我尽了最大努力找到解决方案，但我不能，我试图让用户选择一个类别名称，并基于此选择，它将加载与此类别相关的产品属性。
我可以加载类别和产品，但我不能根据类别和产品的价格加载产品，我需要它被显示，但用户不能改变价格。
CartItem控制器:
@Controller
public class CartItemsControllers {
@Autowired
private CartItemService shoppingCartService;
@Autowired
private CustomerService customerService;
@Autowired
private ProductRepository productRepository;
public CartItemsControllers(CartItemService shoppingCartService, CustomerService customerService, ProductRepository productRepository) {
this.shoppingCartService = shoppingCartService;
this.customerService = customerService;
this.productRepository = productRepository;
}
//Model
@ModelAttribute("cartItem")
public CartItem cartItem()
{
return new CartItem();
}
@ModelAttribute("product")
public List<Products> initializeprodcuts(){
List<Products> products = productRepository.findAll();
return products ;
}
//create form
@GetMapping("/cart/create")
public String createCartItem(Model model)
{
CartItem cartItem = new CartItem();
model.addAttribute("cartItem",cartItem);
return "MakeABill";
}
//Save
@PostMapping("/cart/save")
public String saveCartItem(@ModelAttribute("cartItem") CartItem cartItem)
{
shoppingCartService.saveCart(cartItem);
return "MakeABill";
}
@GetMapping("/products/{categoryId}")
public List<Products> getCategoriesProducts(@PathVariable Long categoryId)
{
return productRepository.findByCategoriesId(categoryId);
}
CartItem实体:
@Entity
@Table(name="cart_items")
@AllArgsConstructor
public class CartItem {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long cart_item_id;
@Temporal(TemporalType.DATE)
private Date date;
private int product_quantity;
@OneToMany(fetch = FetchType.LAZY,mappedBy = "product_id")//this column is the foreign key
private Set<Products> product = new HashSet<>();
public Date getDate() {
return date;
}
public CartItem()
{
}
产品实体类:
public class Products {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long product_id;
private String product_name;
private double product_price;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "categories_id") //the name of the column in the other class and that name will be a column in the class
private Categories product_category;
private String product_quantity;
private String product_Section;
private String product_ExpDate;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "cart_item_id") //the name of the column in the other class and that name will be a column in the class
private CartItem cartItem;
ProductRepository:
@Repository
public interface ProductRepository extends JpaRepository<Products, Long> {
List<Products> findByCategoriesId(Long categoriesId);
}
Make A Bill HTML PAGE:
<form th:action="@{/cart/save}" method="post" th:object="${cartItem}">
<div class="row g-3">
<div class="col-12">
<h4 class="mb-3">Select A Product</h4>
<br>
<label th:for="category"> Category : </label>
<select class="form-control form-control-sm" id="category" autofocus th:change="getProducts()"> <!-- the name of the variable -->
<option value="">Select Category</option>
<!-- ${product} this is the model attribute -->
<!-- th:value="${product.categories_id}" value here is the id-->
<!-- th:text="${category.categoryName}" text is what i want to be shown that eqauls to the id-->
<!--<option th:each = "product: ${product}"
th:value="${product.product_category.categories_id}"
th:text="${product.product_category.categoryName}"
></option>-->
</select>
<br>
<label th:for="product"> Product Name : </label>
<select class="form-control form-control-sm" id="product" autofocus>
<option value="">Select Product</option>
<option th:each = "product: ${product}"
th:value="${product.product_name}"
th:text="${product.product_name}"
>
</option>
</select>
<br>
<label th:for="product_price"> Product Price : </label>
<input class="form-control form-control-sm" id="product_price" th:value="${product_name}" th:text="${product_price}" disabled >
<br>
<label th:for="roles"> Product Quantity : </label>
<input class="form-control form-control-sm" id="product_quantity" th:field="*{product_quantity}" autofocus>
<br>
<button class="w-5 btn btn-primary " type="submit" id="add_submit">Add </button>
</div>
</div>
</form>
<script>
function getProducts(){
//get the category id
var categoryId = $('#category').val();
$.get("/products/" + categoryId, function(data){
var option = "";
$.each(data, function (key, value) {
option += "<option value = " + value.id + ">" + value.product_name + "</option>";
});
$("#product").find('option').remove().end().append(option);
});
}
</script>
这里出现错误:
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'cartItemsControllers' defined in file [E:Spring BootwarehouseManagementSystemtargetclassescomexamplewarehouseManagementSystemControllersCartItemsControllers.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'shoppingCartImp': Unsatisfied dependency expressed through field 'productRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productRepository' defined in com.example.warehouseManagementSystem.Repository.ProductRepository defined in @EnableJpaRepositories declared on JpaRepositoriesRegistrar.EnableJpaRepositoriesConfiguration: Invocation of init method failed; nested exception is org.springframework.data.repository.query.QueryCreationException: Could not create query for public abstract java.util.List com.example.warehouseManagementSystem.Repository.ProductRepository.findByCategoriesId(java.lang.Long)! Reason: Failed to create query for method public abstract java.util.List com.example.warehouseManagementSystem.Repository.ProductRepository.findByCategoriesId(java.lang.Long)! No property categoriesId found for type Products!; nested exception is java.lang.IllegalArgumentException: Failed to create query for method public abstract java.util.List com.example.warehouseManagementSystem.Repository.ProductRepository.findByCategoriesId(java.lang.Long)! No property categoriesId found for type Products!
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:229) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1372) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1222) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:944) ~[spring-beans-5.3.10.jar:5.3.10]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.10.jar:5.3.10]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.10.jar:5.3.10]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.5.5.jar:2.5.5]
您可以像下面这样使用jQuery根据所选的类别填充产品
function getProducts(){
//get the category id
var categoryId = $('#category').val();
$.get("/products/" + categoryId, function(data){
var option = "";
$.each(data, function (key, value) {
option += "<option value = " + value.id + ">" + value.product_name + "</option>";
});
$("#product").find('option').remove().end().append(option);
});
}
使用
调用getProducts()方法<select id="category" th:change="getProducts()">
定义一个Rest API端点"/products/{categoryId}"，它返回给定categoryId的产品列表，如下所示
编辑1
@Controller
class CategoryController{
@AutoWired
private ProductRepository productRepository;
@GetMapping("/products/{categoryId}")
@ResponseBody
public List<Products> listProducts(@PathVariable long categoryId){
return this.productRepository.findByProduct_category(categoryId);
}
}