$(".js-example-tags").select2({ 
     tags: true 
    }) 

<div class="form-group required"> 
    <label class="control-label col-sm-4">测试select2: </label> 
    <div class="col-sm-8"> 
    <form:select path="sett" 
    id="sett" class="form-control required js-example-tags" 
    onchange="onchange('${sett.costAmount}','${sett.id}');"> 
   <form:option value='' label='请选择' />" 
    <form:options items="${fns:findSettList()}" 
    itemLabel="label" itemValue="value" htmlEscape="false" /> 
    </form:select> 
    </div> 
  </div> 

$(".js-example-tags").select2({ 
     tags: true 
    })