java - Spring 启动: Reading data using Spring Data JPA returns incorrect values

Question

我在我的应用程序中使用 Spring Boot。我有一个访问服务层的 Controller ，该服务层访问 Spring Data JPA 的 CrudRepository 的实现，该实现与 Hibernate 交互以从数据库获取数据。 CrudRepository 的以下所有三个实现都返回错误的对象:

public class ProductRepositoryImpl implements ProductRepository {

    @Autowired
    private SessionFactory sessionFactory;

    @SuppressWarnings("unchecked")
    public List<Product> findProductBatch(int start, int end) {
        Session session = sessionFactory.getCurrentSession();
        Query query = session.createQuery("from Product");
        query.setFirstResult(start);
        query.setMaxResults(end);
        List<Product> list = query.list();
        return list;
    }

    @SuppressWarnings({ "unused", "unchecked" })
    @Override
    public Iterable<Product> findAll() {
        Session session = sessionFactory.getCurrentSession();
        List<Product> products = session.createQuery("from Product").list();
        Iterable<Product> productIterable = products;
        return products;
    }

    @SuppressWarnings("unchecked")
    public List<Product> findBatch(int start, int end) {
        Session session = sessionFactory.getCurrentSession();
        Query query = session.createQuery("from Product");
        query.setFirstResult(start);
        query.setMaxResults(end);
        List<Product> list = query.list();
        return list;
    }

}

仅当传递给 findOne() 方法的参数为零且记录的 id 不为零时，findOne() 方法才会返回一条记录。发送请求时返回以下 JSON 响应:

{
  "productId": 0,
  "name": "xxxxxx",
  "productCategoryId": null,
  "created": 1482655958000,
  "createdBy": null
}

该记录存在于数据库中，但其 id 为 1，并且确实有一个“productCategoryId”，但由于未注入(inject)，因此返回 null。

findAll() 方法返回重复多次的同一记录，findBatch() 方法返回类似的响应。

这是其余的代码:

产品.java:

@Entity
public class Product {

    @Id
    private Integer productId;
    private String name;
    private Integer productCategoryId;
    @OneToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "productCategoryId", insertable = false, updatable = false)
    @Autowired
    private ProductCategory productCategory;
    private Date created;
    private Integer createdBy;

    public Product() {
    }

    public Product(Integer productId, String name, ProductCategory productCategory, Integer uomId, Date created, Integer createdBy) {
        this.productId = productId;
        this.name = name;
        this.productCategory = productCategory;
        this.created = created;
        this.createdBy = createdBy;
    }

    public Product(String name, ProductCategory productCategory) {
        this.name = name;
        this.productCategory = productCategory;
    }

    public Integer getProductId() {
        return productId;
    }

    public void setProductId(Integer productId) {
        this.productId = productId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getProductCategoryId() {
        return productCategoryId;
    }

    public void setProductCategoryId(Integer productCategoryId) {
        this.productCategoryId = productCategoryId;
    }

//  public ProductCategory getProductCategory() {
//      return productCategory;
//  }
//
//  public void setProductCategory(ProductCategory productCategory) {
//      this.productCategory = productCategory;
//  }

    public Date getCreated() {
        return created;
    }

    public void setCreated(Date created) {
        this.created = created;
    }

    public Integer getCreatedBy() {
        return createdBy;
    }

    public void setCreatedBy(Integer createdBy) {
        this.createdBy = createdBy;
    }
}

产品类别.java:

    @Entity
    public class ProductCategory {

    @Id
    private Integer productCategoryId;
    private String name;
    private Date created;
    private Integer createdBy;

    public ProductCategory() {
    }

    public ProductCategory(Integer productCategoryId, String name, Date created, Integer createdBy) {
        this.productCategoryId = productCategoryId;
        this.name = name;
        this.created = created;
        this.createdBy = createdBy;
    }

    public Integer getProductCategoryId() {
        return productCategoryId;
    }

    public void setProductCategoryId(Integer productCategoryId) {
        this.productCategoryId = productCategoryId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Date getCreated() {
        return created;
    }

    public void setCreated(Date created) {
        this.created = created;
    }

    public Integer getCreatedBy() {
        return createdBy;
    }

    public void setCreatedBy(Integer createdBy) {
        this.createdBy = createdBy;
    }
}

ProductServiceImpl.java

@Service
@Transactional
public class ProductServiceImpl implements ProductService {



 @Autowired
     private ProductRepository productRepository;

    public Product findOne(int productId) {
        return productRepository.findOne(productId);
    }

    public List<Product> findAll() {
        List<Product> products = new ArrayList<>();
        productRepository.findAll().forEach(products::add);
        return products;
    }

    @Override
    public List<Product> findBatch(int start, int end) {
        return productRepository.findBatch(start, end);
    }
}

ProductController.java:

@RestController
@RequestMapping("/products")
@EnableTransactionManagement
public class ProductController {

    @Autowired
    private ProductService productService;

    @RequestMapping(method = RequestMethod.GET)
    public List<Product> findAll() {
        List<Product> products = productService.findAll();
        return products;
    }

    @RequestMapping(value = "/{productId}", method = RequestMethod.GET)
    public Product findOne(@PathVariable int productId) {
        Product product = productService.findOne(productId);
        return product;
    }

    @RequestMapping(value = "/{start}/{end}", method = RequestMethod.GET)
    public List<Product> findBatch(@PathVariable int start, @PathVariable int end) {
        List<Product> list = productService.findBatch(start, end);
        return list;
    }
}

ApplicationContextConfig.java:

public class ApplicationContextConfig {

    @Bean
    public HibernateJpaSessionFactoryBean sessionFactory(EntityManagerFactory emf) {
        HibernateJpaSessionFactoryBean factory = new HibernateJpaSessionFactoryBean();
        factory.setEntityManagerFactory(emf);
        return factory;
    }
}

响应还应包含完整注入(inject)的 ProductCategory 对象，但事实并非如此。

Answer 1

最后，解决方案是将其添加到我的 application.properties 文件中:

spring.jpa.hibernate.ddl-auto=validate
spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

第一行检查列是否存在而不更改其结构，而第二行更改 Hibernate 验证的默认命名策略并避免在表名称中添加下划线。