解决使用elementUI框架el-upload上传组件时session丢失问题

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