java文件下载的几种方式

//Java文件下载的几种方式  

 

    public HttpServletResponse download(String path, HttpServletResponse response) {  

        try {  

            // path是指欲下载的文件的路径。  

            File file = new File(path);  

            // 取得文件名。  

            String filename = file.getName();  

            // 取得文件的后缀名。  

            String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();  

 

            // 以流的形式下载文件。  

            InputStream fis = new BufferedInputStream(new FileInputStream(path));  

            byte[] buffer = new byte[fis.available()];  

            fis.read(buffer);  

            fis.close();  

            // 清空response  

            response.reset();  

            // 设置response的Header  

            response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));  

            response.addHeader("Content-Length", "" + file.length());  

            OutputStream toClient = new BufferedOutputStream(response.getOutputStream());  

            response.setContentType("application/octet-stream");  

            toClient.write(buffer);  

            toClient.flush();  

            toClient.close();  

        } catch (IOException ex) {  

            ex.printStackTrace();  

        }  

        return response;  

    }  

 

    public void downloadLocal(HttpServletResponse response) throws FileNotFoundException {  

        // 下载本地文件  

        String fileName = "Operator.doc".toString(); // 文件的默认保存名  

        // 读到流中  

        InputStream inStream = new FileInputStream("c:/Operator.doc");// 文件的存放路径  

        // 设置输出的格式  

        response.reset();  

        response.setContentType("bin");  

        response.addHeader("Content-Disposition", "attachment; filename=/"" + fileName + "/"");  

        // 循环取出流中的数据  

        byte[] b = new byte[100];  

        int len;  

        try {  

            while ((len = inStream.read(b)) > 0)  

                response.getOutputStream().write(b, 0, len);  

            inStream.close();  

        } catch (IOException e) {  

            e.printStackTrace();  

        }  

    }  

 

    public void downloadNet(HttpServletResponse response) throws MalformedURLException {  

        // 下载网络文件  

        int bytesum = 0;  

        int byteread = 0;  

 

        URL url = new URL("windine.blogdriver.com/logo.gif");  

 

        try {  

            URLConnection conn = url.openConnection();  

            InputStream inStream = conn.getInputStream();  

            FileOutputStream fs = new FileOutputStream("c:/abc.gif");  

 

            byte[] buffer = new byte[1204];  

            int length;  

            while ((byteread = inStream.read(buffer)) != -1) {  

                bytesum += byteread;  

                System.out.println(bytesum);  

                fs.write(buffer, 0, byteread);  

            }  

        } catch (FileNotFoundException e) {  

            e.printStackTrace();  

        } catch (IOException e) {  

            e.printStackTrace();  

        }  

    }  

 

//支持在线打开文件的一种方式  

    public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception {  

        File f = new File(filePath);  

        if (!f.exists()) {  

            response.sendError(404, "File not found!");  

            return;  

        }  

        BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));  

        byte[] buf = new byte[1024];  

        int len = 0;  

 

        response.reset(); // 非常重要  

        if (isOnLine) { // 在线打开方式  

            URL u = new URL("file:///" + filePath);  

            response.setContentType(u.openConnection().getContentType());  

            response.setHeader("Content-Disposition", "inline; filename=" + f.getName());  

            // 文件名应该编码成UTF-8  

        } else { // 纯下载方式  

            response.setContentType("application/x-msdownload");  

            response.setHeader("Content-Disposition", "attachment; filename=" + f.getName());  

        }  

        OutputStream out = response.getOutputStream();  

        while ((len = br.read(buf)) > 0)  

            out.write(buf, 0, len);  

        br.close();  

        out.close();  

    }