java 生成excel表传给前端下载

js部分：

        var jsonstr=getSearchSel(os);        var str = "";//传参数        for(var i in jsonstr){            if(jsonstr[i]!=""){                str += i+"="+jsonstr[i]+"&";            }        }        str = str.substr(0, str.length - 1);         var url = "/QAdevices/ExcelServlet?" + str;        window.open(url);

java端：

 public void doGet(HttpServletRequest request, HttpServletResponse response)      throws ServletException, IOException {  StringBuilder jsonstr = new StringBuilder();//转化成json  jsonstr.append("{");  String reqstr = request.getQueryString();//获取请求参数  if(!"".equals(reqstr) &&reqstr !=null){  String [] stringArr= reqstr.split("&");  for(int i = 0;i<stringArr.length;i++){  String [] strArr = stringArr[i].split("=");   jsonstr.append("\""+strArr[0]+"\":"+"\""+strArr[1]+"\""+",") ;   }  jsonstr.deleteCharAt(jsonstr.length()-1);  }  jsonstr.append("}");  String filename =getExcelPath() ;  List<Map<String, Object>> searchlist = ServerInit.managerAction.searchDeviceInfoByConditions3(jsonstr.toString());  if(searchlist!=null){  HSSFWorkbook wb = createExcel(searchlist);   try{ //写入浏览器        response.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(filename, "UTF-8"));        OutputStream outputStream=response.getOutputStream();        wb.write(outputStream);        outputStream.flush();        outputStream.close();        }catch(Exception e){        logger.error("Exception",e);        }  }  }

/**     *  返回excel表生成的路径 *  参数   *  os,devicestatue，peopleId * @return excel表的服务器存储地址 * */public String getExcelPath() {//String str = this.getServletContext().getRealPath("/WEB-INF");  List<Map<String, Object>> searchlist = null;SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式String timestr = df.format(new Date()).toString().replace(" ", "-");timestr = timestr.replace(":","");String filename = "设备一览表-"+ timestr+".xls";logger.info("下载:"+filename);return filename;}/**     *  创建excel表 *  参数   *  数据库查询数据list，存储路径 * @return boolean true:生成成功  false: 生成失败 * @throws   * */public HSSFWorkbook createExcel(List<Map<String, Object>> list) {boolean bool = true;// 第一步，创建一个webbook，对应一个Excel文件 //XSSFWorkbook  wb = new XSSFWorkbook();        HSSFWorkbook wb = new HSSFWorkbook();          // 第二步，在webbook中添加一个sheet,对应Excel文件中的sheet          HSSFSheet sheet = wb.createSheet("设备信息");          // 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short          HSSFRow row = sheet.createRow((int) 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          ArrayList<String> title = new ArrayList<>(Arrays.asList("编号","设备编号","品牌名称","品牌","系统","系统版本","cpu","cpu型号","内存大小","屏幕尺寸","分辨率高","分辨率宽","imei1","imei2","sn","是否越狱","颜色","前置摄像头","后置摄像头","数据线","充电器","耳机","电池","手机壳","入库时间","设备管理员","借用人","状态","备注"));        //  System.out.println(title.size());        HSSFCell cell;        for(int i = 0 ;i<title.size();i++){        cell = row.createCell((short) i);        cell.setCellValue(title.get(i));        }        HSSFRow row1 = sheet.createRow((int) 1);         ArrayList<String> title2 = new ArrayList<>(Arrays.asList("必填","必填","必填","必填","android/ios","必填","厂商","厂商+型号","","","","","必填","","","0=否，1=是","","单位万","单位万","0=否，1=是","0=否，1=是","0=否，1=是","0=否，1=是","0=否，1=是","","","","状态(0完好 1破损 2老旧 3待修复 4已坏)",""));       // System.out.println(title2.size());        for(int i = 0 ;i<title2.size();i++){        cell = row1.createCell((short) i);        cell.setCellValue(title2.get(i));        }        HSSFRow row2;         HSSFCell cell2;                int i = 0;        int j = 0;        for (Map<String, Object> map : list) {//填充数据        row2 = sheet.createRow((int) i+2);         List<String> datalist = getData(map);        for( j = 0 ;j<datalist.size();j++){        cell2 = row2.createCell((short) j);        cell2.setCellValue(datalist.get(j));        }        i++;        }                        return wb;}/**     *  处理数据库查询出的数据，按照excel 列的顺序 *  参数   *  Map<String , Object>一行数据 * @return datalist * */public List<String> getData(Map<String, Object> map){List<String> stringList = new ArrayList<String>();for(Map.Entry<String,Object> entry : map.entrySet()){if(entry.getValue() == null){entry.setValue("");}if(entry.getValue() instanceof Boolean){//false:0 true:1if((Boolean)entry.getValue()){entry.setValue(1);}else {entry.setValue(0);}}}stringList.add(map.get("deviceid").toString());stringList.add(map.get("tag").toString());stringList.add(map.get("model").toString());stringList.add(map.get("brand").toString());stringList.add(map.get("os").toString());stringList.add(map.get("osversion").toString());stringList.add(map.get("cpu").toString());stringList.add(map.get("cpumodel").toString());stringList.add(map.get("mem").toString());stringList.add(map.get("screensize").toString());stringList.add(map.get("resolution_high").toString());stringList.add(map.get("resolution_width").toString());stringList.add(map.get("imei1").toString());stringList.add(map.get("imei2").toString());stringList.add(map.get("sn").toString());stringList.add(map.get("root").toString());stringList.add(map.get("color").toString());stringList.add(map.get("frontcam").toString());stringList.add(map.get("backcam").toString());stringList.add(map.get("usbcable").toString());stringList.add(map.get("charger").toString());stringList.add(map.get("headset").toString());stringList.add(map.get("battery").toString());stringList.add(map.get("phoneshell").toString());stringList.add(map.get("adddate").toString());stringList.add(map.get("managername").toString());stringList.add(map.get("name").toString());stringList.add(map.get("devicestatus").toString());stringList.add(map.get("devicenotes").toString());return stringList;}}