diff --git a/feature_reflect_extension.go b/feature_reflect_extension.go
index 3dd3829..74f4b8b 100644
--- a/feature_reflect_extension.go
+++ b/feature_reflect_extension.go
@@ -269,7 +269,7 @@ func describeStruct(cfg *frozenConfig, typ reflect.Type) (*StructDescriptor, err
 		if decoder == nil {
 			var err error
 			decoder, err = decoderOfType(cfg, field.Type)
-			if err != nil {
+			if len(fieldNames) > 0 && err != nil {
 				return nil, err
 			}
 		}
@@ -277,11 +277,11 @@ func describeStruct(cfg *frozenConfig, typ reflect.Type) (*StructDescriptor, err
 		if encoder == nil {
 			var err error
 			encoder, err = encoderOfType(cfg, field.Type)
-			if err != nil {
+			if len(fieldNames) > 0 && err != nil {
 				return nil, err
 			}
 			// map is stored as pointer in the struct
-			if field.Type.Kind() == reflect.Map {
+			if encoder != nil && field.Type.Kind() == reflect.Map {
 				encoder = &optionalEncoder{encoder}
 			}
 		}
diff --git a/jsoniter_customize_test.go b/jsoniter_customize_test.go
index b4bf529..628f89e 100644
--- a/jsoniter_customize_test.go
+++ b/jsoniter_customize_test.go
@@ -2,11 +2,12 @@ package jsoniter
 
 import (
 	"encoding/json"
-	"github.com/stretchr/testify/require"
 	"strconv"
 	"testing"
 	"time"
 	"unsafe"
+
+	"github.com/stretchr/testify/require"
 )
 
 func Test_customize_type_decoder(t *testing.T) {
@@ -82,7 +83,7 @@ func Test_customize_field_decoder(t *testing.T) {
 }
 
 type TestObject1 struct {
-	field1 string
+	Field1 string
 }
 
 type testExtension struct {
@@ -93,7 +94,7 @@ func (extension *testExtension) UpdateStructDescriptor(structDescriptor *StructD
 	if structDescriptor.Type.String() != "jsoniter.TestObject1" {
 		return
 	}
-	binding := structDescriptor.GetField("field1")
+	binding := structDescriptor.GetField("Field1")
 	binding.Encoder = &funcEncoder{fun: func(ptr unsafe.Pointer, stream *Stream) {
 		str := *((*string)(ptr))
 		val, _ := strconv.Atoi(str)
@@ -112,7 +113,7 @@ func Test_customize_field_by_extension(t *testing.T) {
 	obj := TestObject1{}
 	err := UnmarshalFromString(`{"field-1": 100}`, &obj)
 	should.Nil(err)
-	should.Equal("100", obj.field1)
+	should.Equal("100", obj.Field1)
 	str, err := MarshalToString(obj)
 	should.Nil(err)
 	should.Equal(`{"field-1":100}`, str)
diff --git a/jsoniter_struct_encoder_test.go b/jsoniter_struct_encoder_test.go
new file mode 100644
index 0000000..0e3e541
--- /dev/null
+++ b/jsoniter_struct_encoder_test.go
@@ -0,0 +1,52 @@
+package jsoniter
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_encode_unexported_field(t *testing.T) {
+	type TestData struct {
+		a int
+		b <-chan int
+		C int
+		d *time.Timer
+	}
+
+	should := require.New(t)
+
+	testChan := make(<-chan int, 10)
+	testTimer := time.NewTimer(10 * time.Second)
+
+	obj := &TestData{
+		a: 42,
+		b: testChan,
+		C: 21,
+		d: testTimer,
+	}
+
+	jb, err := json.Marshal(obj)
+	should.NoError(err)
+	should.Equal([]byte(`{"C":21}`), jb)
+
+	err = json.Unmarshal([]byte(`{"a": 444, "b":"bad", "C":55, "d":{"not": "a timer"}}`), obj)
+	should.NoError(err)
+	should.Equal(42, obj.a)
+	should.Equal(testChan, obj.b)
+	should.Equal(55, obj.C)
+	should.Equal(testTimer, obj.d)
+
+	jb, err = Marshal(obj)
+	should.NoError(err)
+	should.Equal(jb, []byte(`{"C":55}`))
+
+	err = Unmarshal([]byte(`{"a": 444, "b":"bad", "C":256, "d":{"not":"a timer"}}`), obj)
+	should.NoError(err)
+	should.Equal(42, obj.a)
+	should.Equal(testChan, obj.b)
+	should.Equal(256, obj.C)
+	should.Equal(testTimer, obj.d)
+}