CODEWITHSUNDEEP
javainputstreamfileinputstreamgzipinputstream
JabberwokyStrollin
JabberwokyStrollin

Reputation: 429

GZIPInputStream works with FileInputStream but not InputStream

I noticed while working with GZIPInputStream that using an InputStream generated from Class.class.getResourceAsStream on a gzipped file causes a

java.util.zip.ZipException: invalid code lengths set

when used in GZIPInputStream, but using a FileInputStream on the same file seems to work fine. Does anyone know what is causing this?

For example:

InputStream is = new FileInputStream("src/main/resources/testFile.gz");
GZIPInputStream zis = new GZIPInputStream(is);
String outputStr = IOUtils.toString(zis, "utf-8");

Successfully generates an output string with the unzipped file data, while:

InputStream is = Class.class.getResourceAsStream("/testFile.gz");
GZIPInputStream zis = new GZIPInputStream(is);
String outputStr = IOUtils.toString(zis, "utf-8");

Generates the ZipException above.

I when I un-gzip the file I am able to get the correct outputString using IOUtils.toString on the InputStream generated either way so I know that the file is being accessed successfully and the issue appears to be with GZIPInputStream its self.

Upvotes: 0

Views: 1113

Answers (1)

JabberwokyStrollin
JabberwokyStrollin

Reputation: 429

It turns out Maven is the culprit behind why using getResourceAsStream was generating a ZipException while FileInputStream was not. The gz files I had under src/main/resources were being copied to target/src/main/resources by Maven, and were subsequently auto corrupted when Maven filtering was applied. FileInputStream was targeting the file under src/main/resources while getResourceAsStream was targeting the file under target/src/main/resources. The solution to the issue was to disable filtering for my resources in the src/main/resources directory as follows.

<resource>
  <directory>src/main/resources</directory>
  <includes>
    <include>**/*</include>
  </includes>
  <filtering>false</filtering>
</resource>

Upvotes: 1

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