spring和mybatis框架中实现文件下载功能

//文件下载
@RequestMapping(value = "/downFile")
public void downFile(FileBean fileBean, HttpServletRequest request, HttpServletResponse response) {
BufferedInputStream in = null;
BufferedOutputStream out = null;
try {
//根据id单条查询出文件实体对象
fileBean = fileService.queryFileById(id);

response.setContentType("text/html;charset=UTF-8");
String rootpath = request.getSession().getServletContext().getRealPath("/");

//fileBean.getfilepath()表示获取文件实体对象中的路径
File f = new File(rootpath + File.separator + fileBean.getfilepath());

response.reset();
response.setContentType("application/x-excel");
response.setCharacterEncoding("UTF-8");

//fileBean.getname()表示获取文件实体对象中的名称
response.setHeader("Content-Disposition", "attachment; filename=" + new String(fileBean.getname().getBytes("gbk"),"iso-8859-1"));

response.setHeader("Content-Length",String.valueOf(f.length()));
in = new BufferedInputStream(new FileInputStream(f));
out = new BufferedOutputStream(response.getOutputStream());
byte[] data = new byte[1024];
int len = 0;
while (-1 != (len=in.read(data, 0, data.length))) {
out.write(data, 0, len);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}