java 导出百万数据到excel

@RequestMapping("export")
        public void write(HttpServletRequest request,HttpServletResponse response,String agent,String starttime,
                        String endtime,int callduration,String dst,String answer) {
                try {
                        Map<String,Object> param = new HashMap<>();
                        User user = (User) request.getSession().getAttribute(Constant.LOGIN_USER);
                        param.put("agent", agent);
                        param.put("starttime", starttime == "" ? DateUtil.getFirstDayByMonth() : starttime);
                        param.put("endtime", endtime == "" ? DateUtil.getLastDayByMonth() : endtime);
                        param.put("callduration", callduration);
                        param.put("dst",dst);
                        param.put("answer",answer);
                        if(DateUtil.isThisMonth(param.get("starttime").toString()) && DateUtil.isThisMonth(param.get("endtime").toString())){
                                param.put("cdr", "cdr"+user.getPbxid());
                        }else{
                                param.put("cdr", "cdr"+user.getPbxid()+"_"+DateUtil.getYearAndMonth(param.get("starttime").toString()));
                        }
                        // 创建CSV写对象  查询数据
                        List<Map<String, Object>> list = this.cdrService.listCdrs(param);
                        // 写入临时文件
                        File tempFile = File.createTempFile("vehicle", ".csv");
                        CsvWriter csvWriter = new CsvWriter(tempFile.getCanonicalPath(), ',', Charset.forName("UTF-8"));
                        // 写表头
                        String headers[] = new String[]{"id", "主叫", "被叫", "开始时间", "应答时间", "结束时间", "总时长(秒)", "通话时长(秒)", "通话状态","挂断方"};
                        csvWriter.writeRecord(headers);
                        for(int i = 0;i<list.size();i++){
                                csvWriter.write(list.get(i).get("clid").toString()==null? "" :list.get(i).get("clid").toString());
                                csvWriter.write(list.get(i).get("src").toString()==null? "" :list.get(i).get("src").toString());
                                csvWriter.write(list.get(i).get("dst").toString()==null? "" :list.get(i).get("dst").toString());
                                csvWriter.write(list.get(i).get("start").toString()==null? "" :list.get(i).get("start").toString());
                                csvWriter.write(list.get(i).get("answer").toString()==null? "" :list.get(i).get("answer").toString());
                                csvWriter.write(list.get(i).get("end").toString()==null? "" :list.get(i).get("end").toString());
                                Integer billsec = Integer.parseInt(list.get(i).get("billsec").toString());
                                Integer duration =  Integer.parseInt(list.get(i).get("duration").toString());
                                csvWriter.write(String.valueOf(billsec+duration));
                                csvWriter.write(list.get(i).get("billsec").toString()==null? "" :list.get(i).get("billsec").toString());
                                String disposition = list.get(i).get("disposition").toString();
                                        if (disposition.equals("ANSWERED")) {
                                                csvWriter.write("已接通");
                                        } else if (disposition.equals("NO ANSWER")) {
                                                csvWriter.write("未接通");
                                        } else if (disposition.equals("BUSY")) {
                                                csvWriter.write("忙碌");
                                        } else if (disposition.equals("FILED")) {
                                                csvWriter.write("失败");
                                        } else {
                                                csvWriter.write("");
                                        }
                                        String hanger = list.get(i).get("hanger").toString();
                                        if (Integer.parseInt(hanger)==-1) {
                                                csvWriter.write("客户挂断");
                                        } else {
                                                csvWriter.write("坐席挂断");
                                        }
                                csvWriter.endRecord();
                        }
                        csvWriter.close();
                        /**
                         * 写入csv结束，写出流
                         */
                        java.io.OutputStream out = response.getOutputStream();
                        byte[] b = new byte[10240];
                        java.io.File fileLoad = new java.io.File(tempFile.getCanonicalPath());
                        response.setContentType("application/csv");
                        response.setHeader("content-disposition", "attachment; filename="+ DateUtil.getDate()+".csv");
 　　　　　　　　　　　　　　out.write("\ufeff".getBytes());
                        long fileLength = fileLoad.length();
                        String length1 = String.valueOf(fileLength);
                        response.setHeader("Content_Length", length1);
                        java.io.FileInputStream in = new java.io.FileInputStream(fileLoad);
                        int n;
                        while ((n = in.read(b)) != -1) {
                                out.write(b, 0, n); // 每次写入out1024字节
                        }
                        in.close();
                        out.close();

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

　　注意：如果是数字类型太长超过16位写入到excel会丢失

　　解决办法 将 csvWriter.write 改成 csvWriter.writeRecord()

把长数字转换成字符串，并在输在字符串前面增加“\t”。

例如：

String un = list.get(i).get("uniqueid").toString().replaceFirst("#", "");
                                        String[] u = new String[]{"\t"+un};
                                        csvWriter.writeRecord(u,true);