java - Spring Boot 通过 Id 请求数据

Question

分类.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>{

}

产品.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

你必须像下面这样更改代码

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;

像下面这样制作产品库

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

然后您可以通过 Controller 类调用 ProductRepository 和 findAllProductByCategoryId({categoryId})