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;  }     

// 下载本地文件    public void downloadLocal(HttpServletResponse response) throws FileNotFoundException {  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();  }  }

 // 下载网络文件    public void downloadNet(HttpServletResponse response) throws MalformedURLException {  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();  }