[Myfaces Wiki] Update of "Sending Files (like PDF) to the Browser" by ozwolverine

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http://wiki.apache.org/myfaces/Sending_Files_%28like_PDF%29_to_the_Browser

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= Sending Files (like PDF) to the Browser How To =

== Introduction ==
When you need the user to be able to download a file that is stored somewhere in the server. 
So the idea is to send the file to the Response, then the user will be presented with a 
Open/save dialog for him/her to take the required action.

== How to do it ==
You have to bind an action in the JSP to a method in your backing bean 

The content of the method could be like this

'''//We must get first our context'''
 FacesContext context = FacesContext.getCurrentInstance();
      
'''//Then we have to get the Response where to put write our file'''
      HttpServletResponse response = 
         ( HttpServletResponse ) context.getExternalContext().getResponse();
      
'''//Now we create some variable we will use for writting the file to the response'''
      String filePath = null;
      int read = 0;
      byte[] bytes = new byte[1024];
      
'''//Be sure to retrieve the absolute path to the file with the required method'''
      filePath = pathToTheFile; 
      
'''//Now set the content type for our response, be sure to user the correct'''
'''//this content type is ok for, lets say some kind of text file (like a csv)'''
      response.setContentType("application/pdf");

'''//This is another important attribute for the header of the response'''
'''//Here fileName, is a String with the name that you will suggest as a name to save as'''
'''//I use the same name as it is stored in the file system of the server.'''

      response.setHeader("Content-Disposition", "attachment;filename=\"" +
         fileName + "\""); 

'''//Streams to use'''
      FileInputStream fis = null;
      OutputStream os = null;
      
'''//First we load the file in our InputStream      '''
         fis = new FileInputStream(new File(filePath ));
         os = response.getOutputStream();

'''//While there are still bytes in the file, read them and write them to our OutputStream'''
         while((read = fis.read(bytes)) != -1){
            os.write(bytes,0,read);
         }

'''//Clean resources'''

         os.flush();
         os.close();

'''//This option isn't quite necessary, It worked for me with or without it'''
         FacesContext.getCurrentInstance().responseComplete();
    
'''//End of the method  '''