jsp+servlet 导出Excel表格

1.项目的目录结构

2.创建一个用户类，下面会通过查询数据库把数据封装成用户实例列表

package csh.entity;

/**
 * @author 悦文
 * @create 2018-10-24 18:41
 **/
public class Order {
    private int id;
    private String name;
    private int status;
    private String updatetime;

    public Order(int id, String name, int status, String updatetime) {
        this.id = id;
        this.name = name;
        this.status = status;
        this.updatetime = updatetime;
    }

    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 int getStatus() {
        return status;
    }

    public void setStatus(int status) {
        this.status = status;
    }

    public String getUpdatetime() {
        return updatetime;
    }

    public void setUpdatetime(String updatetime) {
        this.updatetime = updatetime;
    }
}

3.ExcelUtil.java文件,创建Excel基础类

package jdbc.dao;

import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.HorizontalAlignment;

/**
 * 创建Excel基础类
 *
 * @author 悦文
 * @create 2018-11-15 10:07
 **/
public class ExcelUtil {
    public static HSSFWorkbook getHSSFWorkbook(String sheetName, String[] title, String[][] values, HSSFWorkbook wb) {

        // 第一步，创建一个HSSFWorkbook，对应一个Excel文件
        if (wb == null) {
            wb = new HSSFWorkbook();
        }

        // 第二步，在workbook中添加一个sheet,对应Excel文件中的sheet
        HSSFSheet sheet = wb.createSheet(sheetName);

        // 第三步，在sheet中添加表头第0行,注意老版本poi对Excel的行数列数有限制
        HSSFRow row = sheet.createRow(0);

        // 第四步，创建单元格，并设置值表头 设置表头居中
        HSSFCellStyle style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.CENTER); // 创建一个居中格式

        //声明列对象
        HSSFCell cell = null;

        //创建标题
        for (int i = 0; i < title.length; i++) {
            cell = row.createCell(i);
            cell.setCellValue(title[i]);
            cell.setCellStyle(style);
        }

        //创建内容
        for (int i = 0; i < values.length; i++) {
            row = sheet.createRow(i + 1);
            for (int j = 0; j < values[i].length; j++) {
                //将内容按顺序赋给对应的列对象
                row.createCell(j).setCellValue(values[i][j]);
            }
        }
        return wb;
    }
}

4.查询数据库得到导出的数据

public static List<Order> getOrderByDate(String start, String end, int currentpage, int maximum) throws SQLException {
        //int id = -1;
        try {
            //HH:mm:ss:SSS
            //currentpage=currentpage-1;
            //分页起始点
            int maximumstart = maximum * (currentpage - 1);
            Long startstamp = Timestamp.dateToStamp(start + ":000");
            Long endstamp = Timestamp.dateToStamp(end + ":000");
            Connection conn = Dao.getConnection();
            //select * from order_user WHERE update_time BETWEEN 1541001600000 AND 1543507200000 GROUP BY update_time DESC limit 0,2 ;
            PreparedStatement ps = (PreparedStatement) conn
                    .prepareStatement("select * from order_user WHERE update_time BETWEEN ? AND ? GROUP BY id DESC  limit " + maximumstart + "," + maximum);
            ps.setLong(1, startstamp);
            ps.setLong(2, endstamp);
//            ps.setInt(3, Integer.parseInt(contrller));
            // ps.setString(1, name);
            ResultSet rs = ps.executeQuery();
            List<Order> orderlist = new ArrayList();
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                int status = rs.getInt("status");
                long updatetime = rs.getLong("update_time");
                String updatetimes = String.valueOf(updatetime);
                Order order = new Order(id, name, status, Timestamp.stampToDate(updatetimes));
                orderlist.add(order);
            }
            Dao.close(rs, ps, conn);
            return orderlist;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }

5.ExportExcelServlet.java,创建Excel响应流

package com.csh.servlet;

import csh.entity.Order;
import jdbc.dao.ExcelUtil;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import search.SearchDao;

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.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.List;
import java.util.Map;

/**
 * Created by admin on 2018/11/16.
 */
@WebServlet(name = "ExportExcelServlet")
public class ExportExcelServlet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String start = "";
        String end = "";
        String contrller = "";
        String uri = request.getRequestURL() + (request.getQueryString() != null ? "?" + request.getQueryString() : "");
        System.out.println(uri);
        Map<String, String[]> querymap = request.getParameterMap();

        //判断不为空
        for (String key : querymap.keySet()) {
            String t = querymap.get(key)[0];
            if (key.equals("startdate")) {
                if (!t.equals("")) {
                    start = querymap.get(key)[0];
                }
            } else if (key.equals("startend")) {
                if (!t.equals("")) {
                    end = querymap.get(key)[0];
                }

            } else if (key.equals("contrller")) {
                if (!t.equals("")) {
                    contrller = querymap.get(key)[0];
                }
            }
        }

        if (start.equals("") || end.equals("") || start.equals("null") || end.equals("null")) {
            //判断时间为空且状态为空
            if (contrller.equals("") || contrller.equals("null")) {
                try {
                    export(request, response,SearchDao.getAll());
                } catch (Exception e) {
                    e.printStackTrace();
                }
                //判断时间为空但是状态不为空
            } else {
                try {
                    export(request, response,SearchDao.exportOrderByStatus(contrller));
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        } else {
            //判断时间不为空且状态不为空
            if (!contrller.equals("") && !contrller.equals("null")) {
                try {
                    export(request, response,SearchDao.exportOrderByDateAndContrller(start, end, contrller));
                } catch (Exception e) {
                    e.printStackTrace();
                }
            } else {
                //判断时间不为空，状态为空
                try {
                    export(request, response,SearchDao.exportOrderByDate(start, end));
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }

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

    public void export(HttpServletRequest request, HttpServletResponse response,List<Order> order) throws Exception {
        //获取数据
        List<Order> list = order;

        //excel标题
        String[] title = {"ID", "name", "status", "update_time", "comment"};

        //excel文件名
        String fileName = "订餐统计表" + System.currentTimeMillis() + ".xls";

        //sheet名
        String sheetName = "订餐统计";

        String[][] content=new String[list.size()][title.length];
        for (int i = 0; i < list.size(); i++) {
            content[i] = new String[title.length];
            Order obj = list.get(i);
            content[i][0] = String.valueOf(obj.getId());
            content[i][1] = obj.getName();
            if(obj.getStatus()==1){
                content[i][2] = "加班已订餐";
            }else if(obj.getStatus()==2){
                content[i][2] = "加班未订餐";
            }
            //content[i][2] = String.valueOf(obj.getStatus());
            content[i][3] = obj.getUpdatetime();
            //content[i][4] = obj.get("comment").tostring();
        }

//------------------------以下是向excel中导入查询的数据----------------------
//创建HSSFWorkbook
        HSSFWorkbook wb = ExcelUtil.getHSSFWorkbook(sheetName, title, content, null);

//响应到客户端
        try {
            this.setResponseHeader(response, fileName);
            OutputStream os = response.getOutputStream();
            wb.write(os);
            os.flush();
            os.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //发送响应流方法
    public void setResponseHeader(HttpServletResponse response, String fileName) {
        try {
            try {
                fileName = new String(fileName.getBytes(), "ISO8859-1");
            } catch (UnsupportedEncodingException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            response.setContentType("application/octet-stream;charset=ISO8859-1");
            response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
            response.addHeader("Pargam", "no-cache");
            response.addHeader("Cache-Control", "no-cache");
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

6.请求页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <meta charset="UTF-8">
    <title>欢迎页面-X-admin2.0</title>
    <meta name="renderer" content="webkit">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <meta name="viewport"
          content="width=device-width,user-scalable=yes, minimum-scale=0.4, initial-scale=0.8,target-densitydpi=low-dpi"/>
    <link rel="shortcut icon" href="/favicon.ico" type="image/x-icon"/>
    <link rel="stylesheet" href="./css/font.css">
    <link rel="stylesheet" href="./css/xadmin.css">
    <script type="text/javascript" src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
    <script type="text/javascript" src="./lib/layui/layui.js" charset="utf-8"></script>
    <script type="text/javascript" src="./js/xadmin.js"></script>
    <!-- 让IE8/9支持媒体查询，从而兼容栅格 -->
    <!--[if lt IE 9]>
    <script src="https://cdn.staticfile.org/html5shiv/r29/html5.min.js"></script>
    <script src="https://cdn.staticfile.org/respond.js/1.4.2/respond.min.js"></script>
    <![endif]-->
</head>

<body>
   <xblock>
        <button class="layui-btn layui-btn-danger" onclick="exporExcel()">导出Excel</button>
    </xblock>

<script>
    function exporExcel() {
        var obj = document.getElementById("contrller"); //定位id
        var index = obj.selectedIndex; // 选中索引
        //var text = obj.options[index].text; // 选中文本
        var contrller = obj.options[index].value; // 选中值
        var startdate = document.getElementById("start").value;
        var startend = document.getElementById("end").value;

        window.location.href = "/javawebservlet/ExportExcelServlet?startdate="+startdate+"&"+"startend="+startend+"&"+"contrller="+contrller;
    }
</script>

</body>

</html>