How to return a PNG image from Jersey REST service method to the browser

Question

I have a web server running with Jersey REST resources up and I wonder how to get an image png reference for the browsers img tag  after submitting a Form or getting an Ajax response  The image processing code for adding graphics is working  just need to return it somehow   Code    POST  Path   fullsize     Consumes MediaType MULTIPART FORM DATA   Produces  image png      Would need to replace void public void getFullImage  FormDataParam  photo   InputStream imageIS                            FormDataParam  submit   String extra           BufferedImage image   ImageIO read imageIS                  image processing              image processing        return ImageIO              Cheers

User · Accepted Answer

I m not convinced its a good idea to return image data in a REST service  It ties up your application server s memory and IO bandwidth  Much better to delegate that task to a proper web server that is optimized for this kind of transfer  You can accomplish this by sending a redirect to the image resource  as a HTTP 302 response with the URI of the image   This assumes of course that your images are arranged as web content   Having said that  if you decide you really need to transfer image data from a web service you can do so with the following  pseudo  code    Path   whatever    Produces  image png   public Response getFullImage             BufferedImage image             ByteArrayOutputStream baos   new ByteArrayOutputStream        ImageIO write image   png   baos       byte   imageData   baos toByteArray            uncomment line below to send non-streamed        return Response ok imageData  build            uncomment line below to send streamed        return Response ok new ByteArrayInputStream imageData   build        Add in exception handling  etc etc

User · Answer

I built a general method for that with following features    returning  not modified  if the file hasn t been modified locally  a Status NOT MODIFIED is sent to the caller  Uses Apache Commons Lang using a file stream object instead of reading the file itself   Here the code   import org apache commons lang3 time DateUtils  import org slf4j Logger  import org slf4j LoggerFactory   private static final Logger logger   LoggerFactory getLogger Utils class     GET  Path  16x16    Produces  image png   public Response get16x16PNG  HeaderParam  If-Modified-Since   String modified        File repositoryFile   new File  c  temp myfile png        return returnFile repositoryFile  modified                 Sends the file if modified and  not modified  if not modified    future work may put each file with a unique id in a separate folder in tomcat        use that static URL for each file        if file is modified  URL of file changes        - gt  client always fetches correct file             method header for calling method public Response getXY  HeaderParam  If-Modified-Since   String modified            param file to send     param modified - HeaderField  If-Modified-Since  - may be  null      return Response to be sent to the client     public static Response returnFile File file  String modified        if   file exists              return Response status Status NOT FOUND  build                  do we really need to send the file or can send  not modified       if  modified    null            Date modifiedDate   null              we have to switch the locale to ENGLISH as parseDate parses in the default locale         Locale old   Locale getDefault            Locale setDefault Locale ENGLISH           try               modifiedDate   DateUtils parseDate modified  org apache http impl cookie DateUtils DEFAULT PATTERNS             catch  ParseException e                logger error e getMessage    e                     Locale setDefault old            if  modifiedDate    null                   modifiedDate does not carry milliseconds  but fileDate does                therefore we have to do a range-based comparison                1000 milliseconds   1 second             if  file lastModified  -modifiedDate getTime    lt  DateUtils MILLIS PER SECOND                    return Response status Status NOT MODIFIED  build                                                 we really need to send the file      try           Date fileDate   new Date file lastModified             return Response ok new FileInputStream file   lastModified fileDate  build          catch  FileNotFoundException e            return Response status Status NOT FOUND  build                  copied from org apache http impl cookie DateUtils  Apache 2 0 License              Date format pattern used to parse HTTP date headers in RFC 1123 format      public static final String PATTERN RFC1123    EEE  dd MMM yyyy HH mm ss zzz           Date format pattern used to parse HTTP date headers in RFC 1036 format      public static final String PATTERN RFC1036    EEEE  dd-MMM-yy HH mm ss zzz           Date format pattern used to parse HTTP date headers in ANSI C     lt code gt asctime   lt  code gt  format      public static final String PATTERN ASCTIME    EEE MMM d HH mm ss yyyy    public static final String   DEFAULT PATTERNS   new String         PATTERN RFC1036      PATTERN RFC1123      PATTERN ASCTIME      Note that the Locale switching does not seem to be thread-safe  I think  it s better to switch the locale globally  I am not sure about the side-effects though

User · Answer

If you have a number of image resource methods  it is well worth creating a MessageBodyWriter to output the BufferedImage    Produces    image png    image jpg      Provider public class BufferedImageBodyWriter implements MessageBodyWriter lt BufferedImage gt        Override   public boolean isWriteable Class lt   gt  type  Type type1  Annotation   antns  MediaType mt        return type    BufferedImage class          Override   public long getSize BufferedImage t  Class lt   gt  type  Type type1  Annotation   antns  MediaType mt        return -1     not used in JAX-RS 2         Override   public void writeTo BufferedImage image  Class lt   gt  type  Type type1  Annotation   antns  MediaType mt  MultivaluedMap lt String  Object gt  mm  OutputStream out  throws IOException  WebApplicationException       ImageIO write image  mt getSubtype    out            This MessageBodyWriter will be used automatically if auto-discovery is enabled for Jersey  otherwise it needs to be returned by a custom Application sub-class  See JAX-RS Entity Providers for more info   Once this is set up  simply return a BufferedImage from a resource method and it will be be output as image file data    Path   whatever    Produces   image png    image jpg    public Response getFullImage          BufferedImage image          return Response ok image  build        A couple of advantages to this approach    It writes to the response OutputSteam rather than an intermediary BufferedOutputStream It supports both png and jpg output  depending on the media types allowed by the resource method

User · Answer

in regard of answer from  Perception  its true to be very memory-consuming when working with byte arrays  but you could also simply write back into the outputstream   Path   picture   public class ProfilePicture      GET    Path   thumbnail      Produces  image png     public StreamingOutput getThumbNail         return new StreamingOutput            Override       public void write OutputStream os  throws IOException  WebApplicationException                 read your stream and write into os

[java] How to return a PNG image from Jersey REST service method to the browser

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