Display or download Files using servlet

/**
 *
 */
package com.jijo.servlet;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author jijo
 * This servlet class is used to display or download the file
 *
 */
public class DownloadFile extends HttpServlet{
   
   
   
    /**
     *
     */
    private static final long serialVersionUID = 1L;
   
    public void doGet(HttpServletRequest request, HttpServletResponse response)    throws ServletException, IOException {
        doPost(request, response);
    }
   
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        ServletOutputStream outputStream = null;
        InputStream input = null;
       
        try {
            outputStream = response.getOutputStream();
            String filePath = request.getParameter("fileNames");  //filepath
            if(filePath != null && filePath.trim().length()>0){               
                String download = request.getParameter("download");//download or display
                File prefile = new File(filePath);
                byte buff[] = new byte[8192];
                input = new FileInputStream(prefile);
                String contenttype = filePath.substring(filePath.lastIndexOf(".")+1, filePath.length());
                contenttype = contenttype.toLowerCase();
               
                if(download != null && download.trim().length()>0){
                      response.setContentType("application/octet-stream");
                }
                else{
                    if (contenttype != null) {
                        String responseType = getResponseContentType(contenttype);
                        response.setContentType(responseType);                        
                    } else {
                        response.setContentType("application/octet-stream");
                    }
                }          
                response.setHeader("Content-Length", String.valueOf(prefile.length()));          
                if(download != null && download.trim().length()>0){
                    response.setHeader("Content-Disposition","attachment; filename=\""+ prefile.getName()+"\"");
                }
                else{
                    response.setHeader("Content-disposition", (new StringBuilder("inline; filename=")).append(prefile.getName()).toString());
                }
                response.addHeader("Cache-Control", "no-transform, max-age=0");  
                int i = 0;
                while ((i = input.read(buff)) > 0) {
                    outputStream.write(buff, 0, i);
                    outputStream.flush();
                }
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            if (input != null)
                input.close();
            if (outputStream != null)
                outputStream.close();
        }
    }
    private String getResponseContentType(String contenttype){
        String responseType = "";
        if(contenttype.indexOf("doc")>-1){
            responseType = "application/vnd.ms-word";
        }
        if(contenttype.indexOf("rtf")>-1){
            responseType = "application/rtf";
        }
        else if(contenttype.indexOf("xls")>-1){
            responseType = "application/vnd.ms-excel";
        }   
        else if(contenttype.indexOf("ppt")>-1){
            responseType = "application/ppt";
        }
        else if(contenttype.indexOf("xml")>-1){
            responseType = "text/xml";
        }
        else if(contenttype.indexOf("html")>-1){
            responseType = "text/html"; 
        }
        else if(contenttype.indexOf("htm")>-1){
            responseType = "text/htm"; 
        } 
        else if(contenttype.indexOf("txt")>-1 || contenttype.indexOf("log")>-1){
            responseType = "text/plain";
        }   
        else if(contenttype.indexOf("pdf")>-1){
            responseType = "application/pdf";
        }
        else if(contenttype.indexOf("gif")>-1){
            responseType = "image/gif";
        }
        else if(contenttype.indexOf("png")>-1){
            responseType = "image/png";
        }
        else if(contenttype.indexOf("jpg")>-1){
            responseType = "image/jpg";
        }
        else if(contenttype.indexOf("jpeg")>-1){
            responseType = "image/JPEG";
        }
        else if(contenttype.indexOf("jpe")>-1){
            responseType = "image/JPEG";
        }
        else if(contenttype.indexOf("bmp")>-1){
            responseType = "image/bmp";
        }
        else if(contenttype.indexOf("jpeg")>-1){
            responseType = "image/JPEG";
        }
        else if(contenttype.indexOf("tiff")>-1){
            responseType = "image/tiff";
        }
        else if(contenttype.indexOf("tif")>-1){
            responseType = "image/tiff";
        }       
        else if(contenttype.indexOf("html")>-1){
            responseType = "text/html";
        }
        else{
            responseType = "application/octet-stream";
        }
        return responseType;
    }
   
}




in web.xml


<servlet>
        <servlet-name>ViewFile</servlet-name>
        <servlet-class>com.jijo.servlet.DownloadFile</servlet-class>
    </servlet>   
    <servlet-mapping>
        <servlet-name>ViewFile</servlet-name>
        <url-pattern>*.viewfile</url-pattern>
    </servlet-mapping>


    <mime-mapping>
        <extension>pptx</extension>
        <mime-type>
            application/vnd.openxmlformats-officedocument.presentationml.presentation
        </mime-type>
    </mime-mapping>
   
    <mime-mapping> 
        <extension>docx</extension> 
         <mime-type>application/vnd.openxmlformats-officedocument.wordprocessingml.document</mime-type> 
     </mime-mapping> 
     <mime-mapping> 
        <extension>xlsx</extension> 
        <mime-type>application/vnd.openxmlformats-officedocument.spreadsheetml.sheet</mime-type> 
     </mime-mapping> 




in jsp

<form name='form1' method="post" action="file.viewfile" target="fileframe"/>
<input type='hidden' name='fileNames' id='fileNames' value='C:/jijo/resume.txt'/>
<input type='hidden' name='download' id='download' value='true'/>//set as blank when u want to display
<input type='Submit' name='Submit' id='Submit' value='Display'/>
</form>
<frame name="fileframe" id="fileframe"></frame>