jsp页面两个不同的实体关联相等

<select id="classid" name="classid">
    <c:forEach items="${AllClass}" var="class_R">
    <c:if test="${student.classid==class_R.classid}">
         <option value="${class_R.classid }" selected>${class_R.classname}</option>
    </c:if>
    <c:if test="${student.classid!=class_R.classid}">
         <option value="${class_R.classid }">${class_R.classname}</option>
    </c:if>
    </c:forEach>
    </select><select id="classid" name="classid">
    <c: