I am working in a old project.The project is in Spring MVC .In the project I have to generate a pdf file from a jsp page and store in a location and download that file. For that I am using wkhtmltopdf tool to convert the one specific jsp page into pdf format. Using wkhtmltopdf sometime works fine, it generate the pdf in specific location, but sometime it require more time. Also when I am trying to download the file from specific location , sometime it download a 0KB size file or sometime the downloaded file can't be open (with some size) but sometime download perfectly. If I check the file at define location, it exist and open normally. Here is my code in controller class.
@RequestMapping(value="/dwn.htm",method=RequestMethod.GET)
public void dwAppFm(HttpSession session,HttpServletRequest request,HttpServletResponse response,@RequestParam String id) throws IOException,InterruptedException
{
final int BUFFER_SIZES=4096;
ServletContext context=request.getServletContext();
String savePath="/tmp/";//PDF file Generate Path
String fileName="PDFFileName"; //Pdf file name
FileInputStream inputStream=null;
BufferedInputStream bufferedInputStream=null;
OutputStream outputStream=null;
printApp(id,fileName);
Thread.sleep(1000);
printApp(id,fileName);
File download=new File(savePath+fileName+".pdf");
while(!download.canRead())
{
Thread.sleep(1000);
printApp(id,fileName);
download=new File(savePath+fileName+".pdf");
}
if(download.canRead()){//if the file can read
try{
Thread.sleep(1000);
inputStream=new FileInputStream(download);
bufferedInputStream=new BufferedInputStream(inputStream);
String mimeType = context.getMimeType(savePath+fileName+".pdf");
if (mimeType == null) {
mimeType = "application/octet-stream";
}
System.out.println("MIME type: " + mimeType);
response.setContentType(mimeType);
response.setContentLength((int)download.length());
String headerKey="Content-Disposition";
String headerValue=String.format("attachment;filename=\"%s\"", download.getName());
response.setHeader(headerKey, headerValue);
outputStream=response.getOutputStream();
byte[] buffer=new byte[BUFFER_SIZES];
int bytesRead=-1;
while ((bytesRead = bufferedInputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
}catch(Exception e)
{
e.printStackTrace();
}
finally
{
try{
if(inputStream!=null)inputStream.close();
if(bufferedInputStream!=null)bufferedInputStream.close();
if(outputStream!=null)outputStream.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
}
public void printApp(String id,String fileName)
{
try{
String urlPath="http://localhost:8080/proj";
urlPath+="/genApp.htm?id="+id;//generate url to execute wkhtmltopdf
String wxpath="/home/exm/wkhtmltopdf";//the path where wkhtmltopdf located
String save="/tmp/"+fileName+".pdf";//File save Pathname
Process process=null;
process=Runtime.getRuntime().exec(wxpath+" "+urlPath+" "+save);
}catch(Exception e)
{}
}
@RequestMapping(value="/genApp.htm",method=RequestMethod.GET)
public String getApplicationPDF(HttpServletRequest request,HttpSession session,@RequestParam String id)
{
UDets uDets=uService.getAllById(Long.parseLong(id));//Methods to get details
request.setAttribute("uDets",uDets );
return "makeApp";//Name of the jsp page
}
In my code I have use Thread.sleep(1000) and printApp(id,fileName) method three times , since sometime wkhtmltopdf fail to generate pdf in certain time and then probability of downloading 0KB file is more. I haven't share the jsp page since the jsp page contain simple jsp page code of lots of line (the size of the generated pdf file is two page).
So the problem is what should I change in my code so that the pdf file generated and download without a failure also in heavy load in server.
If there is any best procedure or idea please share.
I don't like to use itext, since the jsp page contain complex design. Any advise is also appreciable and also thanks in advance.
I would say that your code is flawed not just a little but big time. You are checking if a file can be read, if not you start again a proces writing to the same file (at least twice). At some time you will endup with multiple processes trying to write to the same file, resulting in strange behavior.
I would refactor the printApp method to return the Process it created. Then call waitFor on that process. If it returns 0 and doesn't get interrupted it completed successfully and you should be able to download the file.
@RequestMapping(value="/dwn.htm",method=RequestMethod.GET)
public void dwAppFm(HttpSession session,HttpServletRequest request,HttpServletResponse response,@RequestParam String id) throws IOException,InterruptedException
{
String savePath="/tmp/";//PDF file Generate Path
String fileName="PDFFileName.pdf"; //Pdf file name
File download = new File(savePath, fileName);
try {
Process process = printApp(id, download.getPath());
int status = process.waitFor();
if (status == 0) {
response.setContentType("application/pdf");
response.setContentLength((int)download.length());
String headerKey="Content-Disposition";
String headerValue=String.format("attachment;filename=\"%s\"", download.getName());
StreamUtils.copy(new FileInputStream(download), response.getOutputStream())
} else {
// do something if it fails.
}
} catch (IOException ioe) {
// Do something to handle exception
} catch (InterruptedException ie) {
// Do something to handle exception
}
}
}
public Process printApp(String id, String pdf) throws IOException {
String urlPath="http://localhost:8080/proj";
urlPath+="/genApp.htm?id="+id;//generate url to execute wkhtmltopdf
String wxpath="/home/exm/wkhtmltopdf";//the path where wkhtmltopdf located
String command = wxpath+" "+urlPath+" "+pdf;
return Runtime.getRuntime().exec(command);
}
Something like the code above should to the trick.
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