java实现文件下载的两种方式-文件下载

1. public HttpServletResponse download(String path, HttpServletResponse response) {
2. try {
3. // path是指欲下载的文件的路径。
4. File file = new File(path);
5. // 取得文件名。
6. String filename = file.getName();
7. // 取得文件的后缀名。
8. String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();
10. // 以流的形式下载文件。
11. InputStream fis = new BufferedInputStream(new FileInputStream(path));
12. byte[] buffer = new byte[fis.available()];
13. fis.read(buffer);
14. fis.close();
15. // 清空response
16. response.reset();
17. // 设置response的Header
18. response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));
19. response.addHeader("Content-Length", "" + file.length());
20. OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
21. response.setContentType("application/octet-stream");
22. toClient.write(buffer);
23. toClient.flush();
24. toClient.close();
25. } catch (IOException ex) {
26. ex.printStackTrace();
27. }
28. return response;
29. }
31. public void downloadLocal(HttpServletResponse response) throws FileNotFoundException {
32. // 下载本地文件
33. String fileName = "Operator.doc".toString(); // 文件的默认保存名
34. // 读到流中
35. InputStream inStream = new FileInputStream("c:/Operator.doc");// 文件的存放路径
36. // 设置输出的格式
37. response.reset();
38. response.setContentType("bin");
39. response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
40. // 循环取出流中的数据
41. byte[] b = new byte[100];
42. int len;
43. try {
44. while ((len = inStream.read(b)) > 0)
45. response.getOutputStream().write(b, 0, len);
46. inStream.close();
47. } catch (IOException e) {
48. e.printStackTrace();
49. }
50. }
52. public void downloadNet(HttpServletResponse response) throws MalformedURLException {
53. // 下载网络文件
54. int bytesum = 0;
55. int byteread = 0;
57. URL url = new URL("windine.blogdriver.com/logo.webp");
59. try {
60. URLConnection conn = url.openConnection();
61. InputStream inStream = conn.getInputStream();
62. FileOutputStream fs = new FileOutputStream("c:/abc.webp");
64. byte[] buffer = new byte[1204];
65. int length;
66. while ((byteread = inStream.read(buffer)) != -1) {
67. bytesum += byteread;
68. System.out.println(bytesum);
69. fs.write(buffer, 0, byteread);
70. }
71. } catch (FileNotFoundException e) {
72. e.printStackTrace();
73. } catch (IOException e) {
74. e.printStackTrace();
75. }
76. }

//支持在线打开文件的一种方式

1. 
   
2. public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception {
3. File f = new File(filePath);
4. if (!f.exists()) {
5. response.sendError(404, "File not found!");
6. return;
7. }
8. BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));
9. byte[] buf = new byte[1024];
10. int len = 0;
12. response.reset(); // 非常重要
13. if (isOnLine) { // 在线打开方式
14. URL u = new URL("file:///" + filePath);
15. response.setContentType(u.openConnection().getContentType());
16. response.setHeader("Content-Disposition", "inline; filename=" + f.getName());
17. // 文件名应该编码成UTF-8
18. } else { // 纯下载方式
19. response.setContentType("application/x-msdownload");
20. response.setHeader("Content-Disposition", "attachment; filename=" + f.getName());
21. }
22. OutputStream out = response.getOutputStream();
23. while ((len = br.read(buf)) > 0)
24. out.write(buf, 0, len);
25. br.close();
26. out.close();