导出Csv格式文件工具类

快来打我* 2022-01-23 02:43 347阅读 0赞

# 导出Csv格式文件工具类 #

项目中如果数据量大的情况下可以选择导出csv格式

## 1工具类 ##

**CsvUtils**

import javax.servlet.ServletOutputStream;
    import javax.servlet.http.HttpServletResponse;
    import java.io.*;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    import java.util.List;
    
    public class CsvUtils {
        /**
         * CSV文件生成方法
         *
         * @param head
         * @param dataList
         * @param filename
         * @return
         */
        public static File createCSVFile(List<Object> head, List<List<Object>> dataList,
                                         String filename) {
    
            File csvFile = null;
            BufferedWriter csvWriter = null;
            try {
                String path = System.getProperty("java.io.tmpdir");
                csvFile = new File(path + File.separator + filename + ".csv");
                File parent = csvFile.getParentFile();
                if (parent != null && !parent.exists()) {
                    parent.mkdirs();
                }
                csvFile.createNewFile();
    
                // GB2312使正确读取分隔符","
                csvWriter = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(
                        csvFile), "GB2312"), 1024);
                // 写入文件头部
                writeRow(head, csvWriter);
    
                // 写入文件内容
                for (List<Object> row : dataList) {
                    writeRow(row, csvWriter);
                }
                csvWriter.flush();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    csvWriter.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return csvFile;
        }
    
        /**
         * 写一行数据方法
         *
         * @param row
         * @param csvWriter
         * @throws IOException
         */
        private static void writeRow(List<Object> row, BufferedWriter csvWriter) throws IOException {
            // 写入文件头部
            for (Object data : row) {
                StringBuffer sb = new StringBuffer();
                String rowStr = sb.append("\"").append(data).append("\",").toString();
                csvWriter.write(rowStr);
            }
            csvWriter.newLine();
        }
    
        public static void toExport(List<Object> csvHeader, List<List<Object>> dataList,
                                    HttpServletResponse httpServletResponse) throws IOException {
    
            String fileName = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date()) + ".csv";
            String path = System.getProperty("java.io.tmpdir") + "\\" + fileName;
            File file = CsvUtils.createCSVFile(csvHeader, dataList, fileName);
            CsvUtils.toResponse(httpServletResponse, file, fileName);
        }
    
        public static void toResponse(HttpServletResponse httpServletResponse, File file, String fileName) throws IOException {
            BufferedInputStream bis = null;
            ServletOutputStream out = null;
    
            bis = new BufferedInputStream(new FileInputStream(file));
            out = httpServletResponse.getOutputStream();
            try {
                httpServletResponse.setContentType("application/octet-stream");
                httpServletResponse.addHeader("Content-Disposition", "attachment; filename=" + fileName);
                byte[] buff = new byte[1024];
                int bytesRead = 0;
                while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
                    out.write(buff, 0, bytesRead);
                }
            } finally {
                bis.close();
                out.close();
                if (file.exists()) {
                    file.delete();
                }
            }
        }
    }

## 2 用法记录 ##

@Override
        public void exportRecord(RecordParams params, HttpServletResponse response) throws IOException {
            Object[] csvHeader = {"农场名称", "地块名称", "作物", "批次", "农事环节", "农事时间", "记录时间", "总得分", "扣分原因"};
    		//需要导出的数据集合
            List<RecordDTO> list = this.recordService.listAllRecord(params);
            //头信息
            List<Object> headerList = Arrays.asList(csvHeader);
            //最终数据
            List<List<Object>> resultDataList = new ArrayList<>();
    
            if (CollectionUtils.isNotEmpty(list)) {
    
                for (RecordDTO record : list) {
                    Date updateTime = record.getUpdateTime();
    
                    Integer score = record.getScore();
                    Integer deductMarks = record.getDeductMarks();
                    Integer totalScore = score - deductMarks;
    
                    String reason = record.getReason();
                    String content =  reason + "\t";
    
                    Object[] accountProfitArray = new Object[csvHeader.length];
                    accountProfitArray[0] = record.getFarmName();
                    accountProfitArray[1] = record.getPlotName();
                    accountProfitArray[2] = record.getCropName();
                    accountProfitArray[3] = record.getCropVariety();
                    accountProfitArray[4] = record.getFarmWorkName();
                    accountProfitArray[5] = record.getTime() == null ? "" : DATE_FORMAT.format(record.getTime()) + "\t";
                    accountProfitArray[6] = updateTime == null ? "" : DATE_FORMAT.format(updateTime) + "\t";
                    accountProfitArray[7] = totalScore;
                    accountProfitArray[8] = content;
                    resultDataList.add(Arrays.asList(accountProfitArray));
    
                }
                CsvUtils.toExport(headerList, resultDataList, response);
    
            }
        }