springboot中文件下载【完整代码】

一、概述
企业开发中，文件的导出基本是每个项目都会涉及到的，虽然网络上也有很多大神总结的导出POI的代码，但是感觉写的都比较乱，基于此本文从前端到后台完整演示文件导出是如何实现的。供广大IT爱好者参考。
说明：本项目是在学习尚硅谷-雷丰阳老师的springboot整合web时，做的一个springboot-restful-crud的整合项目，在此感谢尚硅谷的雷老师！视频地址：https://www.bilibili.com/video/BV1Et411Y7tQ?from=search&seid=3721447562465164009
1、先看效果图
在这里插入图片描述 2、Excel表格中的数据

3、上代码
（1）前端代码

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">

	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
		<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
		<meta name="description" content="">
		<meta name="author" content="">

		<title>Dashboard Template for Bootstrap</title>
		<!-- Bootstrap core CSS -->
		<link th:href="@{/asserts/css/bootstrap.min.css}" rel="stylesheet">

		<!-- Custom styles for this template -->
		<link th:href="@{/asserts/css/dashboard.css}" rel="stylesheet">
		<style type="text/css">
			/* Chart.js */
			
			@-webkit-keyframes chartjs-render-animation {
     
     
				from {
     
     
					opacity: 0.99
				}
				to {
     
     
					opacity: 1
				}
			}
			
			@keyframes chartjs-render-animation {
     
     
				from {
     
     
					opacity: 0.99
				}
				to {
     
     
					opacity: 1
				}
			}
			
			.chartjs-render-monitor {
     
     
				-webkit-animation: chartjs-render-animation 0.001s;
				animation: chartjs-render-animation 0.001s;
			}
		</style>
	</head>

	<body>
		<!--
			引入顶部栏
			语法：th:replace="~{模板名::片段名}"
				 th:replace="模板名::片段名"
		-->
		<div th:replace="commons/commonbar::topbar"></div>

		<div class="container-fluid">
			<div class="row">
				<!--
					引入侧边栏
						语法：th:replace="~{模板名::片段名}"
				 			 th:replace="模板名::片段名"
				-->
				<div th:replace="commons/commonbar::sidebar(activeUri='department/getAllDepartments')"></div>

				<main role="main" class="col-md-9 ml-sm-auto col-lg-10 pt-3 px-4">
					<h2>
						<a class="btn btn-sm btn-success" th:href="@{/department/toDepartmentAddPage}">添加</a>
						<a class="btn btn-sm btn-success" th:href="@{/employee/toImportExcelPage}">导入</a><!--TODO-->
						<a class="btn btn-sm btn-success" th:href="@{/department/exportDepartment}">导出</a>
						<a class="btn btn-sm btn-success" th:href="@{/employee/batchDeleteEmployee}">批量删除</a><!--TODO-->
					</h2>
					<div class="table-responsive">
						<table class="table table-striped table-sm">
							<thead>
								<tr>
									<th>部门编号</th>
									<th>部门名称</th>
									<th>操作</th>
								</tr>
							</thead>
							<tbody>
								<tr th:each="department:${departments}">
									<td th:text="${department.id}"></td>
									<td th:text="${department.departmentName}"></td>
									<td>
										<a class="btn btn-sm btn-primary" th:href="@{/department/toDepartmentEditPage/}+${department.id}">编辑</a>
										<button th:attr="delUri=@{/department/deleteDepartmentById/}+${department.id}"  class="btn btn-sm btn-danger delBtn">删除</button>
									</td>
								</tr>
							</tbody>
						</table>
					</div>
				</main>
			</div>
		</div>

		<!-- Bootstrap core JavaScript
    ================================================== -->
		<!-- Placed at the end of the document so the pages load faster -->
		<script type="text/javascript" th:src="@{/asserts/js/jquery-3.2.1.slim.min.js}"></script>
		<script type="text/javascript" th:src="@{/asserts/js/popper.min.js}"></script>
		<script type="text/javascript" th:src="@{/asserts/js/bootstrap.min.js}"></script>

		<!-- Icons -->
		<script type="text/javascript" th:src="@{/asserts/js/feather.min.js}"></script>
		<script>
			feather.replace()
		</script>

		<!-- Graphs -->
		<script type="text/javascript" th:src="@{/asserts/js/Chart.min.js}"></script>
		<script>
			var ctx = document.getElementById("myChart");
			var myChart = new Chart(ctx, {
     
     
				type: 'line',
				data: {
     
     
					labels: ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"],
					datasets: [{
     
     
						data: [15339, 21345, 18483, 24003, 23489, 24092, 12034],
						lineTension: 0,
						backgroundColor: 'transparent',
						borderColor: '#007bff',
						borderWidth: 4,
						pointBackgroundColor: '#007bff'
					}]
				},
				options: {
     
     
					scales: {
     
     
						yAxes: [{
     
     
							ticks: {
     
     
								beginAtZero: false
							}
						}]
					},
					legend: {
     
     
						display: false,
					}
				}
			});
		</script>
	</body>
</html>

（2）DepartmentController

@Controller
public class DepartmentController {
    
    
    Logger logger = LoggerFactory.getLogger(getClass());
    @Resource
    private DepartmentService departmentService;
    
    //导出
    @GetMapping(value = "/department/exportDepartment")
    public void exportDepartment(HttpServletResponse response) {
    
    
        try {
    
    
            response.setContentType("application/binary;charset=UTF-8");
            ServletOutputStream outputStream = response.getOutputStream();
            SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmsssSSS");
            String fileName = URLEncoder.encode("部门统计表"+sdf.format(new Date()), "UTF-8");
            response.setHeader("Content-disposition", "attachment; filename=" + fileName + ".xls");
            String[] titles = {
    
     "部门编号", "部门名称"};
            departmentService.exportDepartment(titles,outputStream);
        } catch (IOException e) {
    
    
            e.printStackTrace();
        }
    }
}

（3）DepartmentService

package com.atguigu.springboot.service;

import com.atguigu.springboot.pojo.Department;

import javax.servlet.ServletOutputStream;
import java.util.List;

public interface DepartmentService {
    
    
    /**
     * 导出xls格式的Excel
     * @param titles
     * @param outputStream
     */
    void exportDepartment(String[] titles, ServletOutputStream outputStream);
}

（4）DepartmentServiceImpl

package com.atguigu.springboot.service.impl;

import com.atguigu.springboot.mapper.DepartmentMapper;
import com.atguigu.springboot.pojo.Department;
import com.atguigu.springboot.service.DepartmentService;
import com.atguigu.springboot.utils.PoiXlsStyleUtils;
import javafx.scene.control.Cell;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.CellStyle;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;

import javax.annotation.Resource;
import javax.servlet.ServletOutputStream;
import java.io.IOException;
import java.util.Collections;
import java.util.List;

@Service
public class DepartmentServiceImpl implements DepartmentService {
    
    
    @Resource
    private DepartmentMapper departmentDao;

    @Override
    public void exportDepartment(String[] titles, ServletOutputStream outputStream) {
    
    
        //1、创建工作薄
        HSSFWorkbook workbook = new HSSFWorkbook();

        //2、创建工作表
        HSSFSheet sheet = workbook.createSheet("部门统计表");

        //3、创建一个行，当做标题行
        HSSFRow headerRow = sheet.createRow(0);

        //4、表头样式
        CellStyle headerCellStyle = PoiXlsStyleUtils.getHeaderCellStyle(workbook);
        HSSFCell cell = null;
        for(int i=0; i<titles.length; i++){
    
    
            cell = headerRow.createCell(i);            //第1行第i列
            cell.setCellValue(titles[i]);              //第1行第i列填充值
            cell.setCellStyle(headerCellStyle);        //居中显示
        }

        //5、写入数据
        //内容样式
        CellStyle contentCellStyle = PoiXlsStyleUtils.getContentCellStyle(workbook);
        List<Department> departments = departmentDao.getAllDepartments();
        if(!CollectionUtils.isEmpty(departments)){
    
    
            for(int i=0; i<departments.size(); i++){
    
    
                HSSFRow row = sheet.createRow(i + 1);   							//第i+1行,从第二行开始

                Department department = departments.get(i);

                HSSFCell cellId = row.createCell(0);    							//部门编号cell
                cellId.setCellValue(department.getId());       						//设置部门编号
                cellId.setCellStyle(contentCellStyle);         						//部门编号设置样式

                HSSFCell cellDepartmentname = row.createCell(1);					//部门名称cell
                cellDepartmentname.setCellValue(department.getDepartmentName());	//设置部门名称
                cellDepartmentname.setCellStyle(contentCellStyle);					//部门名称设置样式
            }
        }

        //6、下载文件
        try {
    
    
            workbook.write(outputStream);
            outputStream.flush();

            outputStream.close();
            workbook.close();

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

（4）PoiXlsStyleUtils

package com.atguigu.springboot.utils;

import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

/**
 * xls版本的样式设置工具类
 */
public class PoiXlsStyleUtils {
    
    
    //设置表头样式
    public static CellStyle getHeaderCellStyle(HSSFWorkbook workbook){
    
    
        HSSFCellStyle cellStyle = workbook.createCellStyle();
        cellStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());    //前景色
        cellStyle.setFillPattern(CellStyle.SOLID_FOREGROUND);               //线条
        cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);                 //居中设置

        //设置边框
        cellStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN);               //下边框
        cellStyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);                 //左边框
        cellStyle.setBorderTop(HSSFCellStyle.BORDER_THIN);                  //上边框
        cellStyle.setBorderRight(HSSFCellStyle.BORDER_THIN);                //右边框

        return cellStyle;
    }

    //设置内容样式
    public static CellStyle getContentCellStyle(HSSFWorkbook workbook){
    
    
        HSSFCellStyle cellStyle = workbook.createCellStyle();
        cellStyle.setAlignment(HSSFCellStyle.ALIGN_LEFT);                   //内容左对齐

        //设置边框
        cellStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN);               //下边框
        cellStyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);                 //左边框
        cellStyle.setBorderTop(HSSFCellStyle.BORDER_THIN);                  //上边框
        cellStyle.setBorderRight(HSSFCellStyle.BORDER_THIN);                //右边框
        return cellStyle;
    }
}

（5）DepartmentMapper

package com.atguigu.springboot.mapper;

import com.atguigu.springboot.pojo.Department;

import java.util.List;

public interface DepartmentMapper {
    
    
    /**
     * 查询所有的部门
     * @return
     */
    List<Department> getAllDepartments();

    /**
     * 添加部门
     * @param department
     */
    void saveDepartment(Department department);

    /**
     * 根据id查询部门
     * @param id
     * @return
     */
    Department getDepartmentById(Integer id);

    /**
     * 修改部门
     * @param department
     */
    void updateDepartment(Department department);
}

（6）DepartmentMapper.xml

<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.atguigu.springboot.mapper.DepartmentMapper">

    <!--查询所有的部门-->
    <select id="getAllDepartments" resultType="department">
        select * from department
    </select>

    <!--添加部门-->
    <insert id="saveDepartment" parameterType="department">
        insert into department(id,department_name) values (#{id},#{departmentName})
    </insert>

    <!--根据id查询部门-->
    <select id="getDepartmentById" resultType="department">
        select * from department where id = #{id}
    </select>

    <!--修改部门-->
    <update id="updateDepartment">
        update department set department_name = #{departmentName} where id = #{id}
    </update>
</mapper>

	以上就是springboot中如何使用poi导出数据到Excel中，文档中的代码经过我自己测试验证，可以正常实现导出。学无止境，祝各位在IT的知识海洋里自由地遨游！如果你在学习过程中，遇到问题了，可以在评论区留言，我看到后会第一时间进行回复。

springboot中文件下载【完整代码】

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