Servlet File Download

[Introduction]

A ServletFile Download.

 

[Folder structure]

 

[Java code]

1 package COM. zjm. www. servlet; 2 3 Import Java. io. bufferedinputstream; 4 Import Java. io. bufferedoutputstream; 5 import Java. io. file; 6 Import Java. io. fileinputstream; 7 Import Java. io. ioexception; 8 Import Java. io. inputstream; 9 Import Java. io. outputstream; 10 11 import javax. servlet. servletexception; 12 Import javax. servlet. HTTP. httpservlet; 13 Import javax. servlet. HTTP. httpservletrequest; 14 Import J Avax. servlet. HTTP. httpservletresponse; 15 16/** 17 * @ description Servlet File Download 18 * @ author M19 * @ blog http://www.cnblogs.com/xiaoMzjm/20 * @ time 2014/07/3021 */22 public class downloadservlet extends httpservlet {23 24 25 private Static final long serialversionuid = 1l; 26 27 public void doget (httpservletrequest request, httpservletresponse response) 28 throws servletexception, ioexception {29 dopost (request, respon Se); 30} 31 32 public void dopost (httpservletrequest request, httpservletresponse response) 33 throws servletexception, ioexception {34 35 // transcoding, filter is recommended. 36 request. setcharacterencoding ("utf8"); 37 response. setcharacterencoding ("utf8"); 38 39 // get the file name 40 string filename = request. getparameter ("FILENAME"); 41 42 // folder of the file, relative path of the Server File. For Path Problems, refer to another blog: http://www.cnblogs.com/xiaoMzjm/p/3878758.html43 string Path = request. getservletcontext (). getrealpath ("/") + "\ downloadfile \"; 44 // download Path = folder where the file is stored + file name 46 string downloadpath = path + filename; 47 48 // create an input stream connection file and read the file to the stream. 49 file = new file (downloadpath); 50 inputstream FD = new bufferedinputstream (New fileinputstream (File )); 51 52 // determine how many bytes a file can read 53 byte [] buffer = new Te [FCM. available ()]; 54. read (buffer); 55 FS. close (); 56 57 // clear response58 response. reset (); 59 60/** 61 * set the response header, which must be set. 62 * [Introduction to several header files]: 63*1. Content-disposition is an extension of the mime protocol. This protocol allows the browser to pop up a download box. You can also change the file name during download. 64*2. Content-Length describes the transmission length of an HTTP message object. 65 * in HTTP, the length of a message entity differs from that of a message entity. For example, in gzip compression, the length of a message entity is the length before compression, the transmission length of the message entity is the length after gzip compression. 66 */67 response. addheader ("content-disposition", "attachment; filename =" + new string (filename. getbytes ("UTF-8"), "ISO-8859-1"); 68 response. addheader ("Content-Length", "" + file. length (); 69 outputstream out = new bufferedoutputstream (response. getoutputstream (); 70 71/** 72 * configure the MIME type to notify the browser of the format of the downloaded file. 73 * more MIME type and suffix ing can be found in Baidu Library search: "MIME type Daquan" or in the Stamp connection: 74 * http://wenku.baidu.com/link? Url = SIJffXFE68HnvhI39h0c0PtjSzz7v8SoYzo274HcEx8jYRm-V07_WkotLQdVnT_JGyNhIUY_bjQRgnfz_b53rg5EnHD_ist84Pq-uWMYjyG75 */76 response. setcontenttype ("application/octet-stream"); 77 78 // output 79 out. write (buffer); 80 out. flush (); 81 out. close (); 82} 83}