用servlets实现web方式的文件下载

// download.java
import java.io.*;
import java.text.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.net.*;
/**
* the simplest download servlet.
*
* @author huang jian-chang
*/
public class download extends httpservlet {
public void dopost(httpservletrequest request,
httpservletresponse response)
throws ioexception, servletexception
{
response.setcontenttype( "application/doc" ); // mime type for pdf doc
response.setheader("content-disposition",
"attachment; filename=" +
"table.doc" );
string fileurl = "http://hjc/table.doc";
url url=new url(fileurl);
bufferedinputstream bis = new bufferedinputstream(url.openstream());
bufferedoutputstream bos = new bufferedoutputstream( response.getoutputstream());
byte[] buff = new byte[2048];
int bytesread;
while (-1!=(bytesread=(bis.read(buff,0,buff.length)))){
bos.write(buff,0,bytesread);
}
if (bis!=null){
bis.close();
}
if (bos!=null){
bos.close();
}
}
}