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.
Related
I am still searching around this subject, but I cannot find a simple solution, and I don't sure it doesn't exist.
Part 1
I have a service on my application that's generating an excel doc, by the dynamic DB data.
public static void
notiSubscribersToExcel(List<NotificationsSubscriber>
data) {
//generating the file dynamically from DB's data
String prefix = "./src/main/resources/static";
String directoryName = prefix + "/documents/";
String fileName = directoryName + "subscribers_list.xlsx";
File directory = new File(directoryName);
if (! directory.exists()){
directory.mkdir();
// If you require it to make the entire directory path including parents,
// use directory.mkdirs(); here instead.
}
try (OutputStream fileOut = new FileOutputStream(fileName)) {
wb.write(fileOut);
fileOut.close();
wb.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Part 2
I want to access it from the browser, so when I call it will get downloaded.
I know that for the static content, all I need to do is to call to the file, from the browser like that:
http://localhost:8080/documents/myfile.xlsx
After I would be able to do it, all I need is to create link to this url from my client app.
The problem -
Currently if I call to the file as above, it will download only the file which have been there in the compiling stage, but if I am generating a new files after the app is running the content won't be available.
It seems that the content is (as it's called) "static" and cannot be changed after startup.
So my question is
is there is a way to define a folder on the app structure that will be dynamic? I just want to access the new generated file.
BTW I found this answer and others which doing configuration methods, or web services, but I don't want all this. And I have tried some of them, but the result is the same.
FYI I don't bundle my client app with the server app, I run them from different hosts
The problem is to download the file with the dynamic content from a Spring app.
This can be solved with Spring BOOT. Here is the solution as shown in this illustration - when i click Download report, my app generates a dynamic Excel report and its downloaded to the browser:
From a JS, make a get request to a Spring Controller:
function DownloadReport(e){
//Post the values to the controller
window.location="../report" ;
}
Here is the Spring Controller GET Method with /report:
#RequestMapping(value = ["/report"], method = [RequestMethod.GET])
#ResponseBody
fun report(request: HttpServletRequest, response: HttpServletResponse) {
// Call exportExcel to generate an EXCEL doc with data using jxl.Workbook
val excelData = excel.exportExcel(myList)
try {
// Download the report.
val reportName = "ExcelReport.xls"
response.contentType = "application/vnd.ms-excel"
response.setHeader("Content-disposition", "attachment; filename=$reportName")
org.apache.commons.io.IOUtils.copy(excelData, response.outputStream)
response.flushBuffer()
} catch (e: Exception) {
e.printStackTrace()
}
}
This code is implemented in Kotlin - but you can implement it as easily in Java too.
I've been trying to save a JSON (currently, it's simply a generic file) to my device's internal storage. I've looked at tons of examples that look exactly like what I've written, but I can never find the file on my device.
Code to save file
public void saveJSONStringToFile(String json) {
FileOutputStream outfile = null;
String filename = "json_test.json";
try {
outfile = openFileOutput(filename, this.MODE_PRIVATE);
outfile.write(json.getBytes());
outfile.close();
} catch (Exception e) {
e.printStackTrace();
}
}
I know that it's not working because I've also implemented code to retrieve that file and the app just hangs when I try that, implying that it's looking for something that isn't there.
I'm struggling with getting file upload/download to work properly in Play framework 2.2.2. I have a Student class with a field called "cv". It's annotated with #Lob, like this:
#Lob
public byte[] cv;
Here are the upload and download methods:
public static Result upload() {
MultipartFormData body = request().body().asMultipartFormData();
FilePart cv = body.getFile("cv");
if (cv != null) {
filenameCV = cv.getFilename();
String contentType = cv.getContentType();
File file = cv.getFile();
Http.Session session = Http.Context.current().session();
String studentNr = session.get("user");
Student student = Student.find.where().eq("studentNumber", studentNr).findUnique();
InputStream is;
try {
is = new FileInputStream(file);
student.cv = IOUtils.toByteArray(is);
} catch (IOException e) {
Logger.debug("Error converting file");
}
student.save();
flash("ok", "Vellykket! Filen " + filenameCV + " ble lastet opp til din profil");
return redirect(routes.Profile.profile());
} else {
flash("error", "Mangler fil");
return redirect(routes.Profile.profile());
}
}
public static Result download() {
Http.Session session = Http.Context.current().session();
Student student = Student.find.where().eq("studentNumber", session.get("user")).findUnique();
File f = new File("/tmp/" +filenameCV);
FileOutputStream fos;
try {
fos = new FileOutputStream(f);
fos.write(student.cv);
fos.flush();
fos.close();
} catch(IOException e) {
}
return ok(f);
}
The file seems to be correctly saved to the database (the cv field is populated with data, but it's obviously cryptic to me so I don't know for sure that the content is what it's supposed to be)
When I go to my website and click the "Download CV" link (which runs the download action), the file gets downloaded but can't be opened - saying the PDF viewer can't recognize the file etc. (Files uploaded have to be PDF)
Any ideas on what might be wrong?
Don't keep your files in DB, filesystem is much better for that! Save uploaded file on the disk with some unique name, then in your database keep only path to the file as a String!
It's cheaper in longer run (as said many times)
It's easier to handle downloads, i.e. in Play all you need to serve PDF is:
public static Result download() {
File file = new File("/full/path/to/your.pdf");
return ok(file);
}
it will set proper headers, like Content-Disposition, Content-Length and Content-Type not only for PDFs
I am uploading file using spring MVC and jquery. Inside my class method I have written
#RequestMapping(value="attachFile", method=RequestMethod.POST)
public #ResponseBody List<FileAttachment> upload(
#RequestParam("file") MultipartFile file,
HttpServletRequest request,
HttpSession session) {
String fileName = null;
InputStream inputStream = null;
OutputStream outputStream = null;
//Save the file to a temporary location
ServletContext context = session.getServletContext();
String realContextPath = context.getRealPath("/");
fileName = realContextPath +"/images/"+file.getOriginalFilename();
//File dest = new File(fileName);
try {
//file.transferTo(dest);
inputStream = file.getInputStream();
outputStream = new FileOutputStream(fileName);
inputStream.close();
outputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Its uploading the file correctly I am using
ServletContext context = session.getServletContext();
String realContextPath = context.getRealPath("/");
to get the path. My first question is , Is this the correct way to get the path and it stores the file somewhere at
workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/myproject/images
and when I am trying to display this image on my jsp page using the following code
<img src="<%=request.getRealPath("/") + "images/images.jpg" %>" alt="Upload Image" />
It does not display the image, Its generating the following html
<img src="/home/name/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/myproject/images/images.jpg" alt="Upload Image">
Am I doing the things right? In my project I have to upload large number of files everyday.
Please let me know if you need anything else to understand my question
It will be better if you upload your files in some directory by absolute path(e.g. C:\images\) instead of relative (your approach). Usually, web apps runs on linux mathines on production and it is good practice to make save path configurable.
Create some application property which will holds save path for files(in xml or property file).
I'm creating a Java application using Netbeans. From the 'Help' Menu item, I'm required to open a PDF file. When I run the application via Netbeans, the document opens, but on opening via the jar file, it isn't opening. Is there anything that can be done?
m_aboutItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Runtime rt = Runtime.getRuntime();
URL link2=getClass().getResource("/newpkg/Documentation.pdf");
String link=link2.toString();
link=link.substring(6);
System.out.println(link);
System.out.println(link2);
String link3="E:/new/build/classes/newpkg/Documentation.pdf";
try {
Process proc = rt.exec("rundll32.exe url.dll,FileProtocolHandler " + link3);
} catch (IOException ex) {
Logger.getLogger(Menubar1.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
The two outputs are as follows:
E:/new/build/classes/newpkg/Documentation.pdf
file:/E:/new/build/classes/newpkg/Documentation.pdf
Consider the above code snippet. On printing 'link',we can see that it is exactly same as the hard coded 'link3'. On using the hard coded 'link3' , the PDF file gets opened from jar application. But when we use link, though it is exactly same as 'link3', the PDF doesn't open.
This is most likely related to the incorrect PDF resource loading. In the IDE you have the PDF file either as part of the project structure or with a directly specified relative path. When a packaged application is running it does not see the resource.
EDIT:
Your code reveals the problem as I have described. The following method could be used to properly identify resource path.
public static URL getURL(final String pathAndFileName) {
return Thread.currentThread().getContextClassLoader().getResource(pathAndFileName);
}
Pls refer to this question, which might provide additional information.
Try out this:
m_aboutItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (Desktop.isDesktopSupported()) {
Desktop desktop = Desktop.getDesktop();
URL link2=Menubar1.class.getResource("/newpkg/Documentation.pdf");
String link=link2.toString();
link=link.substring(6);
System.out.println(link);
File file=new File(link);
System.out.println(file);
try {
desktop.open(file);
} catch (IOException ex) {
Logger.getLogger(Menubar1.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
});