servlet to implement file Download utility class sharing

 servlet file Download class, in order to prevent the client browser directly open the target file, in the response to join the mandatory download MIME type, we refer to use the bar

  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 (DOWNLOADFI Le.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; &nbs P &NBSP}    //read file stream    fis = new Java.io.FileInputStream (file);    //settings Download the saved file name &nbsP  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 ");   &NBSP} else if ("CH". Equals (browser)) {    contentdisposition = "attachment; Filename= "+ mimeutility.encodetext (showname," UTF8 "," B ");   &NBSP} else if ("SF". Equals (browser)) {    contentdisposition = "attachment; Filename= "+ New String (Showname.getbytes (" UTF-8 ")," iso8859-1 ");   &NBSP} else {    contentdisposition = "attachment; Filename*=utf-8 ' "+ Urlencoder.encode (showname," UTF-8 "). Replace (" + ","%20 ");   &nbsp    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) + "Ms. ");   &NBSP}  } catch (IOException IoE) {   ioe.printstacktrace ();  } finally {   try {     if (fis!=null) {     fis.close ();    }   &nbsp} catch (IOException e) {&nbs P &NBSP} finally {    try {     if (sos!=null) {      sos.close ();     & nbsp;}    } catch (IOException e) {   }   &nbsp}  } &nbsp}    public void DoPost (Ht Tpservletrequest 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 ("<html>");   OUT.PRINTLN ("<head>");   OUT.PRINTLN ("  <title> file Download </title>");   OUT.PRINTLN ("  <meta http-equiv=" Content-type "content=" text/html; Charset=utf-8 "/>");   OUT.PRINTLN ("</head>");   OUT.PRINTLN ("<body>");   Out.print ("This is");   Out.print (This.getclass (). GetName ());   OUT.PRINTLN (", using the" POST method);   OUT.PRINTLN ("</body>");   OUT.PRINTLN ("</html>");   Out.flush ();   Out.close (); &NBSP}    private string getbrowser (HttpServletRequest request) {  String useragent = Request.getheader ( "User-agent"). toLowerCase ();   if (useragent!= null) {   IF (Useragent.indexof ("MSIE") >= 0) {    return "IE";   &N BSP;} else if (Useragent.indexof ("Mozilla") >= 0 {    return "FF";    } else if ("Useragent.indexof" ("app Lewebkit ") >= 0 {    return" CH ";   &nbsp} else if (Useragent.indexof (" Safari ") >= 0) {  &NB Sp return "SF";   &NBSP} else if (Useragent.indexof ("opera") >= 0) {    return "OP";    }  }   RE Turn null; &NBSP}}