Controller中的方法

//檔案下載
@RequestMapping("/upload")
public String uploadFile(@RequestParam("url") String url, HttpServletRequest request, HttpServletResponse response) {
    if (url != null) {
        String realPath = request.getSession().getServletContext().getRealPath("/upload");
File file = new File(realPath, 
 
url);
        if (file.exists()) {
            response.setContentType("application/force-download");// 設定強制下載不開啟
String fileName = url.substring(6);
response.addHeader("Content-Disposition", "attachment;fileName=" + fileName);// 設定檔名
byte[] buffer = new byte[1024];
FileInputStream fis = null;
BufferedInputStream bis = null;
 
            try {
                fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
OutputStream os = response.getOutputStream();
                int i = bis.read(buffer);
                while (i != -1) {
                    os.write(buffer, 0, i);
i = bis.read(buffer);
}
            } catch 
 
(Exception e) {
                e.printStackTrace();
} finally {
                if (bis != null) {
                    try {
                        bis.close();
} catch (IOException e) {
                        e.printStackTrace();
}
                }
                if (fis != null) {
                    try {
                        fis.close();
} catch (IOException e) {
                        e.printStackTrace();
}
                }
            }
        }
    }
    return null;
}