JAVA将数据库数据导出为Excel

前注：来源于网络

描述：客户端通过HTTP的GET方式请求，在后台处理并从数据库中查询到数据列表，最终将数据列表生成HTTP相应流返回到客户端，客户端即实现对数据的Excel导出。

1. 依赖

<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.6</version>
</dependency>

2. 工具类

package com.xfc.util;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

/**
 * @Auther: xfc
 * @Date: 2019/5/20 0020 14:21
 * @Description:
 */
public class ExcelUtil {

    /**
     * 导出Excel
     *
     * @param sheetName sheet名称
     * @param title     标题
     * @param values    内容
     * @param wb        HSSFWorkbook对象
     * @return
     */
    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(HSSFCellStyle.ALIGN_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;
    }
}

3. 调用

因为业务简单，我这里在controller层就直接处理了

    /**
     * 根据条件将数据导出为Excel
     * 如果需要浏览器发送请求时即下载Excel，就不能用ajax进行传输，所以这里用GET方式进行提交
     *
     * @return
     */
    @ResponseBody
    @RequestMapping(value = "/exportExcel", method = RequestMethod.GET)
    public void exportExcel(HttpServletRequest request, HttpServletResponse response) {
        QRRecord obj = new QRRecord();
        obj.setPageStart(Integer.valueOf(request.getParameter("pageStart")));
        obj.setPageSize(Integer.valueOf(request.getParameter("pageSize")));
        obj.setTerm(request.getParameter("term"));
        List<QRRecord> list = qrRecordService.findQRRecordList(obj);
        String[] title = {"ID", "业主姓名", "识别时间", "设备名称", "识别位置", "目的楼层", "备注信息"};
        String filename = "QRCodeRecord.xls";
        String sheetName = "sheet1";
        String[][] content = new String[list.size()][7];
        try {
            for (int i = 0; i < list.size(); i++) {
                content[i][0] = String.valueOf(list.get(i).getRid());
                content[i][1] = list.get(i).getOwnerName();
                content[i][2] = list.get(i).getAddTime();
                content[i][3] = list.get(i).getDeviceName();
                content[i][4] = list.get(i).getLocation();
                content[i][5] = String.valueOf(list.get(i).getAimFloor());
                content[i][6] = list.get(i).getDescription();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        HSSFWorkbook wb = ExcelUtil.getHSSFWorkbook(sheetName, title, content, null);
        try {
            // 响应到客户端
            this.setResponseHeader(response, filename);
            OutputStream os = response.getOutputStream();
            wb.write(os);
            os.flush();
            os.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 向客户端发送响应流方法
     *
     * @param response
     * @param fileName
     */
    public void setResponseHeader(HttpServletResponse response, String fileName) {
        try {
            try {
                fileName = new String(fileName.getBytes(), "UTF-8");
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            response.setContentType("application/vnd.ms-excel");
            response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

4. JS调用

let url = "localhost:808//.../.../exportExcel?pageStart=0&pageSize=50";
location.href = url;

5. 成功后，即通过浏览器进行下载

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