我尝试了十几种方法在引导程序中垂直居中对齐列但没有工作.我的问题是我不知道然后列的高度.我可以使用flexbox吗?它是否嵌入Bootstrap 3中?

我的代码:
<div class="row">
<div class="col-sm-12">
<div class="col-md-2" style="padding: 0px">
<img alt="img" src="image/avatar/unknown.png" class="img-responsive forum-avatar">
</div>
<div class="col-md-6">
<span class="qap-q-author">user1</span>
<br>
<span class="qap-q-h">test</span>
</div>
<div class="col-md-2">
<span class="text-muted pull-right qap-a-cnt">
<span> </span>
<span class="badge">1</span>
</span>
<span class="qap-q-h pull-right">1</span>
</div>
<div class="col-md-2">
<i class="fa fa-group" style="font-size: 32px"></i>
</div>
</div>
</div>
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