCb.checked
                    cbs[i].checked = this.checked;
                }
            }
        }
    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>
    <div style="float: left;">

        <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="text" name="email" value="${condition.email[0]}" class="form-control"
                       id="exampleInputEmail2">
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp">添加联系人</a>
        <a class="btn btn-primary" href="javascript:void(0);" id="delSelected">删除选中</a>
    </div>
    <form id="form" action="${pageContext.request.contextPath}/delSelectedServlet" method="post">
        <table border="1" class="table table-bordered table-hover">
            <tr class="success">
                <th><input type="checkbox" id="firstCb"></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>

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

                <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]}">${i}</a>
                        </li>
                    </c:if>
                </c:forEach>
                <c:if test="${pb.currentPage == pb.totalPage}">
                    <li class="disabled">
                        <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.totalPage}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}"
                           aria-label="Next">
                            <span aria-hidden="true">&raquo;</span>
                        </a>
                    </li>
                </c:if>
                <c:if test="${pb.currentPage != pb.totalPage}">
                    <li>
                        <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>
                    </li>
                </c:if>

                <span style="font-size: 25px;margin-left: 5px;">
                    共${pb.totalCount}条记录，共${pb.totalPage}页
                </span>
            </ul>
        </nav>
    </div>

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

FindUserByPageServlet

package cn.guizimo.little.web.servlet;


import cn.guizimo.little.domain.PageBean;
import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.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;

@WebServlet("/findUserByPageServlet")
public class FindUserByPageServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");

        //1.获取参数
        String currentPage = request.getParameter("currentPage");//当前页码
        String rows = request.getParameter("rows");//每页显示条数

        if(currentPage == null || "".equals(currentPage)){
            currentPage = "1";
        }

        if(rows == null || "".equals(rows)){
            rows = "5";
        }
        
        //获取条件查询参数
        Map<String, String[]> condition = request.getParameterMap();

        //2.调用service查询
        UserService service = new UserServiceImpl();
        PageBean<User> pb = service.findUserByPage(currentPage,rows,condition);

        System.out.println(pb);

        //3.将PageBean存入request
        request.setAttribute("pb",pb);
        request.setAttribute("condition",condition);//将查询条件存入request
        //4.转发到list.jsp
        request.getRequestDispatcher("/list.jsp").forward(request,response);
    }

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

测试

条件查询

思路

主要是在sql语句的编写

jsp

<div style="float: left;">
        <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="${condition.address[0]}" class="form-control"
                       id="exampleInputName3">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">邮箱</label>
                <input type="text" name="email" value="${condition.email[0]}" class="form-control"
                       id="exampleInputEmail2">
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

dao层方法

@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 ? ");
                params.add("%"+value+"%");//？条件的值
            }
        }
        //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();
        System.out.println(sql);
        System.out.println(params);
        return template.query(sql,new BeanPropertyRowMapper<User>(User.class),params.toArray());
    }

测试

感谢

黑马程序员

万能的网络

以及勤劳的自己

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原文地址：https://www.cnblogs.com/guizimo/p/13209843.html