Spring TestRestTemplate POST and PUT not working when adding Netty as a dependency

Question

When adding

    compile 'io.netty:netty-all:4.1.6.Final'

as a dependency to my Spring Boot project all my unit tests using TestRestTemplate.postForObject(...) and TestRestTemplate.put(...) start to fail. It seems the request body isn't transmitted because I get the following error

Failed to read HTTP message:... HttpMessageNotReadableException: Required request body is missing

The service is still working and accepts POST and PUT requests. I checked that using curl. TestRestTemplate.getForObject(...) on the other hand is still working. Using a normal RestTemplate for POST and PUT is also working.

I tried to configure the TestRestTemplate ( right solution, wrong implementation -> see my answer )

@TestConfiguration static class TestConfig { @Bean RestTemplateBuilder restTemplateBuilder() { RestTemplateBuilder restTemplateBuilder = new RestTemplateBuilder() restTemplateBuilder.detectRequestFactory(false) restTemplateBuilder.requestFactory(new SimpleClientHttpRequestFactory()) return restTemplateBuilder } }

with no effect. I also tried to use Netty4ClientHttpRequestFactory which didn't work either. I tried to configure the HttpMessageConverter using the GsonHttpMessageConverter for example... no effect.

Answer 1

TestRestTemplate isn't working because Spring Boot configures it to use Netty4ClientHttpRequestFactory when it finds Netty on the classpath and the Netty4ClientHttpRequestFactory doesn't seem to work.

See https://github.com/spring-projects/spring-boot/issues/7240 and https://jira.spring.io/browse/SPR-14860

To make TestRestTemplate.postForObject(...) and TestRestTemplate.put(...) I had to provide a RestTemplateBuilder @Bean and configure it to use SimpleClientHttpRequestFactory . The RestTemplateBuilder @Bean in the question has a few errors. It's supposed to look like this

@TestConfiguration
static class TestConfig {
    @Bean
    public RestTemplateBuilder restTemplateBuilder() {
        return new RestTemplateBuilder().detectRequestFactory(false).requestFactory(SimpleClientHttpRequestFactory.class);
    }
}