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();    }