servlet implementation file Download utility class sharing

servlet implementation file Download utility class sharing _jsp programming

Last Update:2017-01-18 Source: Internet

Author: User

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Copy Code code as follows:

Package com;

Import java.io.IOException;
Import Java.io.PrintWriter;
Import Java.net.URLEncoder;
Import Java.util.Date;

Import javax.servlet.ServletException;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;

Import Org.apache.commons.logging.Log;
Import Org.apache.commons.logging.LogFactory;

Import com.sun.xml.internal.messaging.saaj.packaging.mime.internet.MimeUtility;

/**
* File Download class. To prevent the client browser from opening the destination file directly, such as IE in windows in which the MS Office suite is installed, you may be able to open the doc or xls file you want to download directly in the IE browser, and add the MIME type of the forced download in the response header.
*/
public class DownloadFile extends HttpServlet {
private static Final log = Logfactory.getlog (Downloadfile.class);

public void doget (HttpServletRequest request, httpservletresponse response) throws Servletexception {
Long Timestart = 0;
if (log.isdebugenabled ()) {
Timestart=system.currenttimemillis ();
}
Response.setcontenttype ("Application/x-download charset=utf-8");
Java.io.FileInputStream FIS = null;
String filepath = Request.getrealpath ("");
Javax.servlet.ServletOutputStream SOS = null;
SYSTEM.OUT.PRINTLN ("DownloadFile filename:" + filename);
try {
if (Request.getparameter ("filename") ==null
|| Request.getparameter ("ShowName") ==null) {
Return
}
String filename = request.getparameter ("filename");
String showname = Request.getparameter ("ShowName");
Request.setcharacterencoding ("UTF-8");
Response.setcharacterencoding ("UTF-8");
Java.io.File File = new Java.io.File (filepath + filename);
if (!file.exists ()) {
Log.error (File.getabsolutepath () + "file does not exist!");
Return
}
Reading file streams
FIS = new Java.io.FileInputStream (file);
Set the file name of the download save
SOS = Response.getoutputstream ();
ShowName + = filename.substring (Filename.lastindexof ("."));
String contentdisposition = "", browser = getbrowser (request);
if ("IE". Equals (browser)) {
Contentdisposition = "attachment; Filename= "+ urlencoder.encode (showname," UTF-8 "). Replace (" + ","%20 ");
else if ("CH". Equals (browser)) {
Contentdisposition = "attachment; Filename= "+ mimeutility.encodetext (showname," UTF8 "," B ");
else if ("SF". Equals (browser)) {
Contentdisposition = "attachment; Filename= "+ New String (Showname.getbytes (" UTF-8 ")," iso8859-1 ");
} else {
Contentdisposition = "attachment; Filename*=utf-8 ' "+ Urlencoder.encode (showname," UTF-8 "). Replace (" + ","%20 ");
}
Response.setheader ("Content-disposition", contentdisposition);
int byteCount = 0;
if (FIS!= null) {
byte[] buff = new byte[1024];
int bytesread;
while ( -1!= (bytesread = fis.read (buff, 0, buff.length))) {
Sos.write (Buff, 0, bytesread);
Sos.flush ();
ByteCount + = Bytesread;
}
}
Sos.flush ();
if (log.isdebugenabled ()) {
Log.debug ("File download complete, File size: + ByteCount +", in total: "+ (New Date (). GetTime ()-Timestart) +" milliseconds. ");
}
catch (IOException IoE) {
Ioe.printstacktrace ();
finally {
try {
if (fis!=null) {
Fis.close ();
}
catch (IOException e) {
finally {
try {
if (sos!=null) {
Sos.close ();
}
catch (IOException e) {
}
}
}
}

public void DoPost (HttpServletRequest request, httpservletresponse response) throws Servletexception, IOException {
Response.setcontenttype ("text/html");
PrintWriter out = Response.getwriter ();
Out.println ("<! DOCTYPE HTML public \ "-//W3C//DTD XHTML 1.0 transitional//en\" \ "http://www.w3.org/TR/xhtml1/DTD/ Xhtml1-transitional.dtd\ ">");
Out.println ("Out.println ("Out.println ("<title> file Download </title>");
Out.println ("<meta http-equiv=\" content-type\ "content=\" text/html; charset=utf-8\ "/>");
Out.println ("Out.println ("<body>");
Out.print ("This is");
Out.print (This.getclass (). GetName ());
Out.println (", using the" POST method);
Out.println ("</body>");
Out.println ("Out.flush ();
Out.close ();
}

Private String Getbrowser (HttpServletRequest request) {
String useragent = Request.getheader ("User-agent"). toLowerCase ();
if (useragent!= null) {
if (Useragent.indexof ("MSIE") >= 0) {
return "IE";
else if (Useragent.indexof ("Mozilla") >= 0) {
return "FF";
else if (Useragent.indexof ("AppleWebKit") >= 0) {
return "CH";
else if (Useragent.indexof ("Safari") >= 0) {
return "SF";
else if (Useragent.indexof ("opera") >= 0) {
return "OP";
}
}
return null;
}
}

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

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