Spring UnsatisfiedDependencyException 并且不是托管类型：class java.lang.Object

Question

我想为两个域对象创建一个通用存储库class：产品和类别，并能够列出 index.html 中的所有元素。

这是我的代码：

@Controller
public class IndexController {

private final ProdCatService<Category> categoryProdCatService;

public IndexController(ProdCatService<Category> categoryProdCatService) {
    this.categoryProdCatService = categoryProdCatService;
}

@RequestMapping({"","/","index"})
public String getIndexPage(Model model)
{       
    model.addAttribute("cat", categoryProdCatService.getAll());
    return "index";
}
}

存储库：

public interface ProdCatRepository<T> extends CrudRepository<T, Long> { }

服务：

public interface ProdCatService<T> {

Set<T> getAll();
T findById(Long id);
}


@Service
public class ProdCatServiceImpl<T> implements ProdCatService {

private final ProdCatRepository<T> prodCatRepository;

public ProdCatServiceImpl(ProdCatRepository<T> prodCatRepository) {
    this.prodCatRepository = prodCatRepository;
}

@Override
public Set<T> getAll() {
    Set<T> productsSet = new HashSet<>();
    prodCatRepository.findAll().iterator().forEachRemaining(productsSet::add);
    return productsSet;
}

@Override
public T findById(Long id) {
    return prodCatRepository.findById(id).get();
}
}

所以问题是我遇到了很多错误，例如：

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'indexController' defined in file [C:\Users\Michał\Documents\webstore-v-1\target\classes\info\mike\webstorev1\controllers\IndexController.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'prodCatServiceImpl' defined in file [C:\Users\Michał\Documents\webstore-v-1\target\classes\info\mike\webstorev1\service\ProdCatServiceImpl.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'prodCatRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object

和

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'prodCatRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object

我正在寻求帮助。我查看了 S/O，但找不到答案。

编辑类别域 class。

@Entity
public class Category {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String categoryName;

@ManyToMany(mappedBy = "categories")
private Set<Product> products;

@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((id == null) ? 0 : id.hashCode());
    return result;
}

@Override
public boolean equals(Object obj) {
    if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    Category other = (Category) obj;
    if (id == null) {
        if (other.id != null)
            return false;
    } else if (!id.equals(other.id))
        return false;
    return true;
}

Answer 1

I want to create a generic repository class for two domain objects: Product and Category and be able to list all elements in index.html.

你的要求没有意义。
要实现它，您应该在 Product 和 Category 之间定义一个基础 class，并在通用存储库中指定这个基础 class。
类别是不同于产品的概念。
因此，但是通过扭曲层次结构，您将无法定义此基础 class.
即使您定义了它，它也不会反映类别和产品中都需要的字段。
那么在这些情况下，您希望如何在客户端正确列出它们？

那你为什么要重新发明轮子？
实际上你使用 Spring 数据来减少样板代码：

public interface ProdCatRepository<T> extends CrudRepository<T, Long> { }

很清楚，也很容易申报。
不要试图通过关联不应该的事物并为每个事物定义一个不同的存储库来变得太聪明：

public interface ProductRepository extends CrudRepository<Product, Long> { }
public interface CategoryRepository extends CrudRepository<Category, Long> { }

Spring UnsatisfiedDependencyException 并且不是托管类型：class java.lang.Object

Spring UnsatisfiedDependencyException and Not a managed type: class java.lang.Object

java

spring

java.lang