How to parse gzip encoded response with RestTemplate in Spring-Web

Question

After I modified Consuming a RESTful Web Service example to call get users by id from api.stackexchange.com I get JsonParseException:

com.fasterxml.jackson.cor

Answer 1

private String callViaRest(String requestString, Steps step) {
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.TEXT_XML);
    headers.add("Accept-Encoding", "application/gzip");
    HttpEntity<String> entity = new HttpEntity<String>(requestString, headers);

    byte[] responseBytes = jsonRestTemplate
            .exchange("yourUrl", HttpMethod.POST, entity, byte[].class).getBody();
    String decompressed = null;
    try {
        decompressed= new String(CompressionUtil.decompressGzipByteArray(responseBytes),Charsets.UTF_8);
    } catch (IOException e) {
        LOGGER.error("network call failed.", e);
    }
    return decompressed;
}

Answer 2

Replace the default requestFactory with one from Apache HttpClient (which decodes GZIP on the fly):

HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(
            HttpClientBuilder.create().build());
RestTemplate restTemplate = new RestTemplate(clientHttpRequestFactory);

Add Apache Http Client into pom.xml

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <!--Version is not needed when used with Spring Boot parent pom file -->
    <version>4.5.1</version>
</dependency>