diff --git a/pkgs/mq/message.go b/pkgs/mq/message.go
index 8177982..36a7ad3 100644
--- a/pkgs/mq/message.go
+++ b/pkgs/mq/message.go
@@ -1,16 +1,9 @@
 package mq
 
 import (
-	"bytes"
-	"fmt"
-	"reflect"
-	"strings"
-	"unsafe"
-
-	jsoniter "github.com/json-iterator/go"
-	"github.com/modern-go/reflect2"
 	"gitlink.org.cn/cloudream/common/pkgs/types"
 	myreflect "gitlink.org.cn/cloudream/common/utils/reflect"
+	"gitlink.org.cn/cloudream/common/utils/serder"
 )
 
 const (
@@ -86,298 +79,20 @@ func MakeHeartbeatMessage() Message {
 	return msg
 }
 
-type TypeUnionWithTypeName struct {
-	Union          types.TypeUnion
-	TypeNameToType map[string]myreflect.Type
-}
-
-func (u *TypeUnionWithTypeName) Register(typ myreflect.Type) {
-	u.Union.ElementTypes = append(msgBodyTypeUnion.Union.ElementTypes, typ)
-	u.TypeNameToType[makeFullTypeName(typ)] = typ
-}
-
-var msgBodyTypeUnion *TypeUnionWithTypeName
+var msgBodyTypeUnion = serder.UseTypeUnionExternallyTagged(types.Ref(types.NewTypeUnion[MessageBody]()))
 
 // 所有新定义的Message都需要在init中调用此函数
 func RegisterMessage[T MessageBody]() {
-	msgBodyTypeUnion.Register(myreflect.TypeOf[T]())
-}
-
-// 在序列化结构体中包含的UnionType类型字段时，会将字段值的实际类型保存在序列化后的结果中。
-// 在反序列化时，会根据类型信息重建原本的字段值。
-// 注：TypeUnion.UnionType必须是一个interface
-func RegisterUnionType(union types.TypeUnion) *TypeUnionWithTypeName {
-	myUnion := &TypeUnionWithTypeName{
-		Union:          union,
-		TypeNameToType: make(map[string]reflect.Type),
-	}
-
-	for _, typ := range union.ElementTypes {
-		myUnion.TypeNameToType[makeFullTypeName(typ)] = typ
-	}
-
-	if union.UnionType.NumMethod() == 0 {
-		registerForEFace(myUnion)
-	} else {
-		registerForIFace(myUnion)
-	}
-
-	return myUnion
-}
-
-// 无方法的interface类型
-func registerForEFace(myUnion *TypeUnionWithTypeName) {
-	jsoniter.RegisterTypeEncoderFunc(myUnion.Union.UnionType.String(),
-		func(ptr unsafe.Pointer, stream *jsoniter.Stream) {
-			// 无方法的interface底层数据结构都是eface类型，所以可以直接转*any
-			val := *(*any)(ptr)
-			if val != nil {
-				stream.WriteArrayStart()
-
-				valType := myreflect.TypeOfValue(val)
-				if !myUnion.Union.Include(valType) {
-					stream.Error = fmt.Errorf("type %v is not in union %v", valType, myUnion.Union.UnionType)
-					return
-				}
-
-				stream.WriteString(makeFullTypeName(valType))
-				stream.WriteRaw(",")
-				stream.WriteVal(val)
-				stream.WriteArrayEnd()
-			} else {
-				stream.WriteNil()
-			}
-		},
-		func(p unsafe.Pointer) bool {
-			return false
-		})
-
-	jsoniter.RegisterTypeDecoderFunc(myUnion.Union.UnionType.String(),
-		func(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
-			// 无方法的interface底层都是eface结构体，所以可以直接转*any
-			vp := (*any)(ptr)
-
-			nextTkType := iter.WhatIsNext()
-			if nextTkType == jsoniter.NilValue {
-				iter.ReadNil()
-				*vp = nil
-
-			} else if nextTkType == jsoniter.ArrayValue {
-				iter.ReadArray()
-				typeStr := iter.ReadString()
-				iter.ReadArray()
-
-				typ, ok := myUnion.TypeNameToType[typeStr]
-				if !ok {
-					iter.ReportError("decode UnionType", fmt.Sprintf("unknow type string %s under %v", typeStr, myUnion.Union.UnionType))
-					return
-				}
-
-				// 如果目标类型已经是个指针类型*T，那么在New的时候就需要使用T，
-				// 否则New出来的是会是**T，这将导致后续的反序列化出问题
-				if typ.Kind() == reflect.Pointer {
-					val := reflect.New(typ.Elem())
-					iter.ReadVal(val.Interface())
-					*vp = val.Interface()
-
-				} else {
-					val := reflect.New(typ)
-					iter.ReadVal(val.Interface())
-					*vp = val.Elem().Interface()
-				}
-
-				iter.ReadArray()
-			} else {
-				iter.ReportError("decode UnionType", fmt.Sprintf("unknow next token type %v", nextTkType))
-				return
-			}
-		})
-}
-
-// 有方法的interface类型
-func registerForIFace(myUnion *TypeUnionWithTypeName) {
-	jsoniter.RegisterTypeEncoderFunc(myUnion.Union.UnionType.String(),
-		func(ptr unsafe.Pointer, stream *jsoniter.Stream) {
-			// 有方法的interface底层都是iface结构体，可以将其转成eface，转换后不损失类型信息
-			val := reflect2.IFaceToEFace(ptr)
-			if val != nil {
-				stream.WriteArrayStart()
-
-				valType := myreflect.TypeOfValue(val)
-				if !myUnion.Union.Include(valType) {
-					stream.Error = fmt.Errorf("type %v is not in union %v", valType, myUnion.Union.UnionType)
-					return
-				}
-
-				stream.WriteString(makeFullTypeName(valType))
-				stream.WriteRaw(",")
-				stream.WriteVal(val)
-				stream.WriteArrayEnd()
-			} else {
-				stream.WriteNil()
-			}
-		},
-		func(p unsafe.Pointer) bool {
-			return false
-		})
-
-	jsoniter.RegisterTypeDecoderFunc(myUnion.Union.UnionType.String(),
-		func(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
-
-			nextTkType := iter.WhatIsNext()
-			if nextTkType == jsoniter.NilValue {
-				iter.ReadNil()
-
-			} else if nextTkType == jsoniter.ArrayValue {
-				iter.ReadArray()
-				typeStr := iter.ReadString()
-				iter.ReadArray()
-
-				typ, ok := myUnion.TypeNameToType[typeStr]
-				if !ok {
-					iter.ReportError("decode UnionType", fmt.Sprintf("unknow type string %s under %v", typeStr, myUnion.Union.UnionType))
-					return
-				}
-
-				// 如果目标类型已经是个指针类型*T，那么在New的时候就需要使用T，
-				// 否则New出来的是会是**T，这将导致后续的反序列化出问题
-				if typ.Kind() == reflect.Pointer {
-					val := reflect.New(typ.Elem())
-					iter.ReadVal(val.Interface())
-
-					retVal := reflect.NewAt(myUnion.Union.UnionType, ptr)
-					retVal.Elem().Set(val)
-
-				} else {
-					val := reflect.New(typ)
-					iter.ReadVal(val.Interface())
-
-					retVal := reflect.NewAt(myUnion.Union.UnionType, ptr)
-					retVal.Elem().Set(val.Elem())
-				}
-
-				iter.ReadArray()
-			} else {
-				iter.ReportError("decode UnionType", fmt.Sprintf("unknow next token type %v", nextTkType))
-				return
-			}
-		})
-}
-
-func makeFullTypeName(typ myreflect.Type) string {
-	refs := 0
-
-	realType := typ
-	for realType.Kind() == reflect.Pointer {
-		refs++
-		realType = realType.Elem()
-	}
-
-	return fmt.Sprintf("%s%s.%s", strings.Repeat("*", refs), realType.PkgPath(), realType.Name())
-}
-
-/*
-// 如果对一个类型T调用了此函数，那么在序列化结构体中包含的T类型字段时，
-// 会将字段值的实际类型保存在序列化后的结果中
-// 在反序列化时，会根据类型信息重建原本的字段值。
-//
-// 只会处理types指定的类型。
-func RegisterTypeSet[T any](types ...myreflect.Type) *serder.UnionTypeInfo {
-	eleTypes := serder.NewTypeNameResolver(true)
-	set := serder.UnionTypeInfo{
-		UnionType:    myreflect.TypeOf[T](),
-		ElementTypes: eleTypes,
-	}
-
-	for _, t := range types {
-		eleTypes.Register(t)
+	err := msgBodyTypeUnion.Add(myreflect.TypeOf[T]())
+	if err != nil {
+		panic(err)
 	}
-
-		TODO 暂时保留这一段代码，如果RegisterUnionType中的非泛型版本出了问题，则重新使用这一部分的代码
-			unionTypes[set.UnionType] = set
-
-			jsoniter.RegisterTypeEncoderFunc(myreflect.TypeOf[T]().String(),
-				func(ptr unsafe.Pointer, stream *jsoniter.Stream) {
-					val := *((*T)(ptr))
-					var ifVal any = val
-
-					if ifVal != nil {
-						stream.WriteArrayStart()
-						typeStr, err := set.ElementTypes.TypeToString(myreflect.TypeOfValue(val))
-						if err != nil {
-							stream.Error = err
-							return
-						}
-						stream.WriteString(typeStr)
-						stream.WriteRaw(",")
-						stream.WriteVal(val)
-						stream.WriteArrayEnd()
-					} else {
-						stream.WriteNil()
-					}
-				},
-				func(p unsafe.Pointer) bool {
-					return false
-				})
-
-			jsoniter.RegisterTypeDecoderFunc(myreflect.TypeOf[T]().String(),
-				func(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
-					vp := (*T)(ptr)
-
-					nextTkType := iter.WhatIsNext()
-					if nextTkType == jsoniter.NilValue {
-						iter.ReadNil()
-						var zero T
-						*vp = zero
-					} else if nextTkType == jsoniter.ArrayValue {
-						iter.ReadArray()
-						typeStr := iter.ReadString()
-						iter.ReadArray()
-
-						typ, err := set.ElementTypes.StringToType(typeStr)
-						if err != nil {
-							iter.ReportError("get type from string", err.Error())
-							return
-						}
-
-						val := reflect.New(typ)
-						iter.ReadVal(val.Interface())
-						*vp = val.Elem().Interface().(T)
-
-						iter.ReadArray()
-					} else {
-						iter.ReportError("parse TypeSet field", fmt.Sprintf("unknow next token type %v", nextTkType))
-						return
-					}
-				})
-	RegisterUnionType(serder.NewTypeUnion[T]("", serder.NewTypeNameResolver(true)))
-	return &set
 }
-*/
 
 func Serialize(msg Message) ([]byte, error) {
-	buf := bytes.NewBuffer(nil)
-	enc := jsoniter.NewEncoder(buf)
-	err := enc.Encode(msg)
-	if err != nil {
-		return nil, err
-	}
-
-	return buf.Bytes(), nil
+	return serder.ObjectToJSONEx(msg)
 }
 
 func Deserialize(data []byte) (*Message, error) {
-	dec := jsoniter.NewDecoder(bytes.NewBuffer(data))
-
-	var msg Message
-	err := dec.Decode(&msg)
-	if err != nil {
-		return nil, err
-	}
-
-	return &msg, nil
-}
-
-func init() {
-	msgBodyTypeUnion = RegisterUnionType(types.NewTypeUnion[MessageBody]())
+	return serder.JSONToObjectEx[*Message](data)
 }
diff --git a/pkgs/mq/message_test.go b/pkgs/mq/message_test.go
index 631d9c5..b2482fa 100644
--- a/pkgs/mq/message_test.go
+++ b/pkgs/mq/message_test.go
@@ -3,7 +3,6 @@ package mq
 import (
 	"bytes"
 	"fmt"
-	"reflect"
 	"testing"
 	"unsafe"
 
@@ -11,6 +10,7 @@ import (
 	. "github.com/smartystreets/goconvey/convey"
 	"gitlink.org.cn/cloudream/common/pkgs/types"
 	myreflect "gitlink.org.cn/cloudream/common/utils/reflect"
+	"gitlink.org.cn/cloudream/common/utils/serder"
 )
 
 func TestMessage(t *testing.T) {
@@ -146,7 +146,7 @@ func TestMessage(t *testing.T) {
 			Value MyTypeUnion
 		}
 		RegisterMessage[*Body]()
-		RegisterUnionType(types.NewTypeUnion[MyTypeUnion]((*EleType1)(nil)))
+		serder.UseTypeUnionExternallyTagged(types.Ref(types.NewTypeUnion[MyTypeUnion]((*EleType1)(nil))))
 
 		msg := MakeAppDataMessage(&Body{Value: &EleType1{
 			Value: 1,
@@ -174,7 +174,7 @@ func TestMessage(t *testing.T) {
 			Value MyTypeUnion
 		}
 		RegisterMessage[*Body]()
-		RegisterUnionType(types.NewTypeUnion[MyTypeUnion]((*EleType1)(nil)))
+		serder.UseTypeUnionExternallyTagged(types.Ref(types.NewTypeUnion[MyTypeUnion]((*EleType1)(nil))))
 
 		msg := MakeAppDataMessage(&Body{Value: &EleType1{
 			Value: 1,
@@ -200,7 +200,7 @@ func TestMessage(t *testing.T) {
 			Value MyTypeUnion
 		}
 		RegisterMessage[*Body]()
-		RegisterUnionType(types.NewTypeUnion[MyTypeUnion]())
+		serder.UseTypeUnionExternallyTagged(types.Ref(types.NewTypeUnion[MyTypeUnion]()))
 
 		msg := MakeAppDataMessage(&Body{Value: nil})
 		data, err := Serialize(msg)
@@ -220,26 +220,10 @@ func TestMessage(t *testing.T) {
 			Value MyTypeUnion
 		}
 		RegisterMessage[*Body]()
-		RegisterUnionType(types.NewTypeUnion[MyTypeUnion]())
+		serder.UseTypeUnionExternallyTagged(types.Ref(types.NewTypeUnion[MyTypeUnion]()))
 
 		msg := MakeAppDataMessage(&Body{Value: &struct{}{}})
 		_, err := Serialize(msg)
 		So(err, ShouldNotBeNil)
 	})
-
-}
-
-func TestMakeFullTypeName(t *testing.T) {
-	Convey("指针类型", t, func() {
-		type St struct{}
-
-		typeName := makeFullTypeName(myreflect.TypeOf[St]())
-		So(typeName, ShouldEqual, "gitlink.org.cn/cloudream/common/pkgs/mq.St")
-
-		typeName = makeFullTypeName(reflect.PointerTo(myreflect.TypeOf[St]()))
-		So(typeName, ShouldEqual, "*gitlink.org.cn/cloudream/common/pkgs/mq.St")
-
-		typeName = makeFullTypeName(reflect.PointerTo(reflect.PointerTo(myreflect.TypeOf[St]())))
-		So(typeName, ShouldEqual, "**gitlink.org.cn/cloudream/common/pkgs/mq.St")
-	})
 }
diff --git a/pkgs/types/types.go b/pkgs/types/types.go
new file mode 100644
index 0000000..d86e228
--- /dev/null
+++ b/pkgs/types/types.go
@@ -0,0 +1,5 @@
+package types
+
+func Ref[T any](val T) *T {
+	return &val
+}
diff --git a/pkgs/types/union.go b/pkgs/types/union.go
index 10eeffd..ec4ecce 100644
--- a/pkgs/types/union.go
+++ b/pkgs/types/union.go
@@ -1,6 +1,7 @@
 package types
 
 import (
+	"fmt"
 	"reflect"
 
 	myreflect "gitlink.org.cn/cloudream/common/utils/reflect"
@@ -37,6 +38,11 @@ func (u *TypeUnion) Include(typ myreflect.Type) bool {
 	return false
 }
 
-func (u *TypeUnion) Add(typ myreflect.Type) {
+func (u *TypeUnion) Add(typ myreflect.Type) error {
+	if !typ.AssignableTo(u.UnionType) {
+		return fmt.Errorf("type is not assignable to union type")
+	}
+
 	u.ElementTypes = append(u.ElementTypes, typ)
+	return nil
 }
diff --git a/sdks/scheduler/models.go b/sdks/scheduler/models.go
index 65259ba..29a2594 100644
--- a/sdks/scheduler/models.go
+++ b/sdks/scheduler/models.go
@@ -1,7 +1,6 @@
 package schsdk
 
 import (
-	"gitlink.org.cn/cloudream/common/pkgs/mq"
 	"gitlink.org.cn/cloudream/common/pkgs/types"
 	cdssdk "gitlink.org.cn/cloudream/common/sdks/storage"
 	"gitlink.org.cn/cloudream/common/utils/serder"
@@ -38,8 +37,7 @@ var JobInfoTypeUnion = types.NewTypeUnion[JobInfo](
 	(*NormalJobInfo)(nil),
 	(*ResourceJobInfo)(nil),
 )
-var _ = serder.RegisterNewTaggedTypeUnion(JobInfoTypeUnion, "Type", "type")
-var _ = mq.RegisterUnionType(JobInfoTypeUnion)
+var _ = serder.UseTypeUnionInternallyTagged(&JobInfoTypeUnion, "type")
 
 type JobInfoBase struct {
 	LocalJobID string `json:"localJobID"`
@@ -50,16 +48,18 @@ func (i *JobInfoBase) GetLocalJobID() string {
 }
 
 type NormalJobInfo struct {
+	serder.Metadata `union:"Normal"`
 	JobInfoBase
-	Type      string           `json:"type" union:"Normal"`
+	Type      string           `json:"type"`
 	Files     JobFilesInfo     `json:"files"`
 	Runtime   JobRuntimeInfo   `json:"runtime"`
 	Resources JobResourcesInfo `json:"resources"`
 }
 
 type ResourceJobInfo struct {
+	serder.Metadata `union:"Resource"`
 	JobInfoBase
-	Type             string                     `json:"type" union:"Resource"`
+	Type             string                     `json:"type"`
 	BucketID         int64                      `json:"bucketID"`
 	Redundancy       cdssdk.TypedRedundancyInfo `json:"redundancy"`
 	TargetLocalJobID string                     `json:"targetLocalJobID"`
@@ -81,34 +81,37 @@ var FileInfoTypeUnion = types.NewTypeUnion[JobFileInfo](
 	(*ResourceJobFileInfo)(nil),
 	(*ImageJobFileInfo)(nil),
 )
-var _ = serder.RegisterNewTaggedTypeUnion(FileInfoTypeUnion, "Type", "type")
-var _ = mq.RegisterUnionType(FileInfoTypeUnion)
+var _ = serder.UseTypeUnionInternallyTagged(&FileInfoTypeUnion, "type")
 
 type JobFileInfoBase struct{}
 
 func (i *JobFileInfoBase) Noop() {}
 
 type PackageJobFileInfo struct {
+	serder.Metadata `union:"Package"`
 	JobFileInfoBase
-	Type      string `json:"type" union:"Package"`
+	Type      string `json:"type"`
 	PackageID int64  `json:"packageID"`
 }
 
 type LocalJobFileInfo struct {
+	serder.Metadata `union:"LocalFile"`
 	JobFileInfoBase
-	Type      string `json:"type" union:"LocalFile"`
+	Type      string `json:"type"`
 	LocalPath string `json:"localPath"`
 }
 
 type ResourceJobFileInfo struct {
+	serder.Metadata `union:"Resource"`
 	JobFileInfoBase
-	Type               string `json:"type" union:"Resource"`
+	Type               string `json:"type"`
 	ResourceLocalJobID string `json:"resourceLocalJobID"`
 }
 
 type ImageJobFileInfo struct {
+	serder.Metadata `union:"Image"`
 	JobFileInfoBase
-	Type    string  `json:"type" union:"Image"`
+	Type    string  `json:"type"`
 	ImageID ImageID `json:"imageID"`
 }
 
@@ -133,21 +136,6 @@ type JobResourcesInfo struct {
 	Memory  int64   `json:"memory"`
 }
 
-func JobSetInfoFromJSON(data []byte) (*JobSetInfo, error) {
-	mp := make(map[string]any)
-	if err := serder.JSONToObject(data, &mp); err != nil {
-		return nil, err
-	}
-
-	var ret JobSetInfo
-	err := serder.MapToObject(mp, &ret)
-	if err != nil {
-		return nil, err
-	}
-
-	return &ret, nil
-}
-
 type JobSetFilesUploadScheme struct {
 	LocalFileSchemes []LocalFileUploadScheme `json:"localFileUploadSchemes"`
 }
diff --git a/sdks/unifyops/models.go b/sdks/unifyops/models.go
index 655738c..6fe3d7b 100644
--- a/sdks/unifyops/models.go
+++ b/sdks/unifyops/models.go
@@ -1,7 +1,6 @@
 package uopsdk
 
 import (
-	"gitlink.org.cn/cloudream/common/pkgs/mq"
 	"gitlink.org.cn/cloudream/common/pkgs/types"
 	"gitlink.org.cn/cloudream/common/utils/serder"
 )
@@ -37,8 +36,7 @@ var ResourceDataTypeUnion = types.NewTypeUnion[ResourceData](
 	(*StorageResourceData)(nil),
 	(*MemoryResourceData)(nil),
 )
-var _ = serder.RegisterNewTaggedTypeUnion(ResourceDataTypeUnion, "Name", "name")
-var _ = mq.RegisterUnionType(ResourceDataTypeUnion)
+var _ = serder.UseTypeUnionInternallyTagged(&ResourceDataTypeUnion, "name")
 
 type ResourceDataBase struct{}
 
@@ -50,8 +48,9 @@ type UnitValue[T any] struct {
 }
 
 type CPUResourceData struct {
+	serder.Metadata `union:"CPU"`
 	ResourceDataBase
-	Name      ResourceType     `json:"name" union:"CPU"`
+	Name      ResourceType     `json:"name"`
 	Total     UnitValue[int64] `json:"total"`
 	Available UnitValue[int64] `json:"available"`
 }
@@ -65,8 +64,9 @@ func NewCPUResourceData(total UnitValue[int64], available UnitValue[int64]) *CPU
 }
 
 type NPUResourceData struct {
+	serder.Metadata `union:"NPU"`
 	ResourceDataBase
-	Name      ResourceType     `json:"name" union:"NPU"`
+	Name      ResourceType     `json:"name"`
 	Total     UnitValue[int64] `json:"total"`
 	Available UnitValue[int64] `json:"available"`
 }
@@ -80,8 +80,9 @@ func NewNPUResourceData(total UnitValue[int64], available UnitValue[int64]) *NPU
 }
 
 type GPUResourceData struct {
+	serder.Metadata `union:"GPU"`
 	ResourceDataBase
-	Name      ResourceType     `json:"name" union:"GPU"`
+	Name      ResourceType     `json:"name"`
 	Total     UnitValue[int64] `json:"total"`
 	Available UnitValue[int64] `json:"available"`
 }
@@ -95,8 +96,9 @@ func NewGPUResourceData(total UnitValue[int64], available UnitValue[int64]) *GPU
 }
 
 type MLUResourceData struct {
+	serder.Metadata `union:"MLU"`
 	ResourceDataBase
-	Name      ResourceType     `json:"name" union:"MLU"`
+	Name      ResourceType     `json:"name"`
 	Total     UnitValue[int64] `json:"total"`
 	Available UnitValue[int64] `json:"available"`
 }
@@ -110,8 +112,9 @@ func NewMLUResourceData(total UnitValue[int64], available UnitValue[int64]) *MLU
 }
 
 type StorageResourceData struct {
+	serder.Metadata `union:"STORAGE"`
 	ResourceDataBase
-	Name      ResourceType       `json:"name" union:"STORAGE"`
+	Name      ResourceType       `json:"name"`
 	Total     UnitValue[float64] `json:"total"`
 	Available UnitValue[float64] `json:"available"`
 }
@@ -125,8 +128,9 @@ func NewStorageResourceData(total UnitValue[float64], available UnitValue[float6
 }
 
 type MemoryResourceData struct {
+	serder.Metadata `union:"MEMORY"`
 	ResourceDataBase
-	Name      ResourceType       `json:"name" union:"MEMORY"`
+	Name      ResourceType       `json:"name"`
 	Total     UnitValue[float64] `json:"total"`
 	Available UnitValue[float64] `json:"available"`
 }
diff --git a/utils/serder/serder.go b/utils/serder/serder.go
index 1d46d0e..81b36b5 100644
--- a/utils/serder/serder.go
+++ b/utils/serder/serder.go
@@ -1,19 +1,64 @@
 package serder
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io"
 	"reflect"
 	"strings"
 
-	"gitlink.org.cn/cloudream/common/pkgs/types"
+	jsoniter "github.com/json-iterator/go"
 )
 
+var unionHandler = UnionHandler{
+	internallyTagged: make(map[reflect.Type]*TypeUnionInternallyTagged),
+	externallyTagged: make(map[reflect.Type]*TypeUnionExternallyTagged),
+}
+
+var defaultAPI = func() jsoniter.API {
+	api := jsoniter.Config{
+		EscapeHTML: true,
+	}.Froze()
+
+	api.RegisterExtension(&unionHandler)
+	return api
+}()
+
+// 将对象转为JSON字符串。支持TypeUnion。
+func ObjectToJSONEx[T any](obj T) ([]byte, error) {
+	buf := new(bytes.Buffer)
+	enc := defaultAPI.NewEncoder(buf)
+	// 这里使用&obj而直接不使用obj的原因是，Encode的形参类型为any，
+	// 如果T是一个interface类型，将obj传递进去后，内部拿到的类型将会是obj的实际类型，
+	// 使用&obj，那么内部拿到的将会是*T类型，通过一层一层解引用查找Encoder时，能找到T对应的TypeUnion
+	err := enc.Encode(&obj)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+// 将JSON字符串转为对象。支持TypeUnion。
+func JSONToObjectEx[T any](data []byte) (T, error) {
+	var ret T
+	dec := defaultAPI.NewDecoder(bytes.NewReader(data))
+	err := dec.Decode(&ret)
+	if err != nil {
+		return ret, err
+	}
+
+	return ret, nil
+}
+
+// 将对象转为JSON字符串。如果需要支持解析TypeUnion类型，则使用"Ex"结尾的同名函数。
 func ObjectToJSON(obj any) ([]byte, error) {
 	return json.Marshal(obj)
 }
 
+// 将对象转为JSON字符串。如果需要支持解析TypeUnion类型，则使用"Ex"结尾的同名函数。
 func ObjectToJSONStream(obj any) io.ReadCloser {
 	pr, pw := io.Pipe()
 	enc := json.NewEncoder(pw)
@@ -30,10 +75,12 @@ func ObjectToJSONStream(obj any) io.ReadCloser {
 	return pr
 }
 
+// 将JSON字符串转为对象。如果需要支持解析TypeUnion类型，则使用"Ex"结尾的同名函数。
 func JSONToObject(data []byte, obj any) error {
 	return json.Unmarshal(data, obj)
 }
 
+// 将JSON字符串转为对象。如果需要支持解析TypeUnion类型，则使用"Ex"结尾的同名函数。
 func JSONToObjectStream(str io.Reader, obj any) error {
 	dec := json.NewDecoder(str)
 	err := dec.Decode(obj)
@@ -49,86 +96,21 @@ type TypeResolver interface {
 	StringToType(typeStr string) (reflect.Type, error)
 }
 
-var registeredTaggedTypeUnions []*TaggedUnionType
-
-type TaggedUnionType struct {
-	Union          types.TypeUnion
-	StrcutTagField string
-	JSONTagField   string
-	TagToType      map[string]reflect.Type
-}
-
-// 根据指定的字段的值来区分不同的类型。值可以通过在字段增加“union”Tag来指定。如果没有指定，则使用类型名。
-func NewTaggedTypeUnion(union types.TypeUnion, structTagField string, jsonTagField string) *TaggedUnionType {
-	tagToType := make(map[string]reflect.Type)
-
-	for _, typ := range union.ElementTypes {
-		if structTagField == "" {
-			tagToType[typ.Name()] = typ
-			continue
-		}
-
-		// 如果ElementType是一个指向结构体的指针，那么就遍历结构体的字段（解引用）
-		structType := typ
-		for structType.Kind() == reflect.Pointer {
-			structType = structType.Elem()
-		}
-
-		field, ok := structType.FieldByName(structTagField)
-		if !ok {
-			tagToType[typ.Name()] = typ
-			continue
-		}
-
-		tag := field.Tag.Get("union")
-		if tag == "" {
-			tagToType[typ.Name()] = typ
-			continue
-		}
-
-		tagToType[tag] = typ
-	}
-
-	return &TaggedUnionType{
-		Union:          union,
-		StrcutTagField: structTagField,
-		JSONTagField:   jsonTagField,
-		TagToType:      tagToType,
-	}
-}
-
-// 注册一个TaggedTypeUnion
-func RegisterTaggedTypeUnion(union *TaggedUnionType) *TaggedUnionType {
-	registeredTaggedTypeUnions = append(registeredTaggedTypeUnions, union)
-	return union
-}
-
-// 创建并注册一个TaggedTypeUnion
-func RegisterNewTaggedTypeUnion(union types.TypeUnion, structTagField string, jsonTagField string) *TaggedUnionType {
-	taggedUnion := NewTaggedTypeUnion(union, structTagField, jsonTagField)
-	RegisterTaggedTypeUnion(taggedUnion)
-	return taggedUnion
-}
-
 type MapToObjectOption struct {
-	UnionTypes             []*TaggedUnionType // 转换过程中遇到这些类型时，会依据指定的字段的值，来决定转换后的实际类型
-	NoRegisteredUnionTypes bool               // 是否不使用全局注册的UnionType
+	NoRegisteredUnionTypes bool // 是否不使用全局注册的UnionType
 }
 
+// TODO 使用这个函数来处理TypeUnion的地方都可以直接使用Ex系列的函数
 func MapToObject(m map[string]any, obj any, opt ...MapToObjectOption) error {
 	var op MapToObjectOption
 	if len(opt) > 0 {
 		op = opt[0]
 	}
 
-	unionTypeMapping := make(map[reflect.Type]*TaggedUnionType)
-
-	for _, u := range op.UnionTypes {
-		unionTypeMapping[u.Union.UnionType] = u
-	}
+	unionTypeMapping := make(map[reflect.Type]*TypeUnionInternallyTagged)
 
 	if !op.NoRegisteredUnionTypes {
-		for _, u := range registeredTaggedTypeUnions {
+		for _, u := range unionHandler.internallyTagged {
 			unionTypeMapping[u.Union.UnionType] = u
 		}
 	}
@@ -142,14 +124,14 @@ func MapToObject(m map[string]any, obj any, opt ...MapToObjectOption) error {
 			}
 
 			mp := from.Interface().(map[string]any)
-			tag, ok := mp[info.JSONTagField]
+			tag, ok := mp[info.TagField]
 			if !ok {
-				return nil, fmt.Errorf("converting to %v: no tag field %s in map", toType, info.JSONTagField)
+				return nil, fmt.Errorf("converting to %v: no tag field %s in map", toType, info.TagField)
 			}
 
 			tagStr, ok := tag.(string)
 			if !ok {
-				return nil, fmt.Errorf("converting to %v: tag field %s value is %v, which is not a string", toType, info.JSONTagField, tag)
+				return nil, fmt.Errorf("converting to %v: tag field %s value is %v, which is not a string", toType, info.TagField, tag)
 			}
 
 			eleType, ok := info.TagToType[tagStr]
diff --git a/utils/serder/serder_test.go b/utils/serder/serder_test.go
index ba3bf6d..e2c4b8c 100644
--- a/utils/serder/serder_test.go
+++ b/utils/serder/serder_test.go
@@ -363,13 +363,15 @@ func Test_MapToObject(t *testing.T) {
 		type UnionType interface{}
 
 		type EleType1 struct {
-			Type   EleType `json:"type" union:"1"`
-			Value1 string  `json:"value1"`
+			Metadata `union:"1"`
+			Type     EleType `json:"type"`
+			Value1   string  `json:"value1"`
 		}
 
 		type EleType2 struct {
-			Type   EleType `json:"type" union:"2"`
-			Value2 int     `json:"value2"`
+			Metadata `union:"2"`
+			Type     EleType `json:"type"`
+			Value2   int     `json:"value2"`
 		}
 
 		type St struct {
@@ -390,17 +392,12 @@ func Test_MapToObject(t *testing.T) {
 		}
 
 		var ret St
-		err := MapToObject(mp, &ret, MapToObjectOption{
-			UnionTypes: []*TaggedUnionType{
-				NewTaggedTypeUnion(types.NewTypeUnion[UnionType](
-					(*EleType1)(nil),
-					(*EleType2)(nil),
-				),
-					"Type",
-					"type",
-				),
-			},
-		})
+		union := types.NewTypeUnion[UnionType](
+			(*EleType1)(nil),
+			(*EleType2)(nil),
+		)
+		UseTypeUnionInternallyTagged(&union, "type")
+		err := MapToObject(mp, &ret)
 
 		So(err, ShouldBeNil)
 
@@ -414,13 +411,15 @@ func Test_MapToObject(t *testing.T) {
 		type UnionType interface{}
 
 		type EleType1 struct {
-			Type   string `json:"type" union:"1"`
-			Value1 string `json:"value1"`
+			Metadata `union:"1"`
+			Type     string `json:"type"`
+			Value1   string `json:"value1"`
 		}
 
 		type EleType2 struct {
-			Type   string `json:"type" union:"2"`
-			Value2 int    `json:"value2"`
+			Metadata `union:"2"`
+			Type     string `json:"type"`
+			Value2   int    `json:"value2"`
 		}
 
 		mp := map[string]any{
@@ -429,17 +428,12 @@ func Test_MapToObject(t *testing.T) {
 		}
 
 		var ret UnionType
-		err := MapToObject(mp, &ret, MapToObjectOption{
-			UnionTypes: []*TaggedUnionType{
-				NewTaggedTypeUnion(types.NewTypeUnion[UnionType](
-					(*EleType1)(nil),
-					(*EleType2)(nil),
-				),
-					"Type",
-					"type",
-				),
-			},
-		})
+		union := types.NewTypeUnion[UnionType](
+			(*EleType1)(nil),
+			(*EleType2)(nil),
+		)
+		UseTypeUnionInternallyTagged(&union, "type")
+		err := MapToObject(mp, &ret)
 
 		So(err, ShouldBeNil)
 
@@ -464,7 +458,27 @@ func Test_MapToObject(t *testing.T) {
 		So(string(ret.Str), ShouldEqual, "1")
 	})
 }
-func Test_JSON(t *testing.T) {
+
+type Base interface {
+	Noop()
+}
+type St1 struct {
+	Metadata `union:"St1"`
+	Type     string
+	Val      string
+}
+
+func (*St1) Noop() {}
+
+type St2 struct {
+	Metadata `union:"St2"`
+	Type     string
+	Val      int
+}
+
+func (St2) Noop() {}
+
+func Test_ObjectToJSON2(t *testing.T) {
 	Convey("NewType", t, func() {
 		type Str string
 
@@ -484,4 +498,154 @@ func Test_JSON(t *testing.T) {
 		So(err, ShouldBeNil)
 		So(string(ret.Str), ShouldEqual, "1")
 	})
+
+	Convey("UnionType ExternallyTagged", t, func() {
+		type Base interface{}
+		type St1 struct {
+			Val string
+		}
+		type St2 struct {
+			Val int64
+		}
+		type Outter struct {
+			B []Base
+		}
+
+		union := types.NewTypeUnion[Base](St1{}, &St2{})
+		UseTypeUnionExternallyTagged(&union)
+
+		val := Outter{B: []Base{St1{Val: "asd"}, &St2{Val: 123}}}
+		data, err := ObjectToJSONEx(val)
+		So(err, ShouldBeNil)
+
+		ret, err := JSONToObjectEx[Outter](data)
+		So(err, ShouldBeNil)
+		So(ret, ShouldResemble, val)
+	})
+
+	Convey("UnionType InternallyTagged", t, func() {
+		type Base interface{}
+		type St1 struct {
+			Metadata `union:"St1"`
+			Type     string
+			Val      string
+		}
+		type St2 struct {
+			Metadata `union:"St2"`
+			Type     string
+			Val      int64
+		}
+		type Outter struct {
+			B []Base
+		}
+
+		union := types.NewTypeUnion[Base](St1{}, &St2{})
+		UseTypeUnionInternallyTagged(&union, "Type")
+
+		val := Outter{B: []Base{St1{Val: "asd", Type: "St1"}, &St2{Val: 123, Type: "St2"}}}
+		data, err := ObjectToJSONEx(val)
+		So(err, ShouldBeNil)
+
+		ret, err := JSONToObjectEx[Outter](data)
+		So(err, ShouldBeNil)
+		So(ret, ShouldResemble, val)
+	})
+
+	Convey("实参类型和目标类型本身就是UnionType ExternallyTagged", t, func() {
+		type Base interface{}
+		type St1 struct {
+			Val string
+		}
+		union := types.NewTypeUnion[Base](St1{})
+		UseTypeUnionExternallyTagged(&union)
+
+		var val Base = St1{Val: "asd"}
+		data, err := ObjectToJSONEx(val)
+		So(err, ShouldBeNil)
+
+		ret, err := JSONToObjectEx[Base](data)
+		So(err, ShouldBeNil)
+		So(ret, ShouldResemble, val)
+	})
+
+	Convey("实参类型和目标类型本身就是UnionType InternallyTagged", t, func() {
+		type Base interface{}
+		type St1 struct {
+			Metadata `union:"St1"`
+			Type     string
+			Val      string
+		}
+		union := types.NewTypeUnion[Base](St1{})
+		UseTypeUnionInternallyTagged(&union, "Type")
+
+		var val Base = St1{Val: "asd", Type: "St1"}
+		data, err := ObjectToJSONEx(val)
+		So(err, ShouldBeNil)
+
+		ret, err := JSONToObjectEx[Base](data)
+		So(err, ShouldBeNil)
+		So(ret, ShouldResemble, val)
+	})
+
+	Convey("UnionType带有函数 ExternallyTagged", t, func() {
+		union := types.NewTypeUnion[Base](&St1{}, St2{})
+		UseTypeUnionExternallyTagged(&union)
+
+		var val []Base = []Base{
+			&St1{Val: "asd", Type: "St1"},
+			St2{Val: 123, Type: "St2"},
+		}
+		data, err := ObjectToJSONEx(val)
+		So(err, ShouldBeNil)
+
+		ret, err := JSONToObjectEx[[]Base](data)
+		So(err, ShouldBeNil)
+		So(ret, ShouldResemble, val)
+	})
+
+	Convey("UnionType带有函数 InternallyTagged", t, func() {
+		union := types.NewTypeUnion[Base](&St1{}, St2{})
+		UseTypeUnionInternallyTagged(&union, "Type")
+
+		var val []Base = []Base{
+			&St1{Val: "asd", Type: "St1"},
+			St2{Val: 123, Type: "St2"},
+		}
+		data, err := ObjectToJSONEx(val)
+		So(err, ShouldBeNil)
+
+		ret, err := JSONToObjectEx[[]Base](data)
+		So(err, ShouldBeNil)
+		So(ret, ShouldResemble, val)
+	})
+
+	Convey("UnionType，但实际值为nil ExternallyTagged", t, func() {
+		union := types.NewTypeUnion[Base](&St1{}, St2{})
+		UseTypeUnionExternallyTagged(&union)
+
+		var val []Base = []Base{
+			nil,
+		}
+		data, err := ObjectToJSONEx(val)
+		So(err, ShouldBeNil)
+
+		ret, err := JSONToObjectEx[[]Base](data)
+		So(err, ShouldBeNil)
+		So(ret, ShouldResemble, val)
+	})
+
+	Convey("UnionType，但实际值为nil InternallyTagged", t, func() {
+		union := types.NewTypeUnion[Base](&St1{}, St2{})
+		UseTypeUnionInternallyTagged(&union, "Type")
+
+		var val []Base = []Base{
+			nil,
+		}
+		data, err := ObjectToJSONEx(val)
+		So(err, ShouldBeNil)
+
+		ret, err := JSONToObjectEx[[]Base](data)
+		So(err, ShouldBeNil)
+		So(ret, ShouldResemble, val)
+	})
 }
diff --git a/utils/serder/types.go b/utils/serder/types.go
index e6517a9..6c93b71 100644
--- a/utils/serder/types.go
+++ b/utils/serder/types.go
@@ -6,6 +6,8 @@ import (
 	"time"
 )
 
+type Metadata struct{}
+
 type TimestampSecond time.Time
 
 func (t *TimestampSecond) MarshalJSON() ([]byte, error) {
diff --git a/utils/serder/union_handler.go b/utils/serder/union_handler.go
new file mode 100644
index 0000000..bd4df5b
--- /dev/null
+++ b/utils/serder/union_handler.go
@@ -0,0 +1,336 @@
+package serder
+
+import (
+	"fmt"
+	"reflect"
+	"unsafe"
+
+	jsoniter "github.com/json-iterator/go"
+	"github.com/modern-go/reflect2"
+	"gitlink.org.cn/cloudream/common/pkgs/types"
+
+	myreflect "gitlink.org.cn/cloudream/common/utils/reflect"
+)
+
+type TypeUnionExternallyTagged struct {
+	Union          *types.TypeUnion
+	TypeNameToType map[string]reflect.Type
+}
+
+// 遇到TypeUnion的基类（UnionType）的字段时，将其实际值的类型信息也编码到JSON中，反序列化时也会解析出类型信息，还原出真实的类型。
+// Externally Tagged的格式是：{ "类型名": {...对象内容...} }
+//
+// 可以通过内嵌Metadata结构体，并在它身上增加"union"Tag来指定类型名称，如果没有指定，则默认使用系统类型名（包括包路径）。
+func UseTypeUnionExternallyTagged(union *types.TypeUnion) *TypeUnionExternallyTagged {
+	eu := &TypeUnionExternallyTagged{
+		Union:          union,
+		TypeNameToType: make(map[string]reflect.Type),
+	}
+
+	for _, eleType := range union.ElementTypes {
+		eu.Add(eleType)
+	}
+
+	unionHandler.externallyTagged[union.UnionType] = eu
+
+	return eu
+}
+
+func (u *TypeUnionExternallyTagged) Add(typ reflect.Type) error {
+	err := u.Union.Add(typ)
+	if err != nil {
+		return nil
+	}
+
+	u.TypeNameToType[makeDerefFullTypeName(typ)] = typ
+	return nil
+}
+
+type TypeUnionInternallyTagged struct {
+	Union     *types.TypeUnion
+	TagField  string
+	TagToType map[string]reflect.Type
+}
+
+// 遇到TypeUnion的基类（UnionType）的字段时，将其实际值的类型信息也编码到JSON中，反序列化时也会解析出类型信息，还原出真实的类型。
+// Internally Tagged的格式是：{ "类型字段": "类型名", ...对象内容...}，JSON中的类型字段名需要指定。
+// 注：对象定义需要包含类型字段，而且在序列化之前需要手动赋值，目前不支持自动设置。
+//
+// 可以通过内嵌Metadata结构体，并在它身上增加"union"Tag来指定类型名称，如果没有指定，则默认使用系统类型名（包括包路径）。
+func UseTypeUnionInternallyTagged(union *types.TypeUnion, tagField string) *TypeUnionInternallyTagged {
+	iu := &TypeUnionInternallyTagged{
+		Union:     union,
+		TagField:  tagField,
+		TagToType: make(map[string]reflect.Type),
+	}
+
+	for _, eleType := range union.ElementTypes {
+		iu.Add(eleType)
+	}
+
+	unionHandler.internallyTagged[union.UnionType] = iu
+	return iu
+}
+
+func (u *TypeUnionInternallyTagged) Add(typ reflect.Type) error {
+	err := u.Union.Add(typ)
+	if err != nil {
+		return nil
+	}
+
+	// 解引用直到得到结构体类型
+	structType := typ
+	for structType.Kind() == reflect.Pointer {
+		structType = structType.Elem()
+	}
+
+	// 要求内嵌Metadata结构体，那么结构体中的字段名就会是Metadata，
+	field, ok := structType.FieldByName(myreflect.TypeNameOf[Metadata]())
+	if !ok {
+		u.TagToType[makeDerefFullTypeName(structType)] = typ
+		return nil
+	}
+
+	// 为防同名，检查类型是不是也是Metadata
+	if field.Type != myreflect.TypeOf[Metadata]() {
+		u.TagToType[makeDerefFullTypeName(structType)] = typ
+		return nil
+	}
+
+	tag := field.Tag.Get("union")
+	if tag == "" {
+		u.TagToType[makeDerefFullTypeName(structType)] = typ
+		return nil
+	}
+
+	u.TagToType[tag] = typ
+	return nil
+}
+
+type UnionHandler struct {
+	internallyTagged map[reflect.Type]*TypeUnionInternallyTagged
+	externallyTagged map[reflect.Type]*TypeUnionExternallyTagged
+}
+
+func (h *UnionHandler) UpdateStructDescriptor(structDescriptor *jsoniter.StructDescriptor) {
+
+}
+
+func (h *UnionHandler) CreateMapKeyDecoder(typ reflect2.Type) jsoniter.ValDecoder {
+	return nil
+}
+
+func (h *UnionHandler) CreateMapKeyEncoder(typ reflect2.Type) jsoniter.ValEncoder {
+	return nil
+}
+
+func (h *UnionHandler) CreateDecoder(typ reflect2.Type) jsoniter.ValDecoder {
+	typ1 := typ.Type1()
+	if it, ok := h.internallyTagged[typ1]; ok {
+		return &InternallyTaggedDecoder{
+			union: it,
+		}
+	}
+
+	if et, ok := h.externallyTagged[typ1]; ok {
+		return &ExternallyTaggedDecoder{
+			union: et,
+		}
+	}
+
+	return nil
+}
+
+func (h *UnionHandler) CreateEncoder(typ reflect2.Type) jsoniter.ValEncoder {
+	typ1 := typ.Type1()
+	if it, ok := h.internallyTagged[typ1]; ok {
+		return &InternallyTaggedEncoder{
+			union: it,
+		}
+	}
+
+	if et, ok := h.externallyTagged[typ1]; ok {
+		return &ExternallyTaggedEncoder{
+			union: et,
+		}
+	}
+	return nil
+}
+
+func (h *UnionHandler) DecorateDecoder(typ reflect2.Type, decoder jsoniter.ValDecoder) jsoniter.ValDecoder {
+	return decoder
+}
+
+func (h *UnionHandler) DecorateEncoder(typ reflect2.Type, encoder jsoniter.ValEncoder) jsoniter.ValEncoder {
+	return encoder
+}
+
+// 以下Encoder/Decoder都是在传入类型/目标类型是TypeUnion的基类（UnionType）时使用
+type InternallyTaggedEncoder struct {
+	union *TypeUnionInternallyTagged
+}
+
+func (e *InternallyTaggedEncoder) IsEmpty(ptr unsafe.Pointer) bool {
+	return false
+}
+
+func (e *InternallyTaggedEncoder) Encode(ptr unsafe.Pointer, stream *jsoniter.Stream) {
+	var val any
+
+	if e.union.Union.UnionType.NumMethod() == 0 {
+		// 无方法的interface底层都是eface结构体，所以可以直接转*any
+		val = *(*any)(ptr)
+	} else {
+		// 有方法的interface底层都是iface结构体，可以将其转成eface，转换后不损失类型信息
+		val = reflect2.IFaceToEFace(ptr)
+	}
+
+	// 可以考虑检查一下Type字段有没有赋值，没有赋值则将其赋值为union Tag指定的值
+	stream.WriteVal(val)
+}
+
+type InternallyTaggedDecoder struct {
+	union *TypeUnionInternallyTagged
+}
+
+func (e *InternallyTaggedDecoder) Decode(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
+	nextTokenKind := iter.WhatIsNext()
+	if nextTokenKind == jsoniter.NilValue {
+		iter.Skip()
+		return
+	}
+
+	raw := iter.ReadAny()
+	if raw.LastError() != nil {
+		iter.ReportError("decode TaggedUnionType", "getting object raw:"+raw.LastError().Error())
+		return
+	}
+
+	tagField := raw.Get(e.union.TagField)
+	if tagField.LastError() != nil {
+		iter.ReportError("decode TaggedUnionType", "getting type tag field:"+tagField.LastError().Error())
+		return
+	}
+
+	typeTag := tagField.ToString()
+	if typeTag == "" {
+		iter.ReportError("decode TaggedUnionType", "type tag is empty")
+		return
+	}
+
+	typ, ok := e.union.TagToType[typeTag]
+	if !ok {
+		iter.ReportError("decode TaggedUnionType", fmt.Sprintf("unknow type tag %s in union %s", typeTag, e.union.Union.UnionType.Name()))
+		return
+	}
+
+	// 如果目标类型已经是个指针类型*T，那么在New的时候就需要使用T，
+	// 否则New出来的是会是**T，这将导致后续的反序列化出问题
+	if typ.Kind() == reflect.Pointer {
+		val := reflect.New(typ.Elem())
+		raw.ToVal(val.Interface())
+
+		retVal := reflect.NewAt(e.union.Union.UnionType, ptr)
+		retVal.Elem().Set(val)
+
+	} else {
+		val := reflect.New(typ)
+		raw.ToVal(val.Interface())
+
+		retVal := reflect.NewAt(e.union.Union.UnionType, ptr)
+		retVal.Elem().Set(val.Elem())
+	}
+}
+
+type ExternallyTaggedEncoder struct {
+	union *TypeUnionExternallyTagged
+}
+
+func (e *ExternallyTaggedEncoder) IsEmpty(ptr unsafe.Pointer) bool {
+	return false
+}
+
+func (e *ExternallyTaggedEncoder) Encode(ptr unsafe.Pointer, stream *jsoniter.Stream) {
+	var val any
+
+	if e.union.Union.UnionType.NumMethod() == 0 {
+		// 无方法的interface底层都是eface结构体，所以可以直接转*any
+		val = *(*any)(ptr)
+	} else {
+		// 有方法的interface底层都是iface结构体，可以将其转成eface，转换后不损失类型信息
+		val = reflect2.IFaceToEFace(ptr)
+	}
+
+	if val == nil {
+		stream.WriteNil()
+		return
+	}
+
+	stream.WriteObjectStart()
+	valType := myreflect.TypeOfValue(val)
+	if !e.union.Union.Include(valType) {
+		stream.Error = fmt.Errorf("type %v is not in union %v", valType, e.union.Union.UnionType)
+		return
+	}
+	stream.WriteObjectField(makeDerefFullTypeName(valType))
+	stream.WriteVal(val)
+	stream.WriteObjectEnd()
+}
+
+type ExternallyTaggedDecoder struct {
+	union *TypeUnionExternallyTagged
+}
+
+func (e *ExternallyTaggedDecoder) Decode(ptr unsafe.Pointer, iter *jsoniter.Iterator) {
+	nextTkType := iter.WhatIsNext()
+
+	if nextTkType == jsoniter.NilValue {
+		iter.Skip()
+		return
+	}
+
+	if nextTkType != jsoniter.ObjectValue {
+		iter.ReportError("decode UnionType", fmt.Sprintf("unknow next token type %v", nextTkType))
+		return
+	}
+
+	typeStr := iter.ReadObject()
+	if typeStr == "" {
+		iter.ReportError("decode UnionType", "type string is empty")
+	}
+
+	typ, ok := e.union.TypeNameToType[typeStr]
+	if !ok {
+		iter.ReportError("decode UnionType", fmt.Sprintf("unknow type string %s in union %v", typeStr, e.union.Union.UnionType))
+		return
+	}
+
+	// 如果目标类型已经是个指针类型*T，那么在New的时候就需要使用T，
+	// 否则New出来的是会是**T，这将导致后续的反序列化出问题
+	if typ.Kind() == reflect.Pointer {
+		val := reflect.New(typ.Elem())
+		iter.ReadVal(val.Interface())
+
+		retVal := reflect.NewAt(e.union.Union.UnionType, ptr)
+		retVal.Elem().Set(val)
+
+	} else {
+		val := reflect.New(typ)
+		iter.ReadVal(val.Interface())
+
+		retVal := reflect.NewAt(e.union.Union.UnionType, ptr)
+		retVal.Elem().Set(val.Elem())
+	}
+
+	if iter.ReadObject() != "" {
+		iter.ReportError("decode UnionType", "there should be only one fields in the json object")
+	}
+}
+
+func makeDerefFullTypeName(typ reflect.Type) string {
+	realType := typ
+	for realType.Kind() == reflect.Pointer {
+		realType = realType.Elem()
+	}
+	return fmt.Sprintf("%s.%s", realType.PkgPath(), realType.Name())
+}