JAVA实现下载文件功能的两种方法

第一种方法：

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(); } }

第二种方法：

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(); }

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