Question

Category.java

@Entity
@Data
@Table(name = "categories")
public class Category implements Serializable{

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;

@NotNull
@Size(min = 5, max = 60)
@Column(name = "category", length = 50, unique = true)
private String category;

@OneToMany
private Set<Product> product;

}

类别Controller.java

@GetMapping("/category/{id}")
public ResponseEntity<List<Product>> getCategoryById(@PathVariable(value = "id") Long categoryId) {
    List<Product> category = productRepository.findAllByCategoryId(categoryId);
    if (category == null) {
        return ResponseEntity.notFound().build();
    }
    return ResponseEntity.ok().body(category);
}

ControllerRepositoy.java

@Repository
public interface CategoryRepository extends JpaRepository<Category,Long>{

}

Products.Java

@Entity
@Data
@Table(name = "products")
public class Product {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @NotNull
    @Size(min = 5, max = 60)
    @Column(name = "productName", length = 50, unique = true, nullable = false)
    private String productName;

    @NotNull
    @Size(min = 10, max = 200)
    @Column(name = "description", length = 200, unique = true, nullable = false)
    private String description;

    @NotNull
    //@Pattern(regexp = "^[0-9]*$")
    @Size(min = 1, max = 10)
    @Column(name = "price", length = 10, unique = true, nullable = false)
    private int price;

    @ManyToOne
    @JoinColumn(name="product")
    private Category categoryId;

    @NotNull
    @Column(name = "imageURL", length = 500, nullable = false)
    private String image;

}

ProductController.java

@RestController
@RequestMapping("/product")
public class ProductController {

    @Autowired
    ProductRepository productRepository;

    @GetMapping("/product")
    public List<Product> getAllNotes() {
        return productRepository.findAll();
    }

    @GetMapping("/product/{id}")
    public ResponseEntity<Optional<Product>> getProductById(@PathVariable(value = "id") Long categoryID) {
        Optional<Product> product = productRepository.findById(categoryID);
        if(product == null) {
            return ResponseEntity.notFound().build();
        }
        return ResponseEntity.ok().body(product);
    }

    @PostMapping("/product")
    public @Valid Product createProduct(@Valid @RequestBody Product product) {
        System.err.println(product);
        return productRepository.save(product);
    }


}

我想使用类别ID查询产品。所以我在categoryController中使用了productRepository。

这是代码。当为GET请求提供Id时，它会显示错误。错误是：

java.lang.IllegalArgumentException: Parameter value [1] did not match expected type [com.susl.Agroapi.model.Category (n/a)]

如何解决？

Answer 1

您必须更改以下代码

将产品实体添加到

@ManyToOne(cascade = CascadeType.DETACH, fetch = FetchType.LAZY)
private Category category;

将类别实体添加到

@OneToMany(mappedBy="category",cascade=CascadeType.REMOVE)
private Set<Product> pr;

制作如下所示的产品库

public interface ProductRepository extends PagingAndSortingRepository<Product, Long>{
    List<Product> findAllProductByCategoryId(@Param("id")Long id);
}

然后，您可以使用带有findAllProductByCategoryId({categoryId})

的ProductRepository通过Controller类调用

Answer 2

您仍未发布请求的ProductRepository，但现在我们至少拥有了Product实体，错误很可能是该方法应该命名

findAllByCategoryIdId

因为您想要按字段id的{{1}}进行搜索。

或者你可以（而且应该）将字段categoryId重命名为categoryId，因为它就是这样的：一个类别，而不是一个ID。

Answer 3

看起来您想要使用CategoryRepository并使用ProductRepository。

创建：

 @Autowired
 CategoryRepository categoryRepository;

Spring引导请求数据

3 个答案: