我想把后台传来的这些数据展示到jsp页面上，感觉无从下手 有大神指导吗

代码如下:
<table id="tt" title="Formatting Columns" class="easyui-datagrid" style="width:550px;height:250px"
data-options="url:'/permission/selectuserbyusername',method:'post'"
singleSelect="true" iconCls="icon-save" fitColumns="true"
pagination="true" rownumbers="true">
<thead>
<tr>
<th field="username" width="80">Item ID</th>
<th field="phone" width="80">Product ID</th>
<th field="email" width="80" align="right">Unit Cost</th>
<th field="status" width="60" align="center">Stauts</th>
</tr>
</thead>
</table>
报错:Cannot read property 'length' of undefined