Thymeleaf中使用if和unless实现状态的判断显示达到if-else逻辑判断的效果

川长思鸟来 2023-10-18 18:37 74阅读 0赞

## 场景 ##

Thymeleaf官方文档：

[https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html\#introducing-thymeleaf][https_www.thymeleaf.org_doc_tutorials_3.0_usingthymeleaf.html_introducing-thymeleaf]

官方文档说明：

有时，只有在满足特定条件时，才需要显示模板的片段。

官方使用示例：

<table>
      <tr>
        <th>NAME</th>
        <th>PRICE</th>
        <th>IN STOCK</th>
        <th>COMMENTS</th>
      </tr>
      <tr th:each="prod : ${prods}" th:class="${prodStat.odd}? 'odd'">
        <td th:text="${prod.name}">Onions</td>
        <td th:text="${prod.price}">2.41</td>
        <td th:text="${prod.inStock}? #{true} : #{false}">yes</td>
        <td>
          <span th:text="${#lists.size(prod.comments)}">2</span> comment/s
          <ahref = "comments.html"<BR>        th:href="@{/product/comments(prodId=${prod.id})}"
             th:if="${not #lists.isEmpty(prod.comments)}">view</a>
        </td>
      </tr>
    </table>

注意：

th:if属性不仅计算布尔型数据，还能计算表达式的值为true时也遵守如下规则：

1.如果值为NULL：

则th:if将计算为false

2.如果值不为NULL:

①值为布尔型，为true。

②值为数字，为非0。

③值为字符，为非0。

④值为字符串，不为“false”、"off"、“no”

还有，th:if有一个逆属性，th:unless,除非。。。

官方举例：

## 实现 ##

<div class="form-group col-md-4 ml_10"><label>业务物流类型:</label>
                                <input type="text" th:value="物料清洁上料" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='01'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="托盘清洁上料" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='02'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="托盘清洁上台" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='03'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="废料包材出库" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='04'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="废料托盘出库" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='05'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="不良品出库" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='06'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="清洁设备补盘" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='07'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="待清洁入库" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='08'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="不良品暂估" th:if="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='09'}" readonly="readonly" class="form-control"/>
                                <input type="text" th:value="未知状态" th:unless="${detailsVO==null || detailsVO.orderType ==null ?'':detailsVO.orderType=='01'||detailsVO.orderType=='02'||detailsVO.orderType=='03'||detailsVO.orderType=='04'||detailsVO.orderType=='05'||detailsVO.orderType=='06'||detailsVO.orderType=='07'||detailsVO.orderType=='08'||detailsVO.orderType=='09'}" readonly="readonly" class="form-control"/>
                            </div>

[https_www.thymeleaf.org_doc_tutorials_3.0_usingthymeleaf.html_introducing-thymeleaf]: https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#introducing-thymeleaf