JavaWeb中c:if根据参数action的值,显示不同的星期欢迎信息

可以使用 JSTL（JSP标准标记库）中的 c:choose 和 c:when 标签来实现该功能。具体代码如下：

<c:choose>
  <c:when test="${param.action == 'Monday'}">
    <p>Welcome to Monday!</p>
  </c:when>
  <c:when test="${param.action == 'Tuesday'}">
    <p>Welcome to Tuesday!</p>
  </c:when>
  <c:when test="${param.action == 'Wednesday'}">
    <p>Welcome to Wednesday!</p>
  </c:when>
  <c:when test="${param.action == 'Thursday'}">
    <p>Welcome to Thursday!</p>
  </c:when>
  <c:when test="${param.action == 'Friday'}">
    <p>Welcome to Friday!</p>
  </c:when>
  <c:when test="${param.action == 'Saturday'}">
    <p>Welcome to Saturday!</p>
  </c:when>
  <c:when test="${param.action == 'Sunday'}">
    <p>Welcome to Sunday!</p>
  </c:when>
  <c:otherwise>
    <p>Welcome!</p>
  </c:otherwise>
</c:choose>

该代码根据参数 action 的值来显示不同的欢迎信息，如果参数 action 不是上述星期的任何一个，就显示默认的欢迎信息。