Fix encoding issue in SpringEncoder for binary data (#1699)

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/support/SpringEncoder.java

@@ -28,6 +28,7 @@ import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpOutputMessage;
 import org.springframework.http.MediaType;
+import org.springframework.http.converter.ByteArrayHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 
 import feign.RequestTemplate;
@@ -95,8 +96,12 @@ public class SpringEncoder implements Encoder {
 					// with the modified headers
 					request.headers(getHeaders(outputMessage.getHeaders()));
 
-					request.body(outputMessage.getOutputStream().toByteArray(),
-							Charset.forName("UTF-8")); // TODO: set charset
+					// do not use charset for binary data
+					if (messageConverter instanceof ByteArrayHttpMessageConverter) {
+						request.body(outputMessage.getOutputStream().toByteArray(), null);
+					} else {
+						request.body(outputMessage.getOutputStream().toByteArray(), Charset.forName("UTF-8"));
+					}
 					return;
 				}
 			}

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/feign/support/SpringEncoderTests.java

@@ -2,10 +2,12 @@ package org.springframework.cloud.netflix.feign.support;
 
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.nullValue;
 import static org.junit.Assert.assertThat;
 
 import java.io.IOException;
 import java.lang.reflect.Type;
+import java.nio.charset.Charset;
 import java.util.Collection;
 
 import org.junit.Test;
@@ -63,6 +65,20 @@ public class SpringEncoderTests {
 
 		String header = contentTypeHeader.iterator().next();
 		assertThat("content type header is wrong", header, is("application/mytype"));
+		
+		assertThat("request charset is null", request.charset(), is(notNullValue()));
+		assertThat("request charset is wrong", request.charset(), is(Charset.forName("UTF-8")));
+	}
+
+	@Test
+	public void testBinaryData() {
+		SpringEncoder encoder = this.context.getInstance("foo", SpringEncoder.class);
+		assertThat(encoder, is(notNullValue()));
+		RequestTemplate request = new RequestTemplate();
+
+		encoder.encode("hi".getBytes(), null, request);
+
+		assertThat("request charset is not null", request.charset(), is(nullValue()));
 	}
 	
 	class MediaTypeMatcher extends ArgumentMatcher<MediaType> {
@@ -129,8 +145,11 @@ public class SpringEncoderTests {
 
 			@Override
 			public boolean canWrite(Class<?> clazz, MediaType mediaType) {
+				if (clazz == String.class) {
 					return true;
 				}
+				return false;
+			}
 
 			@Override
 			protected void writeInternal(Object o, Type type,