Response方式导出Excel

protected void downloadPaginExcel(HttpServletRequest request, HttpServletResponse response,Pagin<?> pagin,String fileName) throws Exception{
String columnObject = getParameter("columnObject");//字段对应关系
JSONArray myJsonArray =JSONArray.parseArray(columnObject);
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("工作表1");
sheet.setDefaultColumnWidth(18);
sheet.setDefaultRowHeightInPoints(20);
HSSFRow row = sheet.createRow((int) 0);
for(int i=0;i<myJsonArray.size();i++){
JSONObject newColumn = (JSONObject) myJsonArray.get(i);
String colName = (String) newColumn.get("title");
HSSFCell cell = row.createCell(i);
cell.setCellValue(colName);
}

for(int i=0;i< pagin.getResultList().size();i++){
Map<String,Object> newMap=ConvertObjToMap(pagin.getResultList().get(i));
row = sheet.createRow((int) i + 1);
for(int j=0;j<myJsonArray.size();j++){
JSONObject newColumn = (JSONObject) myJsonArray.get(j);
String col = (String) newColumn.get("dataIndex");
String valueNew =String.valueOf(newMap.get(col)) ;
row.createCell(j).setCellValue(valueNew);
}
}
String newFileName=fileName+".xls";
response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-disposition", "attachment;filename=" + java.net.URLEncoder.encode(newFileName, "UTF-8"));
OutputStream ouputStream = response.getOutputStream();
wb.write(ouputStream);
ouputStream.flush();
ouputStream.close();
}