<C:if / Choose /When> 条件的多个实例作为一个答案

【问题标题】：Multiple Instances of <C:if / Choose /When> condition to be made as one<C:if / Choose /When> 条件的多个实例作为一个
【发布时间】：2011-01-25 22:59:12
【问题描述】：

1：我有一个带有多个 html“TR”的 JSP

  <tr>'s

我的页面

  <% ...%>
  <html>
  ...
  <body>
  <table>
  <tr class="1"> This is first line</tr>
  <br/>
  <tr class="2"> This is Second line</tr>
  <br/>
  <tr class="3"> This is Third line</tr>
  <br/>
  <tr class="4"> This is Fourth line</tr>
  <br/>
  <tr class="5"> This is Fifth line</tr>
  <br/>
  ...
  </html>

2：现在我正在获取用户会话（如果已登录）。注意>>：这里使用Liferay主题显示

  <%String userEmail=themeDisplay.getUser().getEmailAddress();%>
  <c:set var="userEmail" value="<%=userEmail%>"></c:set>

3：我检查了它的访客或注册/登录用户。

然后显示更改为登录用户的第一个和最后一个“TR”。

  <% ...%>
  <html>
  ...
  <body>
  <table>
  <c:if test="${not empty userEmail}">      
  <tr class="1"> This is first line for registered user</tr>
  <c:if test="${empty userEmail}">      
  <tr class="1"> This is first line</tr>
  <br/>
  <tr class="2"> This is Second line</tr>
  <br/>
  <tr class="3"> This is Third line</tr>
  <br/>
  <tr class="4"> This is Fourth line</tr>
  <br/>
  <c:if test="${not empty userEmail}">      
  <tr class="5"> This is Fifth line for registered user</tr>
  <c:if test="${empty userEmail}">      
  <tr class="5"> This is Fifth line</tr>
  <br/>
  ...
  </html>

这很好用！！

我的问题>>>>>如果我想将此检查作为某种常量，在 JSP/HTML 页面上不会重复多次。该怎么办？？？

  <c:if> //to be declared only once. And called which ever <TR> needs a check??

【问题讨论】：

标签： java html jsp liferay

【解决方案1】：

一些替代方案：

使用c:set 在页面上设置一个已注册的变量，用于c:choose。


    <c:set var="registered" value="${not empty userEmail}"/>
    <c:choose>
    <c:when test="${registered}">
    <tr class="1"> This is first line for registered user</tr>
    </c:when>
    <c:otherwise>
    <tr class="1"> This is first line</tr>
    </c:otherwise>
    </c:choose>

将第一行和最后一行写为空白表格行，然后使用c:choose 运行 javascript 以插入所需的数据。


    <table>
    <tr id="firstRow"></tr>
    ...
    <tr id="lastRow"></tr>
    </table>

    <c:choose>
    <c:when test="${not empty userEmail}">
    <script>
    document.getElementById('firstRow').innerHTML = 'This is first line for registered user';
    document.getElementById('lastRow').innerHTML = 'This is Fifth line for registered user';
    </script>
    </c:when>
    <c:otherwise>
    <script>
    document.getElementById('firstRow').innerHTML = 'This is first line';
    document.getElementById('lastRow').innerHTML = 'This is Fifth line';
    </script>
    </c:otherwise>
    </c:choose>

【讨论】：