统一返回的状态码
<table>
<thead>
<tr>
<th>code(状态码)</th>
<th>message(说明)</th>
</tr>
</thead>
<tbody>
<tr>
<td>-1</td>
<td>系统错误</td>
</tr>
<tr>
<td>0</td>
<td>成功</td>
</tr>
<tr>
<td>1</td>
<td>失败</td>
</tr>
<tr>
<td>2</td>
<td>参数有误</td>
</tr>
<tr>
<td>4</td>
<td>没有权限</td>
</tr>
</tbody>
</table>