Java 使用ApachePOI下载Excel

我希望在用户调用此方法时下载excel文件。文件下载成功，但正在project的类路径中创建另一个excel文件。有人能帮我避免创建这个类路径文件吗。 提前谢谢

@Override
    public void downloadExcel(HttpServletRequest request,HttpServletResponse response) throws IOException { 

              File file = new File("Segmentdetail.xlsx"); 

              XSSFWorkbook workbook = new XSSFWorkbook(); 
              XSSFSheet spreadsheet = workbook.createSheet("SegmentLogs Info");
              spreadsheet.setDefaultColumnWidth(20);
             .....Here is the logic for generating sheet which is quite big so iam skipping it.

             }           
             FileOutputStream out = new FileOutputStream(file);
             workbook.write(out);
             downloadFile(file,response);
             out.close();
             workbook.close();

    }

    private void downloadFile(File file, HttpServletResponse response){

        try {         
            response.setContentType("application/vnd.ms-excel");
            response.addHeader("content-disposition", "attachment; filename=Segmentdetail.xlsx");
            response.setHeader("Pragma", "public");
            response.setHeader("Cache-Control", "no-store");
            response.addHeader("Cache-Control", "max-age=0");
            FileInputStream fin = null;
            try {
                fin = new FileInputStream(file);
            } catch (final FileNotFoundException e) {
                e.printStackTrace();
            }
            final int size = 1024;
            try {
                response.setContentLength(fin.available());
                final byte[] buffer = new byte[size];
                ServletOutputStream outputStream = null;

                outputStream = response.getOutputStream();
                int length = 0;
                while ((length = fin.read(buffer)) != -1) {
                    outputStream.write(buffer, 0, length);
                }
                fin.close();
                outputStream.flush();
                outputStream.close();
            } catch (final IOException e) {
                e.printStackTrace();
            }
        }catch (final Exception ex){
            ex.printStackTrace();
    }

}

---

因为您正在使用下面的命令创建文件

File file = new File("Segmentdetail.xlsx"); 

它将在类路径中生成文件

下载时最好给出文件路径和相同的文件路径

File file = new File("c://Segmentdetail.xlsx"); 

---

为要将excel写入的文件使用绝对路径：

File file = new File(      "C:\\Segmentdetail.xlsx"); // windows
File file = new File("/home/usr/Segmentdetail.xlsx"); // unix    

合理的加法是使用变量：

File file = new File(System.getenv("user.home"), "Segmentdetail.xlsx");

---

当然，您也可以定义一个自定义变量并使用它。

对不起，我尝试了上面的一个变量，但最后出现了file not found异常。顺便说一句，我正在使用Ubuntu。然后指定路径如下/home/usr/Filename，并在下载时给出相同的路径，路径为Filename=No，它不工作，出现相同的异常。是否仍要将excel工作表保留在会话中并从那里下载？我不希望在本地计算机中创建该文件。它应该处于会话中并从那里下载。