Datatable正在运行，但它没有显示导出按钮
$(document).ready(function() {
$('#table').DataTable( {
dom: 'Bfrtip',
buttons: ['copyHtml5',
'excelHtml5',
'csvHtml5',
'pdfHtml5'
]
} );} );
这些是导入
<link rel="stylesheet" type="text/css" href="https://cdn.datatables.net/v/dt/dt-1.10.16/b-1.5.1/b-colvis-1.5.1/b-flash-1.5.1/b-html5-1.5.1/r-2.2.1/datatables.min.css"/>
<script type="text/javascript" src="https://cdn.datatables.net/v/dt/dt-1.10.16/b-1.5.1/b-colvis-1.5.1/b-flash-1.5.1/b-html5-1.5.1/r-2.2.1/datatables.min.js"></script>
<script type="text/javascript" src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script src="https://cdn.datatables.net/1.10.16/js/jquery.dataTables.min.js"></script>
<link rel="stylesheet" type="text/css" href="https://cdn.datatables.net/1.10.16/css/jquery.dataTables.min.css">
<link rel="stylesheet" type="text/css" href=" https://cdn.datatables.net/buttons/1.5.1/css/buttons.dataTables.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.3.5/jspdf.debug.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.3/css/bootstrap.min.css">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.3/js/bootstrap.min.js" integrity="sha384-a5N7Y/aK3qNeh15eJKGWxsqtnX/wWdSZSKp+81YjTmS15nvnvxKHuzaWwXHDli+4" crossorigin="anonymous"></script>