Input and Output binary streams using JERSEY

Question

I m using Jersey to implement a RESTful API that is primarily retrieve and serve JSON encoded data  But I have some situations where I need to accomplish the following    Export downloadable documents  such as PDF  XLS  ZIP  or other binary files  Retrieve multipart data  such some JSON plus an uploaded XLS file   I have a single-page JQuery-based web client that creates AJAX calls to this web service  At the moment  it doesn t do form submits  and uses GET and POST  with a JSON object   Should I utilize a form post to send data and an attached binary file  or can I create a multipart request with JSON plus binary file   My application s service layer currently creates a ByteArrayOutputStream when it generates a PDF file  What is the best way to output this stream to the client via Jersey  I ve created a MessageBodyWriter  but I don t know how to use it from a Jersey resource  Is that the right approach   I ve been looking through the samples included with Jersey  but haven t found anything yet that illustrates how to do either of these things  If it matters  I m using Jersey with Jackson to do Object- JSON without the XML step and am not really utilizing JAX-RS

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I m using this code to export excel  xlsx  file   Apache Poi   in jersey as an attachement    GET  Path    id  contributions excel    Produces  application vnd openxmlformats-officedocument spreadsheetml sheet   public Response exportExcel  PathParam  id   Long id   throws Exception         Resource resource   new ClassPathResource   xls template xlsx         final InputStream inp   resource getInputStream        final Workbook wb   WorkbookFactory create inp       Sheet sheet   wb getSheetAt 0        Row row   CellUtil getRow 7  sheet       Cell cell   CellUtil getCell row  0       cell setCellValue  TITRE TEST                    StreamingOutput stream   new StreamingOutput             public void write OutputStream output  throws IOException  WebApplicationException               try                   wb write output                 catch  Exception e                    throw new WebApplicationException e                                        return Response ok stream  header  content-disposition   attachment  filename   export xlsx   build

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Using Jersey 2 16 File download is very easy   Below is the example for the ZIP file   GET  Path  zipFile    Produces  application zip   public Response getFile         File f   new File ZIP FILE PATH        if   f exists              throw new WebApplicationException 404              return Response ok f               header  Content-Disposition                        attachment  filename server zip   build

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I found the following helpful to me and I wanted to share in case it helps you or someone else  I wanted something like MediaType PDF TYPE  which doesn t exist  but this code does the same thing   DefaultMediaTypePredictor CommonMediaTypes          getMediaTypeFromFileName  anything pdf     See http   jersey java net nonav apidocs 1 1 0-ea contribs jersey-multipart com sun jersey multipart file DefaultMediaTypePredictor CommonMediaTypes html  In my case I was posting a PDF document to another site   FormDataMultiPart p   new FormDataMultiPart    p bodyPart new FormDataBodyPart FormDataContentDisposition          name  fieldKey   fileName  document pdf   build            new File  path to document pdf            DefaultMediaTypePredictor CommonMediaTypes                  getMediaTypeFromFileName  document pdf        Then p gets passed as the second parameter to post     This link was helpful to me in putting this code snippet together  http   jersey 576304 n2 nabble com Multipart-Post-td4252846 html

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This worked fine with me url http   example com rest muqsith get-file filePath C  Users I066807 Desktop test xml   GET  Produces   MediaType APPLICATION OCTET STREAM     Path   get-file   public Response getFile  Context HttpServletRequest request      String filePath   request getParameter  filePath       if filePath    null  amp  amp      equals filePath            File file   new File filePath           StreamingOutput stream   null          try           final InputStream in   new FileInputStream file           stream   new StreamingOutput                 public void write OutputStream out  throws IOException  WebApplicationException                   try                       int read   0                          byte   bytes   new byte 1024                            while   read   in read bytes      -1                                out write bytes  0  read                                               catch  Exception e                        throw new WebApplicationException e                                                    catch  FileNotFoundException e            e printStackTrace                  return Response ok stream  header  content-disposition   attachment  filename     file getName    build                  return Response ok  file path null   build

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Another sample code where you can upload a file to the REST service  the REST service zips the file  and the client downloads the zip file from the server   This is a good example of using binary input and output streams using Jersey    https   stackoverflow com a 32253028 15789  This answer was posted by me in another thread  Hope this helps

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I had to return a rtf file and this worked for me      create a byte array of the file in correct format byte   docStream   createDoc fragments     return Response              ok docStream  MediaType APPLICATION OCTET STREAM               header  content-disposition   attachment  filename   doc rtf                build

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I have been composing my Jersey 1 17 services the following way   FileStreamingOutput  public class FileStreamingOutput implements StreamingOutput        private File file       public FileStreamingOutput File file            this file   file              Override     public void write OutputStream output              throws IOException  WebApplicationException           FileInputStream input   new FileInputStream file           try               int bytes              while   bytes   input read       -1                    output write bytes                           catch  Exception e                throw new WebApplicationException e             finally               if  output    null  output close                if  input    null  input close                         GET   GET  Produces  application pdf   public StreamingOutput getPdf  QueryParam value  name   String pdfFileName        if  pdfFileName    null          throw new WebApplicationException Response Status BAD REQUEST       if   pdfFileName endsWith   pdf    pdfFileName   pdfFileName     pdf        File pdf   new File Settings basePath  pdfFileName       if   pdf exists            throw new WebApplicationException Response Status NOT FOUND        return new FileStreamingOutput pdf       And the client  if you need it   Client  private WebResource resource   public InputStream getPDFStream String filename  throws IOException       ClientResponse response   resource path  pdf   queryParam  name   filename           type  application pdf   get ClientResponse class       return response getEntityInputStream

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This example shows how to publish log files in JBoss through a rest resource  Note the get method uses the StreamingOutput interface to stream the content of the log file    Path   logs     RequestScoped public class LogResource    private static final Logger logger   Logger getLogger LogResource class getName      Context private UriInfo uriInfo  private static final String LOG PATH    jboss server log dir    public void pipe InputStream is  OutputStream os  throws IOException       int n      byte   buffer   new byte 1024       while   n   is read buffer    gt  -1            os write buffer  0  n        Don t allow any extra bytes to creep in  final write           os close        GET  Path   logFile     Produces  text plain   public Response getLogFile  PathParam  logFile   String logFile  throws URISyntaxException       String logDirPath   System getProperty LOG PATH       try           File f   new File logDirPath         logFile           final FileInputStream fStream   new FileInputStream f           StreamingOutput stream   new StreamingOutput                  Override             public void write OutputStream output  throws IOException  WebApplicationException                   try                       pipe fStream  output                     catch  Exception e                        throw new WebApplicationException e                                                      return Response ok stream  build          catch  Exception e            return Response status Response Status CONFLICT  build              POST  Path   logFile    public Response flushLogFile  PathParam  logFile   String logFile  throws URISyntaxException       String logDirPath   System getProperty LOG PATH       try           File file   new File logDirPath         logFile           PrintWriter writer   new PrintWriter file           writer print              writer close            return Response ok   build          catch  Exception e            return Response status Response Status CONFLICT  build

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Here s another example  I m creating a QRCode as a PNG via a  ByteArrayOutputStream  The resource returns a Response object  and the stream s data is the entity   To illustrate the response code handling  I ve added handling of cache headers  If-modified-since  If-none-matches  etc     Path   externalId  png    GET  Produces   image png    public Response getAsImage  PathParam  externalId   String externalId            Context Request request  throws WebApplicationException        ByteArrayOutputStream stream   new ByteArrayOutputStream           do something with externalId  maybe retrieve an object from the        db  then calculate data  size  expirationTimestamp  etc      try              create a QRCode as PNG from data              BitMatrix bitMatrix   new QRCodeWriter   encode                  data                   BarcodeFormat QR CODE                   size                   size                    MatrixToImageWriter writeToStream bitMatrix   png   stream          catch  Exception e               ExceptionMapper will return HTTP 500          throw new WebApplicationException  Something went wrong                  CacheControl cc   new CacheControl        cc setNoTransform true       cc setMustRevalidate false       cc setNoCache false       cc setMaxAge 3600        EntityTag etag   new EntityTag HelperBean md5 data         Response ResponseBuilder responseBuilder   request evaluatePreconditions              updateTimestamp              etag            if  responseBuilder    null               Preconditions are not met  returning HTTP 304  not-modified          return responseBuilder                  cacheControl cc                   build               Response response   Response              ok                cacheControl cc               tag etag               lastModified updateTimestamp               expires expirationTimestamp               type  image png                entity stream toByteArray                 build        return response         Please don t beat me up in case stream toByteArray   is a no-no memory wise    It works for my  lt 1KB PNG files

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I managed to get a ZIP file or a PDF file by extending the StreamingOutput object  Here is some sample code    Path  PDF-file pdf     GET  Produces   application pdf    public StreamingOutput getPDF   throws Exception       return new StreamingOutput             public void write OutputStream output  throws IOException  WebApplicationException               try                   PDFGenerator generator   new PDFGenerator getEntity                     generator generatePDF output                 catch  Exception e                    throw new WebApplicationException e                                      The PDFGenerator class  my own class for creating the PDF  takes the output stream from the write method and writes to that instead of a newly created output stream    Don t know if it s the best way to do it  but it works

[java] Input and Output binary streams using JERSEY?

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