bugfix: jackson serializing can compatible with empty beans (#70)

* bugfix: jackson serializing can compatible with empty beans

Author: mz126

trpc-core/src/main/java/com/tencent/trpc/core/utils/JsonUtils.java

@@ -16,6 +16,7 @@
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.JavaType;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
 import com.tencent.trpc.core.exception.ErrorCode;
 import com.tencent.trpc.core.exception.TRpcException;
 import com.tencent.trpc.core.logger.Logger;
@@ -39,6 +40,8 @@ public class JsonUtils {
         objectMapper.setSerializationInclusion(Include.NON_NULL);
         // Do not throw an error when deserializing if there are no corresponding properties
         objectMapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
+        // Do not throw an error when serializing if there are no public fields
+        objectMapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
     }
 
     /**

trpc-core/src/test/java/com/tencent/trpc/core/serialization/JsonSerializationTest.java

@@ -61,14 +61,6 @@ public void testJson2Pojo() {
      */
     @Test
     public void testJson2PojoEx() {
-        try {
-            JsonUtilsTest.TestObj1 obj1 = new JsonUtilsTest.TestObj1();
-            obj1.setTest(123);
-            serial.serialize(obj1);
-            Assert.fail();
-        } catch (Exception e) {
-            Assert.assertTrue(e.getMessage().contains("json serialize ex:"));
-        }
         try {
             byte[] bytes = serial.serialize(obj);
             GenericsObj deserialize = serial.deserialize(bytes, GenericsObj.class);

trpc-core/src/test/java/com/tencent/trpc/core/utils/JsonUtilsTest.java

@@ -32,6 +32,7 @@ public class JsonUtilsTest {
     private static final String JSON = "{\"test\":123}";
     private static final String JSON_LIST = "[{\"test\":123},{\"test\":123}]";
     private static final String ERROR_JSON = "{\"test\":123,A}";
+    private static final String EMPTY_JSON = "{}";
 
     @Test
     public void testCopy() {
@@ -134,7 +135,7 @@ public void testToJsonWithDefaultValue() {
         TestObj1 obj1 = new TestObj1();
         obj1.setTest(123);
         String aaa = JsonUtils.toJson(obj1, "aaa");
-        Assert.assertEquals("aaa", aaa);
+        Assert.assertEquals(EMPTY_JSON, aaa);
     }
 
     @Test