easyUI 获取Json 嵌套数据

{
userId: "33",
username: "3333",
password: null,
name: "333",
roleId: "3",
groupId: null,
addTime: 1465660800000,
email: "",
phone: "33",
role: {
roleId: "33",
roleName: "33",
remark: "333",
updateTime: 1465660800000
}
}

{field: 'role', title: '角色',
formatter: function (value) {
if(value == null){
return "";
}
return value.roleName;
}
},

{field: 'role.id', title: 'xx',
formatter: function (value, rec) {
return rec.role['id'];
}
},
{field: 'role.name', title: 'xxx',
formatter: function (value, rec) {
return rec.role['name'];
}
},