java 實現對指定目錄的文件進行下載

     @RequestMapping("/exportDocument")
     @ResponseBody
     public void exportDocument(HttpServletRequest request,HttpServletResponse response) throws IOException {    
        XWPFDocument xdoc = null;
        FileInputStream is = null;
        OutputStream out=null; 
        try {
            String wordName="數聚空港2.0使用手冊.docx";
            wordName = new String(wordName.getBytes(), "iso8859-1");
            // File file = new File("/root/usersGuide.docx"); 
            response.setContentType("APPLICATION/OCTET-STREAM");
            response.setHeader("Content-Disposition", "attachment; filename="+ wordName);
            is = new FileInputStream("/root/usersGuide.docx");
            out=response.getOutputStream();//獲得一個output對象
            xdoc = new XWPFDocument(is);
            } catch (IOException e) {
                e.printStackTrace();
            }finally{
                try {
                    xdoc.write(out);//Write out this document to an Outputstream.
                    is.close();
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            /*上述是word文檔的下載*/


            /*下面是對各種類型的文件下載*/
        
                 /*
　　
　　　　　　　　　　//2.獲取要下載的文件名
                String fileName = "test.png";
                //3.設置content-disposition響應頭控制瀏覽器以下載的形式打開文件
                response.setHeader("content-disposition", "attachment;filename="+fileName);
                //4.獲取要下載的文件輸入流
                InputStream in=null;
                OutputStream out=null;
                try {//獲取要下載的文件的絕對路徑
                    in=new FileInputStream("/root/運營線路圖0.3.5版.png");
                    int len = 0;
                     //5.創建數據緩沖區
                     byte[] buffer = new byte[1024];
                     //6.通過response對象獲取OutputStream流
                     out = response.getOutputStream();
                     //7.將FileInputStream流寫入到buffer緩沖區
                     while ((len = in.read(buffer)) > 0) {//in.read(byte[] b)最多讀入b.length個字節 在碰到流的結尾時 返回-1
                     //8.使用OutputStream將緩沖區的數據輸出到客戶端瀏覽器
                         out.write(buffer,0,len);
                     }
                 }catch (FileNotFoundException e) {
                    e.printStackTrace();
                 }finally{
                     in.close();
                     out.close();
                 }*/            
    }