com.ibm.bluemix.samples.DownloadServlet.java Source code

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Here is the source code for com.ibm.bluemix.samples.DownloadServlet.java

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package com.ibm.bluemix.samples;

import java.io.IOException;
import java.io.OutputStream;

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

import org.json.simple.JSONObject;

/**
 * This method receives the clean text file or the analysis XML file from the
 * database and returns it to the user for downloading.
 */
@SuppressWarnings("serial")
public class DownloadServlet extends HttpServlet {

    /**
     * object of the PostgreSQLClient class to access and alter the database
     */
    private PostgreSQLClient db = new PostgreSQLClient();

    /**
     * Receives the clean text file or the analysis XML file from the database and returns it to the user
     * 
     * @param request
     *           contains the type of the requested file (text or XML) and the ID of the file in the database
     * @param response
     *           the file to be downloaded
     *           
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        System.out.println("Download Servlet");

        try {
            // Retrive file information and data
            JSONObject fileInfo = db.getFileInfo(request.getParameter("entry_id"));
            String contentType = null;
            String fileName = null;
            byte[] fileData = null;

            if (request.getParameter("type").equals("1")) {
                // Request for the original file
                fileData = db.getOriginalFile(request.getParameter("entry_id"));
                contentType = "text/plain";
                fileName = (String) fileInfo.get("file_name");
            } else {
                // Request for the output file
                fileData = db.getOutputFile(request.getParameter("entry_id"));
                contentType = "application/xml";
                fileName = (String) fileInfo.get("output_name");
            }

            // Set response headers
            response.setHeader("Content-disposition", "attachment; filename=" + fileName);
            response.setContentType(contentType);
            response.setStatus(200);

            // Write data to output stream
            OutputStream responseOutput = response.getOutputStream();
            responseOutput.write(fileData, 0, fileData.length);
            responseOutput.flush();
            responseOutput.close();

        } catch (Exception e) {
            request.setAttribute("msg", e.getMessage());
            e.printStackTrace(System.err);
        }
    }
}