什么相当于简单 scriptlet 代码中的以下代码:
<select name="dropdown">
<option value="one" ${param.dropdown == 'one' ? 'selected' : ''}>One</option>
<option value="two" ${param.dropdown == 'two' ? 'selected' : ''}>Two</option>
<option value="three" ${param.dropdown == 'three' ? 'selected' : ''}>Three</option>
</select>