java servlet programming

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July 29, 2008 at 8:14 PM

Hi friend,

i am sending multiple download file example.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
</HEAD>

<BODY>
<form name="frm" action="dmfile" method="post">
<table>
<tr><td>Download Multiple File</td></tr>
<tr><td><input type="checkbox" name="chk0" value="/check.html">File One</td></tr>
<tr><td><input type="checkbox" name="chk1" value="/okalert.html">File Two</td></tr>
<tr><td><input type="checkbox" name="chk2" value="/pdetails.jsp">File Three</td></tr>
<tr><td><input type="submit" name="download" value="Download"></td></tr>
</table>
</form>
</BODY>
</HTML>

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July 29, 2008 at 8:15 PM

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DownloadMultiFile extends HttpServlet {
final boolean file = true;
public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException{
final byte[] CRLF = new byte[]{(byte)'\r', (byte)'\n'};
String boundaryTxt = "--AMZ90RFX875LKMFasdf09DDFF3";

String fname = "" ;
if(req.getParameter("chk0")!=null)
{
fname = req.getParameter("chk0").toString();
if(req.getParameter("chk1")!=null)
{
fname = fname +","+req.getParameter("chk1").toString();

}

if(req.getParameter("chk2")!=null)
{
fname = fname +","+req.getParameter("chk2").toString();
}
}
if(req.getParameter("chk1")!=null)
{
fname = req.getParameter("chk1").toString();
if(req.getParameter("chk2")!=null)
{
fname = fname +","+req.getParameter("chk2").toString();

}
if(req.getParameter("chk0")!=null)
{
fname = fname +","+req.getParameter("chk0").toString();
}
}
if(req.getParameter("chk2")!=null)
{
fname = req.getParameter("chk2").toString();
if(req.getParameter("chk1")!=null)
{
fname = fname +","+req.getParameter("chk1").toString();

}
if(req.getParameter("chk0")!=null)
{
fname = fname +","+req.getParameter("chk0").toString();
}
}

System.out.println("fname :::::::::::::" + fname);
String [] temp = null;
temp = fname.split(",");

System.out.println("temp " + temp.length);

String fileName = "Download_MultiFile";
res.setContentType("multipart/x-mixed-replace;boundary=" + boundaryTxt.substring(2));
// Read from file into servlet output stream
ServletOutputStream stream = res.getOutputStream();
byte[] boundary = boundaryTxt.getBytes();
stream.write(boundary, 0, boundary.length);
stream.write(CRLF, 1, 1);
byte[] contentType = "Content-type: text/plain\n".getBytes();

// Write out a couple of files
for(int i = 0; i < temp.length; i++) {
stream.write(contentType, 0, contentType.length);
byte[] contDisp = ("Content-Disposition: attachment; filename=" + fileName + i + "\r\n\r\n").getBytes();
stream.write(contDisp, 0, contDisp.length);
// Lets read this file???
System.out.println("fname "+ temp[i]);

BufferedInputStream buff = new BufferedInputStream(new FileInputStream(temp[i]));
if (file) System.out.println("Successfully sending file " + i + " to client as '" + fileName + i +"'");
int data = 0;
int byteCnt = 0;
while((data = buff.read()) != -1) {
stream.write(data);
byteCnt++;
}
buff.close();
stream.write(boundary, 0, boundary.length); // write bndry after data
stream.write(CRLF, 1, 1);
if (file) System.out.println("Successfully download file " + i +". " + byteCnt + " bytes");
}// end for(i) outputing files
byte[] endBndry = (boundary + "--").getBytes();
stream.write(endBndry, 0, endBndry.length); // write the ending boundary
stream.close();
}
}

July 29, 2008 at 8:15 PM

Read for more information.

http://www.roseindia.net/servlets/

Thanks.