Spring integration Unzip transformer throws ReplyRequiredException exception

Question

We would like to decompress a byte array using Spring Integration and are experiencing the following exception upon using unzip-transformer:

org.springframework.integration.handler.ReplyRequiredException: No reply produced by handler 'org.springframework.integration.handler.MessageHandlerChain#1$child#1' ., and its 'requiresReply' property is set to true.,failedMessage=GenericMessage [payload=byte[327] ...

This is the .xml blob we are trying to use for this effort:

int-zip:unzip-transformer result-type="BYTE_ARRAY" expect-single-result="true"/>

The equivalent java code using service-activator works fine for decompression:

ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
GZIPInputStream gzipInputStream;
gzipInputStream = new GZIPInputStream(new ByteArrayInputStream((byte[]) 
message.getPayload()));
IOUtils.copy(gzipInputStream, byteArrayOutputStream);
byteArrayOutputStream.close();
return new String(byteArrayOutputStream.toByteArray(), Charsets.UTF_8);

Is there any way to do the same code using unzip-transformer?

Answer 1

GZIPInputStream ... The Spring Integration ZIP doesn't support GZIP, only regular ZIP with entries. That's how you get that exception:

 if (uncompressedData.isEmpty()) {
                if (logger.isWarnEnabled()) {
                    logger.warn("No data unzipped from payload with message Id " + message.getHeaders().getId());
                }
                unzippedData = null;
            }

Just because the ZipUtil.iterate(InputStream is, ZipEntryCallback action) has nothing to iterate over GZIP payload.