diff --git a/single_file_tests/json.go b/single_file_tests/json.go
index 744c10a..e29ea45 100644
--- a/single_file_tests/json.go
+++ b/single_file_tests/json.go
@@ -1,20 +1,45 @@
 package main
 
 import (
-    "encoding/json"
+	"encoding/json"
+	"strconv"
     "fmt"
 )
 
-type Test struct {
-	Name      string `json:"name"`
-	Name2     string `json:"name2"`
-	Name3     string `json:"name3,omitempty"`
-	Age       int32  `json:"age"`
-	NotSer    string `json:"-"`
-	Bool      bool   `json:"bool"`
-	BoolInStr bool   `json:"bool_in_str,string"`
+type TheLong struct {
+	Value     int64
 }
 
+type Test struct {
+	Name      string  `json:"name"`
+	Name2     string  `json:"name2"`
+	Name3     string  `json:"name3,omitempty"`
+	Age       int32   `json:"age"`
+	NotSer    string  `json:"-"`
+	Bool      bool    `json:"bool"`
+	BoolInStr bool    `json:"bool_in_str,string"`
+	Long      int64   `json:"long"`
+	Long2     TheLong `json:"long2"`
+}
+
+// https://www.cnblogs.com/yorkyang/p/8990570.html
+func (l *TheLong) MarshalJSON() (data []byte, err error) {
+	fmt.Println("------")//??
+    if l != nil {
+        data = []byte(strconv.FormatInt(l.Value, 10))
+    }
+    return
+}
+func (l *TheLong) UnmarshalJSON(data []byte) error {
+	v, err := strconv.ParseInt(string(data), 10, 64)
+	if err != nil {
+		return err
+	}
+	l.Value = v
+    return nil
+}
+ 
+
 func main() {
 	t := Test {
 		Name: "hatter",
@@ -24,6 +49,8 @@ func main() {
 		NotSer: "not ser!",
 		Bool: true,
 		BoolInStr: true,
+		Long: 342438204823084023,
+		Long2: TheLong { Value: 1111111111111111111 },
 	}
 	s, err := json.Marshal(t)
 	if err != nil {