属性或字段'products'在空 th：each 上找不到

Question

我在百里香叶上有问题

这是我的产品控制器：

@GetMapping(path = "/search_results")
public String search(@RequestParam(value = "search", required = false) String search, Model model){
List<Product> productList = productRepository.findAll();
for (Product product : productList) {
System.out.println("Product ID: " + product.getID_product());
if (product.getProdName().contains(search) || product.getProdBrand().contains(search)){
model.addAttribute("price", product.getPrice());
System.out.println("Price: " + product.getPrice());
model.addAttribute("prodName", product.getProdName());
System.out.println("Name: " + product.getProdName());
model.addAttribute("category_name", product.getCategory().getCategory_name());
System.out.println("Category: " + product.getCategory().getCategory_name());
model.addAttribute("prodDesc", product.getProdDesc());
model.addAttribute("prodImage", product.getProdImage());
model.addAttribute("prodBrand", product.getProdBrand());
}
}
return "search_results";
}

这是我的html上的一些片段： 搜索框：

<form method="get" action="/search_results" th:action="@{/search_results}" th:object="${productController}"/>
<input th:text="${search}" class="col-8.5" type="text" id="search" name="search"
placeholder="Search for Products and Brands">
<input id="searchButton" class="navbar-toggler" type="submit" value="Search"/>
</form>

和搜索结果卡：

<div class="card h-20">
<a th:href="@{/item_details}"><img class="card-img-top" th:blob="${prodImage}" alt="image"></a>
<div class="card-body" th:each="product : *{products}">
<h4 class="card-title">
<a th:href="@{/item_details}" th:text="${product.prodName}"/>
</h4>
Rp:
<span text="price" th:text="${product.price}"/><br>
Category:
<a text="category_name" th:text="${product.category_name}" name="category_name"/>
</div>
<div class="card-footer">
<small class="text-muted">&#9733; &#9733; &#9733; &#9733; &#9734;</small>
</div>
</div>

但是当我输入搜索项目时，它出现此错误：

org.springframework.expression.spel.SpelEvaluationException: EL1007E: Property or field 'products' cannot be found on null.

我做错了什么？

Answer 1

您忘记在模型属性中插入产品。 你的控制器中应该有类似的东西

List<Product> productList = productRepository.findAll();
model.addAttribute("products", productList);