list:[{
"id": "762ea315543640f59eddd169b32597dc",
"create_date": "2016-11-28 17:19:31",
"modify_date": "2016-11-28 17:19:31",
"grade": 0,
"name": "李持缨",
"order_id": 6,
"parent_id": "c417b4c62c004188aa7cfa1956b90edd",
"tree_path": null,
"is_menu": "1",
"url": null,
"allow_article": "1",
"menu_type": 1,
"old_name": null
}, {
"id": "c417b4c62c004188aa7cfa1956b90edd",
"create_date": "2016-11-29 21:59:28",
"modify_date": "2016-11-29 21:59:28",
"grade": 1,
"name": "中心领导",
"order_id": 1,
"parent_id": "ed60c5760e684f9ab4113698c9a2c5d4",
"tree_path": "ed60c5760e684f9ab4113698c9a2c5d4",
"is_menu": "1",
"url": null,
"allow_article": "1",
"menu_type": 1,
"old_name": null
}, {
"id": "ed60c5760e684f9ab4113698c9a2c5d4",
"create_date": "2016-11-28 16:25:04",
"modify_date": "2016-11-28 16:25:04",
"grade": 0,
"name": "市投资公司",
"order_id": 1,
"parent_id": null,
"tree_path": null,
"is_menu": "1",
"url": null,
"allow_article": "1",
"menu_type": 1,
"old_name": null
}]list.get(i):{
"id": "762ea315543640f59eddd169b32597dc",
"create_date": "2016-11-28 17:19:31",
"modify_date": "2016-11-28 17:19:31",
"grade": 0,
"name": "李持缨",
"order_id": 6,
"parent_id": "c417b4c62c004188aa7cfa1956b90edd",
"tree_path": null,
"is_menu": "1",
"url": null,
"allow_article": "1",
"menu_type": 1,
"old_name": null
}
点属性取值,就抛这个异常了