Spring Boot项目实现从系统目录中下载指定文件（D盘下,测试文件1.txt）

@RequestMapping(value = "/downloadFileFromSysDir")
public void downloadFileFromSysDir(HttpServletResponse response) {
String fileName = "1.txt";
response.setHeader("content-type","application/octet-stream");
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition","attachment;filename=" + fileName);
byte[] buff = new byte[1024];
BufferedInputStream bis = null;
OutputStream os = null;
try {
os = response.getOutputStream();
bis = new BufferedInputStream(new FileInputStream(new File("D://"+ fileName)));
int i = bis.read(buff);
while (i != -1) {
os.write(buff, 0, buff.length);
os.flush();
i = bis.read(buff);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("成功下载");
}
}