use 'readTree' to parse data file

sample/workdir/subtree1.json

@@ -9,7 +9,7 @@
         "id": 2,
         "name": "Log",
         "args": {
-          "str": "hello"
+          "message": "hello"
         }
       },
       {
@@ -21,5 +21,9 @@
       }
     ]
   },
-  "desc": "子树1"
+  "desc": "子树1",
+  "firstid": 1,
+  "group": [],
+  "import": [],
+  "declvar": []
 }