fix issue struct attribute converting when has no json name but with omitempty tag (#2486)

util/gconv/gconv_map.go

@@ -332,6 +332,9 @@ func doMapConvertForMapOrStructValue(in doMapConvertForMapOrStructValueInput) in
 						mapKey = strings.TrimSpace(array[0])
 					}
 				}
+				if mapKey == "" {
+					mapKey = fieldName
+				}
 			}
 			if in.RecursiveOption || rtField.Anonymous {
 				// Do map converting recursively.

util/gconv/gconv_z_unit_map_test.go

@@ -606,3 +606,17 @@ func TestMapsDeep(t *testing.T) {
 		t.Assert(list[1]["id"], 200)
 	})
 }
+
+func TestMapWithJsonOmitEmpty(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		type S struct {
+			Key   string      `json:",omitempty"`
+			Value interface{} `json:",omitempty"`
+		}
+		s := S{
+			Key:   "",
+			Value: 1,
+		}
+		t.Assert(gconv.Map(s), g.Map{"Value": 1})
+	})
+}