Adding support for application/octet-stream in RestController (Spring Boot) - java version

WebConfig.java

package mycompany.myappp.config;

import org.apache.commons.io.IOUtils;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.converter.AbstractHttpMessageConverter;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * Configure Spring Boot to allow upload of octet-stream.
 */
@Configuration
public class WebConfig extends WebMvcConfigurationSupport {

    @Override
    protected void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(new AbstractHttpMessageConverter<InputStream>(MediaType.APPLICATION_OCTET_STREAM) {
            protected boolean supports(Class<?> clazz) {
                return InputStream.class.isAssignableFrom(clazz);
            }

            protected InputStream readInternal(Class<? extends InputStream> clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
                return inputMessage.getBody();
            }

            protected void writeInternal(InputStream inputStream, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {
                IOUtils.copy(inputStream, outputMessage.getBody());
            }
        });
        super.configureMessageConverters(converters);
    }
}

Thanks a lot for an idea of how it works!

This implementation removes default convertors (for example, Jakson's for application/json). To save default convertors, add this line before call super.configureMessageConverters(converters); on line 39.

        addDefaultHttpMessageConverters(converters);