在Thymeleaf怎么做if-else？ [英] How to do if-else in Thymeleaf?

问题描述

在Thymeleaf中做一个简单的if-else的最佳方法是什么？

What's the best way to do a simple if-else in Thymeleaf?

我想在Thymeleaf中实现与

I want to achieve in Thymeleaf the same effect as

<c:choose>
  <c:when test="${potentially_complex_expression}">
     <h2>Hello!</h2>
  </c:when>
  <c:otherwise>
     <span class="xxx">Something else</span>
  </c:otherwise>
</c:choose>

。

我是什么到目前为止：

<div th:with="condition=${potentially_complex_expression}" th:remove="tag">
    <h2 th:if="${condition}">Hello!</h2>
    <span th:unless="${condition}" class="xxx">Something else</span>
</div>

我不想评估 potential_complex_expression 两次。这就是我引入局部变量条件的原因。

I don't want to evaluate potentially_complex_expression twice. That's why I introduced local variable condition.

我仍然不喜欢同时使用 th：if =$ {condition} 和 th：除非=$ {condition}。

Still I don't like using both th:if="${condition} and th:unless="${condition}".

重要的是我使用了2个不同的html标签：假设 h2 和 span 。

Important thing is that I use 2 different html tags: let's say h2 and span.

你能建议一个更好的方法吗？

Can you suggest a better way to achieve it?

推荐答案

Thymeleaf具有相当于< c：choose> 和< c：when> ： th：切换和 th：case Thymeleaf 2.0中引入的属性。

Thymeleaf has an equivalent to <c:choose> and <c:when>: the th:switch and th:case attributes introduced in Thymeleaf 2.0.

他们按照您的预期工作，使用 * 作为默认情况：

They work as you'd expect, using * for the default case:

<div th:switch="${user.role}"> 
  <p th:case="'admin'">User is an administrator</p>
  <p th:case="#{roles.manager}">User is a manager</p>
  <p th:case="*">User is some other thing</p> 
</div>

参见 http://www.thymeleaf.org/whatsnew20.html#swit 快速解释语法（或百里叶教程）。

See http://www.thymeleaf.org/whatsnew20.html#swit for a quick explanation of syntax (or the thymeleaf tutorials).

免责声明，根据StackOverflow规则的要求：我是百里香的作者。

Disclaimer, as required by StackOverflow rules: I'm the author of thymeleaf.

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