Issue
I can't seem to find the error in my code. All my imports are fine. Everything seems in order but when I click the add new button, I get the error, "Neither BindingResult nor plain target object for bean name 'product' available as request attribute". Also, if I change the bean name to products in my Get and Post Mapping request along with making the same change in the add file, it works.
Here's my add.html file:
<!doctype html>
<nav th:replace="/fragments/nav :: nav-admin"></nav>
<div class="container">
<h1 class="display-2">Add a product</h1>
<a href="/admin/products" class="btn btn-primary mt-4 mb-4">Back to Products</a>
<div th:if="${message}" th:text="${message}" th:class="${'alert ' + alertClass}"></div>
<form method="post" th:object="${product}" th:action="@{/admin/products/add}" enctype="multipart/form-data">
<div th:if="${#fields.hasErrors('*')}" class="alert alert-danger">
There are errors
</div>
<div class="form-group">
<label for="">Name</label>
<input type="text" class="form-control" th:field="*{name}" placeholder="Name">
<span class="error" th:if="${#fields.hasErrors('name')}" th:errors="*{name}"></span>
</div>
<div class="form-group">
<label for="">Description</label>
<textarea th:field="*{description}" rows="10" class="form-control" placeholder="Description"></textarea>
<span class="error" th:if="${#fields.hasErrors('description')}" th:errors="*{description}"></span>
</div>
<div class="form-group">
<label for="">Image</label>
<input type="file" class="form-control" th:name="file" th:id="file">
<img class="mt-2" src="#" alt="" id="imgPreview1">
</div>
<div class="form-group">
<label for="">Price</label>
<input type="text" class="form-control" th:field="*{price}" placeholder="20 or 20.99">
<span class="error" th:if="${#fields.hasErrors('price')}" th:errors="*{price}"></span>
</div>
<div class="form-group">
<label for="">Category</label>
<select th:field="*{categoryId}" class="form-control">
<option th:value="0">Choose a category</option>
<option th:each="cat: ${categories}" th:value="${cat.id}" th:text="${cat.name}"></option>
</select>
<span class="error" th:if="${#fields.hasErrors('categoryId')}" th:errors="*{categoryId}"></span>
</div>
<button class="btn btn-danger mt-4 mb-4">Add</button>
</form>
</div>
<div th:replace="/fragments/footer"></div>
My model name is Products.java and here is the Controller code for GET and POST for add
@GetMapping("/add")
public String add(Products product, Model model) {
List<Category> categories = categoryRepo.findAll();
model.addAttribute("categories", categories);
return "admin/products/add";
}
@PostMapping("/add")
public String add(@Valid Products product, BindingResult bindingResult,
MultipartFile file, RedirectAttributes redirectAttributes,
Model model) throws IOException {
List<Category> categories = categoryRepo.findAll();
if (bindingResult.hasErrors()) {
model.addAttribute("categories", categories);
return "admin/products/add";
}
boolean fileOK = false;
byte[] bytes = file.getBytes();
String filename = file.getOriginalFilename();
Path path = Paths.get("src/main/resources/static/media/" + filename);
if (filename.endsWith("jpg") || filename.endsWith("png") ) {
fileOK = true;
}
redirectAttributes.addFlashAttribute("message", "Product added");
redirectAttributes.addFlashAttribute("alertClass", "alert-success");
String slug = product.getName().toLowerCase().replace(" ", "-");
Products productExists = productRepo.findBySlug(slug);
if (! fileOK ) {
redirectAttributes.addFlashAttribute("message", "Image must be a jpg or a png");
redirectAttributes.addFlashAttribute("alertClass", "alert-danger");
redirectAttributes.addFlashAttribute("product", product);
}
else if ( productExists != null ) {
redirectAttributes.addFlashAttribute("message", "Product exists, choose another");
redirectAttributes.addFlashAttribute("alertClass", "alert-danger");
redirectAttributes.addFlashAttribute("product", product);
} else {
product.setSlug(slug);
product.setImage(filename);
productRepo.save(product);
Files.write(path, bytes);
}
return "redirect:/admin/products/add";
}
Solution
You need to add to the model, in the get mapping method, an attribute with name 'product' that represents the form. Spring MVC Form tutorial
@GetMapping("/add")
public String add(Model model) {
List<Category> categories = categoryRepo.findAll();
model.addAttribute("categories", categories);
model.addAttribute("product", new Products());
return "admin/products/add";
}
Answered By - JorgeB
