Struts – download file from website example
Published: April 23, 2010 , Updated: April 16, 2010 , Author: mkyong
To let user download a file from your Struts web project, you have to inform “HttpServletResponse” to return an application file instead of the normal HTML page.
response.setContentType("application/octet-stream"); response.setHeader("Content-Disposition", "attachment;filename=downloadfilename.csv");
In server side, you can get the download file from 3 different ways
1. File system
Get it from file system
FileInputStream in = new FileInputStream(new File("C:\\filename.zip"));
2. Project web path
Assume your file is located at “http://yourname.com/StrutsExample/upload/filename.zip“, and the “StrutsExample” is your project name (serlvet context).
//jndi:/yourname.com/StrutsExample/upload/filename.zip URL url = getServlet().getServletContext().getResource("upload/filename.zip"); InputStream in = url.openStream();
3. Bytes array
If you retrieve the files or blob data from database, it’s usually return as bytes array.
byte[] bytes = new byte[4096]; InputStream in = new ByteArrayInputStream(bytes);
Download this Struts download file example – Struts-Download-File-Example.zip
1. Action class
An action class to return an application file instead of the normal HTML page, and get the “superfish.zip” file for user to download.
package com.mkyong.common.action; import java.io.ByteArrayInputStream; import java.io.File; import java.io.FileInputStream; import java.io.InputStream; import java.net.URL; import javax.servlet.ServletContext; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.struts.action.Action; import org.apache.struts.action.ActionForm; import org.apache.struts.action.ActionForward; import org.apache.struts.action.ActionMapping; public class DownloadFileAction extends Action{ @Override public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { //return an application file instead of html page response.setContentType("application/octet-stream"); response.setHeader("Content-Disposition","attachment;filename=superfish.zip"); try { //Get it from file system FileInputStream in = new FileInputStream(new File("C:\\superfish.zip")); //Get it from web path //jndi:/localhost/StrutsExample/upload/superfish.zip //URL url = getServlet().getServletContext() // .getResource("upload/superfish.zip"); //InputStream in = url.openStream(); //Get it from bytes array //byte[] bytes = new byte[4096]; //InputStream in = new ByteArrayInputStream(bytes); ServletOutputStream out = response.getOutputStream(); byte[] outputByte = new byte[4096]; //copy binary content to output stream while(in.read(outputByte, 0, 4096) != -1){ out.write(outputByte, 0, 4096); } in.close(); out.flush(); out.close(); }catch(Exception e){ e.printStackTrace(); } return null; } }
2. JSP Page
<%@taglib uri="http://struts.apache.org/tags-html" prefix="html"%> <html> <head> </head> <body> Download file from server - <html:link action="/DownloadIt">struts-tutorial.zip</html:link> </body> </html>
3. struts-config.xml
Struts configuration file.
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_3.dtd"> <struts-config> <action-mappings> <action path="/DownloadPage" type="org.apache.struts.actions.ForwardAction" parameter="/pages/display.jsp"/> <action path="/DownloadIt" type="com.mkyong.common.action.DownloadFileAction" > </action> </action-mappings> </struts-config>
4. Test it
http://localhost:8080/StrutsExample/DownloadPage.do
Hi ,
I have tried this code . I am picking up Excel file from path on disk .
It only works with Firefox, chrome , safari but has problem with IE 8 .
Please help with any suggestion .
My code snippet :
String disHeader = “attachment; filename=”;
ServletOutputStream opstream = response.getOutputStream();
response.setContentType( “application/x-excel” );
response.setHeader( “content-disposition”,disHeader+ fileName );
byte[] buf = new byte[4096];
while( (length=fileToDownload.read(buf,0,4096)) != -1 )
{
//byte[] defaultBytes = (new String(buf)).getBytes(“GBK”);
// String newEncodingStr = new String(defaultBytes, “UTF-8″);
opstream.write(buf,0,length);
}
fileToDownload.close();
opstream.flush();
opstream.close();
How to retrieve a file from database based on search content in struts
how can i refresh the jsp page again?
if i use
return mapping.findForward(“success”);
instead of
return null;,
it gives error that response already….
Sir Your Code was very Good….
it really Works Well.
Thanks a lot Sir.
Sir i wann to know that how i implement autocomplete off in html tag in struts please answer it.
how can i extend this code to run in struts 2?
I am glad to find so various helpful information here within the post, we need develop additional techniques in this regard, thanks for sharing
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