英文:
Using dynamic variable in each
问题
I want 0 in images.foo0bar to be replaced by index:
要将images.foo0bar中的0替换为index，可以使用Thymeleaf的内联表达式来实现：
<th:block th:each="someData, index : ${someData.from.somewhere}"><th:block th:each="image : ${images[__${'foo' + index + 'bar'}__]}"><img th:src="${image}"/></th:block><hr/></th:block>
上面的代码中，${'foo' + index + 'bar'}会将0替换为index。注意使用双下划线__来包裹这个表达式以确保它在Thymeleaf中正确解析。
英文:
<th:block th:each="someData, index : ${someData.from.somewhere}"><th:block th:each="image : ${images.foo0bar}"><img th:src="${image}"/></th:block><hr/></th:block>
I want 0 in images.foo0bar to be replaced by index
How do I do something like th:each="image : ${images.foo + index + bar}"
答案1
得分: 4
您可以使用Thymeleaf的预处理器来执行基于串联字符串的getter方法：
<th:block th:each="someData, iterstat : ${someData}"><th:block th:with="imageField=|images.foo${iterstat.index}bar|"><th:block th:each="image : ${__${imageField}__}"><img th:src="${image}"></th:block></th:block></th:block>
在上面的方法中，th:with="imageField=..." 用于构建您所需的字符串：
images.foo0barimages.foo1bar...以此类推...
然后，将该 imageField 变量与Thymeleaf的预处理语法一起使用，将其视为您的 images 对象中的字段名。
更新
我先前的解决方案中有一个错误，如最初写的那样。而不是：
__${imageField}__
应该是：
${__${imageField}__}
换句话说，我忘了将预处理器的结果包装在Thymeleaf表达式中，以便检索每个列表中的实际对象（图像URL）。
我已经进行了更正。
为了背景，这是我用于Thymeleaf模型的测试数据：
List<String> someData = Stream.of("abc", "def", "ghi").collect(Collectors.toList());List<String> a = Stream.of("1", "2", "3").collect(Collectors.toList());List<String> b = Stream.of("4", "5", "6").collect(Collectors.toList());List<String> c = Stream.of("7", "8").collect(Collectors.toList());Images images = new Images();images.setFoo0bar(a);images.setFoo1bar(b);images.setFoo2bar(c);Map<String, Object> model = new HashMap<>();model.put("someData", someData);model.put("images", images);
而且我的 Images 类包含这3个字段：
private List<String> foo0bar;private List<String> foo1bar;private List<String> foo2bar;
只是一个建议...
支持这一点的Java对象似乎有点复杂，背后的实现也不太直接。
您有一个 someData 集合，您不会直接访问它，只是用来迭代其内容的计数。
然后，您使用这个计数来构建一个字段名，以便执行相关的getter方法，然后迭代完全不同（似乎无关）对象中的图像URL集合。
只是一个建议：如果重新排列您的Java数据，您可以避免这种Thymeleaf的复杂性。
英文:
You can use Thymeleaf's preprocessor to execute a getter based on a concatenated string:
__${...}__
For example:
<th:block th:each="someData, iterstat : ${someData}"><th:block th:with="imageField=|images.foo${iterstat.index}bar|"><th:block th:each="image : ${__${imageField}__}"><img th:src="${image}"></th:block></th:block></th:block>
In the above approach, the th:with="imageField=..." is used to build the string you need:
images.foo0barimages.foo1bar... and so on...
That imageField variable is then used with the Thymeleaf preprocessing syntax to handle it as a field name in your images object.
UPDATE
My solution above had a mistake, as originally written. Instead of this:
__${imageField}__
It should be this:
${__${imageField}__}
In other words, I forgot to wrap the pre-processor results in a Thymeleaf expression - so that the actual objects in each list (of image URLs) are retrieved.
I corrected this, above.
For backgound, here is the test data I used for the Thymeleaf model:
List<String> someData = Stream.of("abc", "def", "ghi").collect(Collectors.toList());List<String> a = Stream.of("1", "2", "3").collect(Collectors.toList());List<String> b = Stream.of("4", "5", "6").collect(Collectors.toList());List<String> c = Stream.of("7", "8").collect(Collectors.toList());Images images = new Images();images.setFoo0bar(a);images.setFoo1bar(b);images.setFoo2bar(c);Map<String, Object> model = new HashMap<>();model.put("someData", someData);model.put("images", images);
And my Images class contains these 3 fields:
private List<String> foo0bar;private List<String> foo1bar;private List<String> foo2bar;
Just a suggestion...
The Java objects which support this appear to be a bit convoluted, behind the scenes.
You have a collection of someData which you do not directly access, except to iterate through a count of its contents.
You then use this count to build a field name, so you can executed the related getter - and iterate through that collection of image URLs, in a completely different (seemingly unrelated) object.
Just as a suggestion: If you re-arrange your Java data, you could avoid this Thymeleaf complexity.
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