From ce8fe48393f8efe101db162fb5afcf46fd2f7d7d Mon Sep 17 00:00:00 2001
From: Chen Qian <chenqian@oppo.com>
Date: Mon, 11 Jan 2021 11:10:03 +0800
Subject: [PATCH] append warn log only when MediaType present (#28)

---
 ...stractResponseBodyReturnValueResolver.java | 24 +++++++++++--------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/restlight-core/src/main/java/esa/restlight/core/resolver/result/AbstractResponseBodyReturnValueResolver.java b/restlight-core/src/main/java/esa/restlight/core/resolver/result/AbstractResponseBodyReturnValueResolver.java
index c978bca3..f2e39be4 100644
--- a/restlight-core/src/main/java/esa/restlight/core/resolver/result/AbstractResponseBodyReturnValueResolver.java
+++ b/restlight-core/src/main/java/esa/restlight/core/resolver/result/AbstractResponseBodyReturnValueResolver.java
@@ -97,20 +97,24 @@ protected byte[] resolve0(Object returnValue,
             }
 
             HttpResponseSerializer serializer = null;
-            for (MediaType mediaType : mediaTypes) {
-                for (HttpResponseSerializer ser : serializers) {
-                    if (ser.supportsWrite(mediaType, returnValue.getClass())) {
-                        serializer = ser;
-                        break;
+            if (mediaTypes.isEmpty()) {
+                serializer = serializers.get(0);
+            } else {
+                for (MediaType mediaType : mediaTypes) {
+                    for (HttpResponseSerializer ser : serializers) {
+                        if (ser.supportsWrite(mediaType, returnValue.getClass())) {
+                            serializer = ser;
+                            break;
+                        }
                     }
                 }
+                if (serializer == null) {
+                    logger.warn("Failed to find serializer for media type '{}', try to use default serializer.",
+                            mediaTypes);
+                    serializer = serializers.get(0);
+                }
             }
 
-            if (serializer == null) {
-                logger.warn("Failed to find serializer for media type '{}', try to use default serializer.",
-                        mediaTypes);
-                serializer = serializers.get(0);
-            }
             final Object returnValueToWrite = serializer.customResponse(request, response, returnValue);
             return Serializers.serializeBySerializer(serializer, returnValueToWrite, response);
         }