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Upgrading S3Client to S3AsyncClient how to get Publisher<ByteBuffer>?

I am upgrading S3Client in aws cloud service to S3AsyncClient.
I have this function to convert to async:
public PutObjectResponse uploadFileByUrl(String fileUrl, String builderId, PbModel category, String categoryId)
URL url = new URL(fileUrl);
String[] fileNameArray = url.getFile().split("\\.");
var uniqueFileName = prepareFileName(fileNameArray[fileNameArray.length -1]);
URLConnection connection = url.openConnection();
long contentSize = connection.getContentLengthLong();
InputStream inputStream = connection.getInputStream();
return s3Client.putObject(myObjectRequestBuild, RequestBody.fromInputStream(inputStream, contentSize));
}
I have this function to convert to async:
public CompletableFuture<PutObjectResponse> uploadFileByUrl(String fileUrl, String builderId, PbModel category, String categoryId)
URL url = new URL(fileUrl);
String[] fileNameArray = url.getFile().split("\\.");
var uniqueFileName = prepareFileName(fileNameArray[fileNameArray.length -1]);
URLConnection connection = url.openConnection();
long contentSize = connection.getContentLengthLong();
InputStream inputStream = connection.getInputStream();
return asyncClient.putObject(myObjectRequestBuild, AsyncRequestBody.fromPublisher(???));
}
As you can see in second method above when I convert the first function above to async I need to use AsyncRequestBody instead of RequestBody.
AsyncRequestBody doesn't have fromInputStream method but it have fromPublisher method that I want to use, the fromPublisher method get as parameter type of Publisher.
So my question is how to convert my inputStream into an Publisher?

AsyncRequestBody doesn't have fromInputStream method
Correct however, it has a plethora of other ways to create an AsyncRequestBody:
fromByteBuffer(ByteBuffer byteBuffer)
fromBytes(byte[] bytes)
fromFile(File file)
fromFile(Path path)
fromPublisher(org.reactivestreams.Publisher<ByteBuffer> publisher)
fromString(String string)
fromString(String string, Charset cs)
Considering the above, you have a few solutions:
Convert the InputStream to a byte array using IOUtils.toByteArray(inputStream) (or in Java 9+, inputStream.readAllBytes()) and then use fromBytes directly
As above but then convert the byte[] to a ByteBuffer using ByteBuffer.wrap(byteArray) and then use fromByteBuffer
Create a new File object specifying a filename, copy the contents of the InputStream to the file's FileOutputStream using IOUtils.copy(), and then use fromFile(File file)
As above but instead of providing the File object, provide its path to fromFile(Path path) after you've written to it's FileOutputStream
Convert the InputSteam to a Publisher<ByteArray> using DataBufferUtils.readByteChannel from the Spring Framework, Akka StreamConverters etc. and then use fromPublisher
Convert the InputStream to a UTF-8 encoded String then use fromString(String string) (no need to specify the Charset if it is UTF-8 encoded)
Convert the InputStream to a non-UTF-8 encoded String then use fromString(String string, Charset cs), specifying the CharSet
Of course, some of the above are plain redundant in your case e.g. fromFile(Path path) is for files that you've already stored & converting the InputSteam to a Publisher<ByteArray> is going to be a pain but I've included all possible solutions for completeness.
I would approach this using solution #1, resulting in the cleanest, simplest code out of the above.
Convert the InputStream to byte[] using inputStream.readAllBytes() and then use AsyncRequestBody.fromBytes(...).
This should work:
public CompletableFuture<PutObjectResponse> uploadFileByUrl(String fileUrl, String builderId, PbModel category, String categoryId)
URL url = new URL(fileUrl);
String[] fileNameArray = url.getFile().split("\\.");
var uniqueFileName = prepareFileName(fileNameArray[fileNameArray.length -1]);
URLConnection connection = url.openConnection();
long contentSize = connection.getContentLengthLong();
InputStream inputStream = connection.getInputStream();
byte[] fileByteArray = inputStream.readAllBytes();
return asyncClient.putObject(myObjectRequestBuild, AsyncRequestBody.fromBytes(fileByteArray));
}

Streaming dynamically created ZIP file with Play Framework

I have a question regarding dynamically creating and streaming ZIP files. I have multiple large files stored on remote HTTP servers (for example Amazon S3).
Now I want the user to download let's say 100 files as one ZIP file.
I could download all 100 files, zip them and stream them to the user, but that would be wasting lots of resources. So my approach is download the first file, stream it to the user, download the next file, stream it to the user and so on.
This is the test code:
public class TestController extends Controller {
public Result test() throws Exception {
InputStream is = getDynamicStreamSomewhere();
response().setContentType("application/zip");
response().setHeader("Content-Disposition", "attachment;filename=test.zip");
return ok(is);
}
private InputStream getDynamicStreamSomewhere() throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ZipOutputStream zos = new ZipOutputStream(baos);
String url1 = "http://www.example.com/largefile1.bin";
String url2 = "http://www.example.com/largefile2.bin";
ZipEntry entry1 = new ZipEntry("file1.bin");
zos.putNextEntry(entry1);
URL website = new URL(url2);
InputStream in = website.openStream();
IOUtils.copy(in, zos);
in.close();
zos.closeEntry();
ZipEntry entr2 = new ZipEntry("file2.bin");
zos.putNextEntry(entr2);
URL websitea = new URL(url1);
InputStream ina = websitea.openStream();
IOUtils.copy(ina, zos);
ina.close();
zos.closeEntry();
return new ByteArrayInputStream(baos.toByteArray());
}
}
But as far as I debugged it, that does not really stream file by file but download everything and then stream it to the user.
What I am missing is something like flushing the output buffer to the user after every file (or maybe after each 4KB block).
I know how to do it with Java servlets, but not with Play Framework. Any help is appreciated!
Thank you!

Download Large file from server using REST template Java Spring MVC

I have a REST service which sends me a large ISO file ,there are no issues in the REST service .
Now I have written a Web application which calls the rest service to get the file ,on the client(web app) side I receive a Out Of memory Exception.Below is my code
HttpHeaders headers = new HttpHeaders();//1 Line
headers.setAccept(Arrays.asList(MediaType.APPLICATION_OCTET_STREAM));//2 Line
headers.set("Content-Type","application/json");//3 Line
headers.set("Cookie", "session=abc");//4 Line
HttpEntity statusEntity=new HttpEntity(headers);//5 Line
String uri_status=new String("http://"+ip+":8080/pcap/file?fileName={name}");//6 Line
ResponseEntity<byte[]>resp_status=rt.exchange(uri_status, HttpMethod.GET, statusEntity, byte[].class,"File5.iso");//7 Line
I receive out of memory exception at 7 line ,I guess i will have to buffer and get in parts ,but dont know how can i get this file from the server ,the size of the file is around 500 to 700 MB .
Can anyone please assist .
Exception Stack:
org.springframework.web.util.NestedServletException: Handler processing failed; nested exception is java.lang.OutOfMemoryError: Java heap space
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:972)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
java.lang.OutOfMemoryError: Java heap space
java.util.Arrays.copyOf(Arrays.java:3236)
java.io.ByteArrayOutputStream.grow(ByteArrayOutputStream.java:118)
java.io.ByteArrayOutputStream.ensureCapacity(ByteArrayOutputStream.java:93)
java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:153)
org.springframework.util.FileCopyUtils.copy(FileCopyUtils.java:113)
org.springframework.util.FileCopyUtils.copyToByteArray(FileCopyUtils.java:164)
org.springframework.http.converter.ByteArrayHttpMessageConverter.readInternal(ByteArrayHttpMessageConverter.java:58)
org.springframework.http.converter.ByteArrayHttpMessageConverter.readInternal(ByteArrayHttpMessageConverter.java:1)
org.springframework.http.converter.AbstractHttpMessageConverter.read(AbstractHttpMessageConverter.java:153)
org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:81)
org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:627)
org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:1)
org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:454)
org.springframework.web.client.RestTemplate.execute(RestTemplate.java:409)
org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:385)
com.pcap.webapp.HomeController.getPcapFile(HomeController.java:186)
My Server Side REST Service Code which is working fine is
#RequestMapping(value = URIConstansts.GET_FILE, produces = { MediaType.APPLICATION_OCTET_STREAM_VALUE}, method = RequestMethod.GET)
public void getFile(#RequestParam(value="fileName", required=false) String fileName,HttpServletRequest request,HttpServletResponse response) throws IOException{
byte[] reportBytes = null;
File result=new File("/home/arpit/Documents/PCAP/dummyPath/"+fileName);
if(result.exists()){
InputStream inputStream = new FileInputStream("/home/arpit/Documents/PCAP/dummyPath/"+fileName);
String type=result.toURL().openConnection().guessContentTypeFromName(fileName);
response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
response.setHeader("Content-Type",type);
reportBytes=new byte[100];//New change
OutputStream os=response.getOutputStream();//New change
int read=0;
while((read=inputStream.read(reportBytes))!=-1){
os.write(reportBytes,0,read);
}
os.flush();
os.close();
}

Here is how I do it. Based on hints from this Spring Jira issue.
RestTemplate restTemplate // = ...;
// Optional Accept header
RequestCallback requestCallback = request -> request.getHeaders()
.setAccept(Arrays.asList(MediaType.APPLICATION_OCTET_STREAM, MediaType.ALL));
// Streams the response instead of loading it all in memory
ResponseExtractor<Void> responseExtractor = response -> {
// Here I write the response to a file but do what you like
Path path = Paths.get("some/path");
Files.copy(response.getBody(), path);
return null;
};
restTemplate.execute(URI.create("www.something.com"), HttpMethod.GET, requestCallback, responseExtractor);
From the aforementioned Jira issue:
Note that you cannot simply return the InputStream from the extractor, because by the time the execute method returns, the underlying connection and stream are already closed.
Update for Spring 5
Spring 5 introduced the WebClient class which allows asynchronous (e.g. non-blocking) http requests. From the doc:
By comparison to the RestTemplate, the WebClient is:
non-blocking, reactive, and supports higher concurrency with less hardware resources.
provides a functional API that takes advantage of Java 8 lambdas.
supports both synchronous and asynchronous scenarios.
supports streaming up or down from a server.
To get WebClient in Spring Boot, you need this dependency:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
For the moment, I'm sticking with RestTemplate because I don't want to pull in another dependency only to get access to WebClient.

As #bernie mentioned you can use WebClient to achieve this:
public Flux<DataBuffer> downloadFileUrl( ) throws IOException {
WebClient webClient = WebClient.create();
// Request service to get file data
return Flux<DataBuffer> fileDataStream = webClient.get()
.uri( this.fileUrl )
.accept( MediaType.APPLICATION_OCTET_STREAM )
.retrieve()
.bodyToFlux( DataBuffer.class );
}
#GetMapping( produces = MediaType.APPLICATION_OCTET_STREAM_VALUE )
public void downloadFile( HttpServletResponse response ) throws IOException
{
Flux<DataBuffer> dataStream = this.downloadFileUrl( );
// Streams the stream from response instead of loading it all in memory
DataBufferUtils.write( dataStream, response.getOutputStream() )
.map( DataBufferUtils::release )
.blockLast();
}
You can still use WebClient even if you don't have Reactive Server stack - Rossen Stoyanchev (a member of Spring Framework team) explains it quite well in the Guide to "Reactive" for Spring MVC Developers presentation. During this presentation, Rossen Stoyanchev mentioned that they thought about deprecating RestTemplate, but they have decided to postpone it after all, but it may still happen in the future!
The main disadvantage of using WebClient so far it's a quite steep learning curve (reactive programming), but I think there is no way to avoid in the future, so better to take a look on it sooner than latter.

This prevents loading the entire request into memory.
SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
requestFactory.setBufferRequestBody(false);
RestTemplate rest = new RestTemplate(requestFactory);
For java.lang.OutOfMemoryError: Java heap space can be solved adding more memory to the JVM:
-Xmxn Specifies the maximum size, in bytes, of the memory allocation pool. This value must a multiple of 1024 greater than 2 MB. Append the
letter k or K to indicate kilobytes, or m or M to indicate megabytes.
The default value is chosen at runtime based on system configuration.
For server deployments, -Xms and -Xmx are often set to the same value.
See Garbage Collector Ergonomics at
http://docs.oracle.com/javase/7/docs/technotes/guides/vm/gc-ergonomics.html
Examples:
-Xmx83886080
-Xmx81920k
-Xmx80m
Probably the problem you have is not strictly related to the request you are trying to execute (download large file) but the memory allocated for the process is not enough.

A better version of above correct answer could be the below code. This method will send download request to another application or service acting as actual source of truth for downloaded information.
public void download(HttpServletRequest req, HttpServletResponse res, String url)
throws ResourceAccessException, GenericException {
try {
logger.info("url::" + url);
if (restTemplate == null)
logger.info("******* rest template is null***********************");
RequestCallback requestCallback = request -> request.getHeaders()
.setAccept(Arrays.asList(MediaType.APPLICATION_OCTET_STREAM, MediaType.ALL));
// Streams the response instead of loading it all in memory
ResponseExtractor<ResponseEntity<InputStream>> responseExtractor = response -> {
String contentDisposition = response.getHeaders().getFirst("Content-Disposition");
if (contentDisposition != null) {
// Temporary location for files that will be downloaded from micro service and
// act as final source of download to user
String filePath = "/home/devuser/fileupload/download_temp/" + contentDisposition.split("=")[1];
Path path = Paths.get(filePath);
Files.copy(response.getBody(), path, StandardCopyOption.REPLACE_EXISTING);
// Create a new input stream from temporary location and use it for downloading
InputStream inputStream = new FileInputStream(filePath);
String type = req.getServletContext().getMimeType(filePath);
res.setHeader("Content-Disposition", "attachment; filename=" + contentDisposition.split("=")[1]);
res.setHeader("Content-Type", type);
byte[] outputBytes = new byte[100];
OutputStream os = res.getOutputStream();
int read = 0;
while ((read = inputStream.read(outputBytes)) != -1) {
os.write(outputBytes, 0, read);
}
os.flush();
os.close();
inputStream.close();
}
return null;
};
restTemplate.execute(url, HttpMethod.GET, requestCallback, responseExtractor);
} catch (Exception e) {
logger.info(e.toString());
throw e;
}
}

You should use multipart file attachment, so the file stream isn't load into memory.
In this example, I use a rest service implemented with Apache CXF.
...
import org.apache.cxf.jaxrs.ext.multipart.Attachment;
...
#Override
#Path("/put")
#Consumes("multipart/form-data")
#Produces({ "application/json" })
#POST
public SyncResponseDTO put( List<Attachment> attachments) {
SyncResponseDTO response = new SyncResponseDTO();
try {
for (Attachment attr : attachments) {
log.debug("get input filestream: " + new Date());
InputStream is = attr.getDataHandler().getInputStream();

Return file from Spring #Controller having OutputStream

I want to return a file from a Spring controller. I already have API that can give me any implementation of OutputStream and then I need to send it to a user.
So the flow is something like that:
getting outputstream -> service passes this outputstream to controller -> controller has to send it to a user
I think I need inputstream to do it and I have also found Apache Commons api feature that looks like this:
IOUtils.copy(InputStream is, OutputStream os)
but the problem is, it converts it to the other side -> not from os to is, but from is to os.
Edit
to be clear, because I see the answers are not hitting right thing:
I use Dropbox api and recieve file in OutputStream and I want this output stream to be sent to user while entering some URL
FileOutputStream outputStream = new FileOutputStream(); //can be any instance of OutputStream
DbxEntry.File downloadedFile = client.getFile("/fileName.mp3", null, outputStream);
Thats why i was talking about converting outputstream to inputstream, but have no idea how to do it. Furthermore, I suppose that there is better way to solve this (maybe return byte array somehow from outputstream)
I was trying to pass servlet outputstream [response.getOutputstream()] through parameter to the method that downloads file from dropbox, but it didnt work, at all
Edit 2
The "flow" of my app is something like this: #Joeblade
User enters url: /download/{file_name}
Spring Controller captures the url and calls the #Service layer to download the file and pass it to that controller:
#RequestMapping(value = "download/{name}", method = RequestMethod.GET)
public void getFileByName(#PathVariable("name") final String name, HttpServletResponse response) throws IOException {
response.setContentType("audio/mpeg3");
response.setHeader("Content-Disposition", "attachment; filename=" + name);
service.callSomeMethodAndRecieveDownloadedFileInSomeForm(name); // <- and this file(InputStream/OutputStream/byte[] array/File object/MultipartFile I dont really know..) has to be sent to the user
}
Now the #Service calls Dropbox API and downloads the file by specified file_name, and puts it all to the OutputStream, and then passes it (in some form.. maybe OutputStream, byte[] array or any other object - I dont know which is better to use) to the controller:
public SomeObjectThatContainsFileForExamplePipedInputStream callSomeMethodAndRecieveDownloadedFileInSomeForm(final String name) throws IOException {
//here any instance of OutputStream - it needs to be passed to client.getFile lower (for now it is PipedOutputStream)
PipedInputStream inputStream = new PipedInputStream(); // for now
PipedOutputStream outputStream = new PipedOutputStream(inputStream);
//some dropbox client object
DbxClient client = new DbxClient();
try {
//important part - Dropbox API downloads the file from Dropbox servers to the outputstream object passed as the third parameter
client.getFile("/" + name, null, outputStream);
} catch (DbxException e){
e.printStackTrace();
} finally {
outputStream.close();
}
return inputStream;
}
Controler recieves the file (I dont know, at all, in which form as I said upper) and passes it then to the user
So the thing is to recieve OutputStream with the downloaded file by calling dropboxClient.getFile() method and then this OutputStream that contains the downloaded file, has to be sent to the user, how to do this?

Get the OutputStream from the HttpServletResponse and write the file to it (in this example using IOUtils from Apache Commons)
#RequestMapping(value = "/download", method = RequestMethod.GET)
public void download(HttpServletResponse response) {
...
InputStream inputStream = new FileInputStream(new File(PATH_TO_FILE)); //load the file
IOUtils.copy(inputStream, response.getOutputStream());
response.flushBuffer();
...
}
Make sure you use a try/catch to close the streams in case of an exception.

The most preferable solution is to use InputStreamResource with ResponseEntity. All you need is set Content-Length manually:
#RequestMapping(value = "/download", method = RequestMethod.GET)
public ResponseEntity download() throws IOException {
String filePath = "PATH_HERE";
InputStream inputStream = new FileInputStream(new File(filePath));
InputStreamResource inputStreamResource = new InputStreamResource(inputStream);
HttpHeaders headers = new HttpHeaders();
headers.setContentLength(Files.size(Paths.get(filePath)));
return new ResponseEntity(inputStreamResource, headers, HttpStatus.OK);
}

You could use the ByteArrayOutputStream and ByteArrayInputStream. Example:
// A ByteArrayOutputStream holds the content in memory
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
// Do stuff with your OutputStream
// To convert it to a byte[] - simply use
final byte[] bytes = outputStream.toByteArray();
// To convert bytes to an InputStream, use a ByteArrayInputStream
ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
You can do the same with other stream pairs. E.g. the file streams:
// Create a FileOutputStream
FileOutputStream fos = new FileOutputStream("filename.txt");
// Write contents to file
// Always close the stream, preferably in a try-with-resources block
fos.close();
// The, convert the file contents to an input stream
final InputStream fileInputStream = new FileInputStream("filename.txt");
And, when using Spring MVC you can definitely return a byte[] that contains your file. Just make sure that you annotate your response with #ResponseBody. Something like this:
#ResponseBody
#RequestMapping("/myurl/{filename:.*}")
public byte[] serveFile(#PathVariable("file"} String file) throws IOException {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
DbxEntry.File downloadedFile = client.getFile("/" + filename, null, outputStream);
return outputStream.toByteArray();
}

I recommend reading this answer
#ResponseBody
#RequestMapping("/photo2", method = RequestMethod.GET, produces = MediaType.IMAGE_JPEG_VALUE)
public byte[] testphoto() throws IOException {
InputStream in = servletContext.getResourceAsStream("/images/no_image.jpg");
return IOUtils.toByteArray(in);
}
answered by michal.kreuzman
I was going to write something similar myself but ofcourse it's already been answered.
If you want to just pass the stream instead of first getting everything in memory you could use this answer
I haven't tested this (not at work) but it looks legit :)
#RequestMapping(value = "report1", method = RequestMethod.GET, produces = "application/pdf")
#ResponseBody
public void getReport1(OutputStream out) {
InputStream in; // retrieve this from wherever you are receiving your stream
byte[] buffer = new byte[1024];
int len;
while ((len = in.read(buffer)) != -1) {
out.write(buffer, 0, len);
}
in.close();
out.flush(); // out.close?
}
The thing is, this is pretty much the same as IOUtils.copy / IOUtils.copyLarge does. line: 2128
Which you say copies the wrong direction.
However first make sure you understand what you ask. If you want to read from an outputstream(object for writing) and write to an input stream (object to read from) then I think what you really want is to write to an object that also supplies a read option.
for that you could use a PipedInputStream and PipedOutputStream. These are connected together so that bytes written to the outputstream are available to be read from the corresponding input stream.
so in the location where you are receiving the bytes I assume you are writing bytes to an outputstream.
there do this:
// set up the input/output stream so that bytes written to writeToHere are available to be read from readFromhere
PipedInputStream readFromHere = new PipedInputStream();
PipedOutputStream writeToHere = new PipedOutputStream(readFromHere);
// write to the outputstream as you like
writeToHere.write(...)
// or pass it as an outputstream to an external method
someMather(writeToHere);
// when you're done close this end.
writeToHere.close();
// then whenever you like, read from the inputstream
IOUtils.copy(readFromHere, out, new byte[1024]);
If you use IOUtils.copy it will continue to read until the outputstream is closed. so make sure that it is already closed before starting (if you run write/read on the same thread) or use another thread to write to the output buffer and close it at the end.
If this is still not what you're looking for then you'll have to refine your question.

The most memory-efficient solution in your case would be to pass the response OutputStream right to the Dropbox API:
#GetMapping(value = "download/{name}")
public void getFileByName(#PathVariable("name") final String name, HttpServletResponse response)
throws IOException, DbxException {
response.setContentType("audio/mpeg3");
response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + name + "\"");
response.setContentLength(filesize); // if you know size of the file in advance
new DbxClient().getFile("/" + name, null, response.getOutputStream());
}
Data read by the API will be sent directly to the user. No additional byte buffer of any type is required.
As for PipedInputStream/PipedOutputStream, they are intended for the blocking communication between 2 threads. PipedOutputStream blocks writing thread after 1024 bytes (by default) until some other thread start reading from the end of the pipe (PipedInputStream).

One thing to keep in mind when writing to the response outputstream is that it is a very good idea to call flush() on whatever writer that you've wrapped it with periodically. The reason for this is that a broken connection (for example caused by a user canceling a download) may not end up throwing an exception for a long time, if ever. This can effectively be a resource leak on your container.

Returning ZipInputStream as a Jax-RS Response object

I am trying to return a ZipInputStream containing two different outputstreams as a javax.ws.rs.core.Response Stream. When I make a web service call to retrieve the stream, I notice that I get an empty stream back.
I have tried returning a GZipInputStream before, and I have received the expected stream on the client side. Could there be an issue with ZipInputStream that prevents it from being returned properly?
I am using javax 2.4 (servlet-api)
This is how my jax-rs service looks like (I have simplified it a bit):
#GET
#Produces({"application/zip", MediaType.APPLICATION_XML})
public Response getZipFiles(#PathParam("id") final Integer id){
//Get required resources here
ByteArrayOutputStream bundledStream = new ByteArrayOutputStream();
ZipOutputStream out = new ZipOutputStream(bundledStream);
out.putNextEntry(new ZipEntry("Item A"));
out.write(outputStream.toByteArray());
out.closeEntry();
out.putNextEntry(new ZipEntry("Item B"));
out.write(defectiveBillOutputStream.toByteArray());
out.closeEntry();
out.close();
bundledStream.close();
ZipInputStream zis = new ZipInputStream(new ByteArrayInputStream(bundledStream.toByteArray()));
return Response.ok(zis).build();
}
And this is the code that calls the service. I am using axis 1.4:
HttpMethodBase getBillGroup = null;
String id = "1234";
String absoluteUrl = baseURL + BASE_SERVICE_PATH.replace("#id#",id) ;
getZip = new GetMethod(absoluteUrl);
HttpClient httpClient = new HttpClient();
try {
httpClient.executeMethod(getZip);
}
catch (Exception e) {
LOGGER.error("Error during retrieval " + e.getMessage());
}
InputStream dataToConvert = getZip.getResponseBodyAsStream();
ZipInputStream in = new ZipInputStream(dataToConvert);
ZipEntry itemA = in.getNextEntry();
//Do more things
On the last line, itemA should have been the first entry added to the stream in the Jax-RS Service, but I am getting a null back. Any idea what might be causing this?

In the first block use a ByteArrayInputStream instead of a ZipInputStream, which iterates complex zip entries.