How to access servlet and download attachment?

Question

I have the following code snippet that tries to make an HTTP call to my servlet:

    try {
        // Construct data
        String data = URLEncoder.encode("rpt_type", "UTF-8") + "=" + URLEncoder.encode(reportType, "UTF-8");
        data += "&" + URLEncoder.encode("rpt_project", "UTF-8") + "=" + URLEncoder.encode(reportProject, "UTF-8");
        data += "&" + URLEncoder.encode("rpt_mrv_creator", "UTF-8") + "=" + URLEncoder.encode(reportMrvCreator, "UTF-8");
        data += "&" + URLEncoder.encode("rpt_gi_recipient", "UTF-8") + "=" + URLEncoder.encode(reportGiRecipient, "UTF-8");
        data += "&" + URLEncoder.encode("rpt_plant", "UTF-8") + "=" + URLEncoder.encode(reportPlant, "UTF-8");
        data += "&" + URLEncoder.encode("rpt_sloc", "UTF-8") + "=" + URLEncoder.encode(reportStorageLoc, "UTF-8");
        data += "&" + URLEncoder.encode("rpt_gi_no", "UTF-8") + "=" + URLEncoder.encode(reportGiNo, "UTF-8");
        data += "&" + URLEncoder.encode("date_sap_gi_fr", "UTF-8") + "=" + URLEncoder.encode(reportDateGiFrom, "UTF-8");
        data += "&" + URLEncoder.encode("date_sap_gi_to", "UTF-8") + "=" + URLEncoder.encode(reportDateGiTo, "UTF-8");
        data += "&" + URLEncoder.encode("rpt_partno", "UTF-8") + "=" + URLEncoder.encode(reportPartNo, "UTF-8");
        data += "&" + URLEncoder.encode("rpt_so_no", "UTF-8") + "=" + URLEncoder.encode(reportSvcOrderNo, "UTF-8");
        data += "&" + URLEncoder.encode("date_scan_fr", "UTF-8") + "=" + URLEncoder.encode(reportDateScanFrom, "UTF-8");
        data += "&" + URLEncoder.encode("date_scan_to", "UTF-8") + "=" + URLEncoder.encode(reportDateScanTo, "UTF-8");
        System.out.println("[data]\n" + data);

        // Send data
        String urlString = "http://localhost:8080/aerobook/GIStatusReportDownload?" + data;
        System.out.println("[url] " + urlString);
        URL url = new URL(urlString);
        URLConnection conn = url.openConnection();
        //conn.setDoOutput(true);
        //OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
        //wr.write(data);
        //wr.flush();

        // Get the response
        BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = rd.readLine()) != null) {
            System.out.println(line);
        }
        //wr.close();
        rd.close();
    } catch (Exception e) {
    }

My debug output:

[data]
rpt_type=d&rpt_project=aaa&rpt_mrv_creator=bbb&rpt_gi_recipient=ccc&rpt_plant=ddd&rpt_sloc=eee&rpt_gi_no=fff&date_sap_gi_fr=02%2F05%2F2012&date_sap_gi_to=03%2F05%2F2012&rpt_partno=ggg&rpt_so_no=hhh&date_scan_fr=26%2F05%2F2012&date_scan_to=31%2F05%2F2012
[url] http://localhost:8080/aerobook/GIStatusReportDownload?rpt_type=d&rpt_project=aaa&rpt_mrv_creator=bbb&rpt_gi_recipient=ccc&rpt_plant=ddd&rpt_sloc=eee&rpt_gi_no=fff&date_sap_gi_fr=02%2F05%2F2012&date_sap_gi_to=03%2F05%2F2012&rpt_partno=ggg&rpt_so_no=hhh&date_scan_fr=26%2F05%2F2012&date_scan_to=31%2F05%2F2012

On my servlet (in a separate file from the code above), I generate an Excel file for download:

    res.setContentType(sContentType);
    res.setHeader("Content-Disposition", "attachment;filename=\"" + sExcelFileName + "\"");
    OutputStream oOutStrm = res.getOutputStream();
    wbBook.write(oOutStrm);
    oOutStrm.close();

My issue here is that from the URL generated by my code (as shown in the debug output above), I can access my servlet and I manage to get the Save-As dialog.

I'd like to get the contents of the file generated for use within my code. Is there any way I can get the attachment from my code, in byte stream or any other format?

---

Edit #3: Cleaned up the top

Answer 1

I want to get the contents of the excel file on my code, but so far it's not working.

I find no errors in the code.
I believe you want to convert content from input stream to an HSSFWorkbook object.
Following code snippet will help you on it.

java.net.URLConnection conn = url.openConnection();  
java.io.InputStream is = conn.getInputStream();  
org.apache.poi.hssf.usermodel.HSSFWorkbook workBook = new org.apache.poi.hssf.usermodel.HSSFWorkbook( is );  
System.out.println( "Number of Sheets: " + workBook.getNumberOfSheets() );  
org.apache.poi.hssf.usermodel.HSSFSheet sheet = workBook.getSheetAt( 0 );  
System.out.println( "Sheet Name: " + sheet.getSheetName() );  

// rest of your code to handle the captured workBook
// cheers

Answer 2

When you enter the URI into the browser, you are doing a GET request. Your client Java code however produces a POST request, and sends the parameters in the body, not the URI.

You may want to look at an HTTP trace and compare.

Answer 3

Check wbBook.write(oOutStrm); whether anything has been written into outputStream, also you need call oOutStrm.flash() before close it.

Answer 4

I doubt that the problem lies at OutputStream oOutStrm = res.getOutputStream();.

I bet res is HttpServletResponse and it returns a ServletOutputStream suitable for writing binary data in the response. The servlet container does not encode the binary data

Check API

So, You might not be getting anything except fileName.

In Servlet Try

FileOutputStream stream = new FileOutputStream("c:/excel/Book1.xls");
workBook.write(stream);