Java下载文件的几种方式
以流的方式下载
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(".") + ).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; }
下载本地文件
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[]; int len; try { while ((len = inStream.read(b)) > ) response.getOutputStream().write(b, , len); inStream.close(); } catch (IOException e) { e.printStackTrace(); } }
下载网络文件
public void downloadNet(HttpServletResponse response) throws MalformedURLException { // 下载网络文件 int bytesum = ; int byteread = ; 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[]; int length; while ((byteread = inStream.read(buffer)) != -1) { bytesum += byteread; System.out.println(bytesum); fs.write(buffer, , byteread); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } }
支持在线打开的方式
public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception { File f = new File(filePath); if (!f.exists()) { response.sendError(, "File not found!"); return; } BufferedInputStream br = new BufferedInputStream(new FileInputStream(f)); byte[] buf = new byte[]; int len = ; 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)) > ) out.write(buf, , len); br.close(); out.close(); }
