jsp - jSTL if else choose/when not evaluating variables

Question

我正在尝试在满足选择/满足条件时打印一些 html:

 <c:choose>
      <c:when test="${notification.placeId} == ${place.placeId}">
    ${notification.name}
  </c:when>
<c:otherwise>
    placeId: ${place.placeId} - notplaceid: ${notification.placeId}
    </c:otherwise>
 </c:choose>

这会打印: placeId: 50 - notplaceid: 43 placeId: 50 - notplaceid: 47 placeId: 50 - notplaceid: 49 placeId: 50 - notplaceid: 50 placeId: 50 - notplaceid: 51 placeId : 50 - notplaceid: 51 placeId: 50 - notplaceid: 51 placeId: 50 - notplaceid: 51 placeId: 50 - notplaceid: 52 placeId: 50 - notplaceid: 53 placeId: 50 - notplaceid: 0 placeId: 50 - notplaceid: 0

这一切都从 otherwise 打印出来，从不打印 when 语句中的通知名称。从打印中可以看出，粗体输出显然满足 when 条件，应该打印通知名称。

有人知道这是怎么回事吗？

Answer 1

使用

<c:when test="${notification.placeId == place.placeId}">

代替

<c:when test="${notification.placeId} == ${place.placeId}">

按照您输入的方式，test 属性被评估为一个字符串:${notification.placeId} 评估结果的串联，==，以及${place.placeId}的求值结果。

你希望整个事情都被评估为一个 bool 表达式。