html 元素的条件显示，使用 jsp

Question

我想根据从数据库中读取的布尔值显示第二个密码输入字段。从数据库读取的代码已经写好了，而且可以运行。我遇到的问题是列表元素的条件显示。我知道的很少 jsp - 用谷歌搜索答案，并得出以下结果，不起作用。代码：

   <ul>
    <li><label for="username">Username</label>
     <input type="username" name="username" placeholder="username" required>
    </li>
    <li><label for="password">Password</label>
     <input type="password" name="password" placeholder="password" required>
    </li>
    <!-- conditional display of a second password field -->
    <% 
     if (@showDoublePasswords == true) { 
    %>
     <li><label for="password">Password 2</label>
      <input type="password" name="password" placeholder="password" required>
     </li>
     
    <% } %>
            </ul>

Answer 1

试试这个

<ul>
                <li><label for="username">Username</label>
                    <input type="username" name="username" placeholder="username" required>
                </li>
                <li><label for="password">Password</label>
                    <input type="password" name="password" placeholder="password" required>
                </li>
                <!-- conditional display of a second password field -->
                <% 
                    //Remove '@' 
                    if (showDoublePasswords == true) 
                    { 
                %>
                      <li><label for="password">Password 2</label>
                          <input type="password" name="password" placeholder="password" required>
                    </li>

                <% } 
                %>
            </ul>

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html 元素的条件显示，使用 jsp

conditional display of an html element, using jsp

html

conditional

jsp

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