Support fmt.Stringer for JSON

Author: jinzhu

json.go

@@ -35,16 +35,20 @@ func (j *JSON) Scan(value interface{}) error {
 		return nil
 	}
 	var bytes []byte
-	switch v := value.(type) {
-	case []byte:
-		if len(v) > 0 {
-			bytes = make([]byte, len(v))
-			copy(bytes, v)
+	if s, ok := value.(fmt.Stringer); ok {
+		bytes = []byte(s.String())
+	} else {
+		switch v := value.(type) {
+		case []byte:
+			if len(v) > 0 {
+				bytes = make([]byte, len(v))
+				copy(bytes, v)
+			}
+		case string:
+			bytes = []byte(v)
+		default:
+			return errors.New(fmt.Sprint("Failed to unmarshal JSONB value:", value))
 		}
-	case string:
-		bytes = []byte(v)
-	default:
-		return errors.New(fmt.Sprint("Failed to unmarshal JSONB value:", value))
 	}
 
 	result := json.RawMessage(bytes)