在使用elementui框架上传组件的时候，出现session丢失，后端无法获取到sessionid，导致返回状态为未登陆
查看请求头缺少cookie值
上传组件代码：
<el-upload
class="upload-demo"
ref="upload"
:action="action_url"
:on-preview="handlePreview"
:on-remove="handleRemove"
:before-remove="beforeRemove"
:data="uploadParams"
name="file"
:multiple='false'
:limit="1"
:on-exceed="handleExceed"
:on-success="uploadSuc"
:file-list="fileList"
:auto-upload="false">
<el-button size="small" type="primary">选择文件</el-button>
<div slot="tip" class="el-upload__tip">请上传后缀为.txt文件,文件每行一条记录</div>
</el-upload>
解决方法：
设置属性with-credentials为true支持发送 cookie 凭证信息
修改后el-upload代码：
<el-upload
class="upload-demo"
ref="upload"
:action="action_url"
:on-preview="handlePreview"
:on-remove="handleRemove"
:before-remove="beforeRemove"
:data="uploadParams"
name="file"
:multiple='false'
:with-credentials='true'
:limit="1"
:on-exceed="handleExceed"
:on-success="uploadSuc"
:file-list="fileList"
:auto-upload="false">
<el-button size="small" type="primary">选择文件</el-button>
<div slot="tip" class="el-upload__tip">请上传后缀为.txt文件,文件每行一条记录</div>
</el-upload>
最后，查看请求头，可以看到有cookie值，文件上传成功
