public void download(HttpServletRequest request, HttpServletResponse response){
        //獲取服務器文件
        String file_url = "http//:www.baidu.com/201811239413.doc";

        InputStream ins = null;
        try {
            ins = new URL(file_url).openStream();
            /* 設置文件ContentType類型，這樣設置，會自動判斷下載文件類型 
 
*/
            response.setContentType("multipart/form-data");
            /* 設置文件頭：最後一個參數是設置下載文件名 */
            response.setHeader("Content-Disposition", "attachment;filename*=UTF-8‘‘" + URLEncoder.encode("江蘇南京.doc","UTF-8"));//適應中文名稱
            OutputStream os = response.getOutputStream();
            
 
byte[] b = new byte[1024];
            int len;
            while((len = ins.read(b)) > 0){
                os.write(b,0,len);
            }
            os.flush();
            os.close();
            ins.close();
        } catch (FileNotFoundException e) {
            System.out.println("沒有該文件");
        } 
 
catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

java 網絡文件下載（並命中文名）