java后端：實現導出excel，按其中一個列的數據生成二維碼圖片，顯示在列表中

新手記錄自己的用過的工具，要是能幫到碼友就更好了。借鑒：（借鑒的文章找不到了）

 

需求分析：

實現導出excel，二維碼根據編號生成，二維碼圖片不存儲在數據庫(剛看到需求，還以為要把二維碼圖片存在數據庫，前輩說完全沒必要存)

　　

 

 

 

運行環境及框架： idea、springboot、

 

實現：

第一步：導入依賴

<!--zxing-->
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>javase</artifactId>
            <version>3.2.1</version>
        </dependency>
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>core</artifactId>
            <version>3.2.1</version>
        </dependency>
        <dependency>
            <groupId>org.jeecg</groupId>
            <artifactId>easypoi-base</artifactId>
            <version>2.3.1</version>
        </dependency>
        <!--zxing-->

 第二步：放在工具類

import com.google.zxing.BarcodeFormat;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;
import com.zkhb.boot.ponder.common.utils.common.QRCodeUtil;
import com.zkhb.boot.ponder.common.web.exception.PonderException;
import com.zkhb.boot.ponder.services.pound.entity.PoundCasualUser;
import com.zkhb.boot.ponder.services.pound.vo.report.PoundCasualUserReport;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.ss.usermodel.Workbook;
import org.jeecgframework.poi.excel.ExcelExportUtil;
import org.jeecgframework.poi.excel.entity.ExportParams;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

/**
 * @author Chen
 * @Description:
 * @ClassName:ExeclUtil
 * @date 2020/7/7 12:46
 * @Version: 1.0
 * @RETURN
 */
@Slf4j
public class ExcelUtil {
    /**
     * 導出excel
     *
     * @param response HttpServletResponse
     * @param fileName 文件名字
     * @param workbook 通過exportPicture()方法獲取
     * @author zhy
     */
    public static void writeExcel(HttpServletResponse response, String fileName, Workbook workbook) {
        // 判斷數據
        if (workbook == null) {
            throw new PonderException("錯誤");
        }
        // 重置響應對象
        response.reset();
        try {
            OutputStream outputStream = getOutputStream(fileName, response);
            BufferedOutputStream bufferedOutPut = new BufferedOutputStream(outputStream);
            workbook.write(bufferedOutPut);
            bufferedOutPut.flush();
            bufferedOutPut.close();
            outputStream.close();
        } catch (IOException e) {
            log.error(e.getMessage());
        }
    }

    /**
     * 導出文件時為Writer生成OutputStream
     *
     * @param fileName 文件名字
     * @param response response
     * @return 輸出流
     * @author zhy
     */
    private static OutputStream getOutputStream(String fileName, HttpServletResponse response) {
        try {
            fileName = URLEncoder.encode(fileName, "UTF-8");
            response.setContentType("application/vnd.ms-excel");
            response.setCharacterEncoding("utf8");
            response.setHeader("Content-Disposition", "attachment; filename=" + fileName + ".xls");
            response.setHeader("Pragma", "public");
            response.setHeader("Cache-Control", "no-store");
            response.addHeader("Cache-Control", "max-age=0");
            return response.getOutputStream();
        } catch (IOException e) {
            throw new PonderException("導出excel表格失敗!");
        }
    }

    /**
     * 獲取Workbook對象
     *
     * @param pigList     查詢黑豬對象列表
     * @param aesPassword aes加密密碼
     * @param qrCodeUrl   溯源網址前綴
     * @return 文件下載
     * @author zhy
     */
    public static Workbook exportPicture(List<PoundCasualUser> pigList, String aesPassword, String qrCodeUrl) {
        List<PoundCasualUserReport> list = new ArrayList<>();

        pigList.forEach(item -> {
            PoundCasualUserReport e = new PoundCasualUserReport();
            e.setTransportType(item.getTransportType()==0 ? "一車一貨":"一車多貨");
            e.setCardNo(item.getCardNo());
            String text=item.getCardNo();
            QRCodeWriter qrCodeWriter = new QRCodeWriter();
            BitMatrix bitMatrix = null;
            try {
                bitMatrix = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, 150, 150);
            } catch (WriterException e1) {
                e1.printStackTrace();
            }
            BufferedImage image = QRCodeUtil.toBufferedImage(bitMatrix);
            byte[] pngs = imageToBytes(image);
            e.setQrCode(pngs);
            list.add(e);
        });
        return ExcelExportUtil.exportExcel(new ExportParams(), PoundCasualUserReport.class, list);
    }

    /**
     * BufferedImage轉byte[]
     *
     * @param bImage BufferedImage對象
     * @return byte[]
     * @auth zhy
     */
    private static byte[] imageToBytes(BufferedImage bImage) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try {
            ImageIO.write(bImage, "png", out);
        } catch (IOException e) {
            log.error(e.getMessage());
        }
        return out.toByteArray();
    }

}

第三步：controller層 @ApiOperation("導出")    @RequestMapping(value = "/export")

public Result export( @RequestParam(value = "ids") @ApiParam(value = "要導出的id，多個用逗號隔開", required = true) String ids, HttpServletRequest request,HttpServletResponse response)throws Exception{
　　　　//獲取List集合（替換上你要導出的集合） List<PoundCasualUser> poundCasualUserList=poundCasualUserService.getCasualUserList(ids);
　　　　//導出的excel名 String fileName = "臨時用戶列表" + DateUtils.formatDate(new Date(), "yyyyMMddHHmmss");
　　　　//調用導出的方法 ExcelUtil.writeExcel(response,fileName,ExcelUtil.exportPicture(poundCasualUserList,null,null)); return null; }

效果：

用swagger調用接口，導出的沒有數據，但是前端調用的效果如下：（有大佬知道什么問題的話，望指教）