java - 为什么我的 JPA Repository Impl 代码没有被调用？

Question

我有以下简单的 Spring Boot 代码。为什么我的 JPARepositoryImpl 代码 - JpaCustomerRepository 没有被调用(我通过添加 print 语句知道..)？

我在主 Controller 和 Controller 中添加了@ComponentScan。请指教。

谢谢

    @Entity
    public class Customer implements Serializable {

        private static final long serialVersionUID = 1L;

        @Id
        @GeneratedValue
        private Long id;

        @Column(nullable = false)
        private String product;

        @Column(nullable = false)
        private String charge;

        protected Customer() {
        }

        public Customer(String product) {
            this.product = product;
        }

        public Long getId() {
            return id;
        }

        public String getProduct() {
            return this.product;
        }


        public String getCharge() {
            return this.charge;
        }}


    public interface CustomerRepository extends Repository<Customer, Long> {

            List<Customer> findAll();

        }

        @Repository
        class JpaCustomerRepository implements CustomerRepository {

            @PersistenceContext
            private EntityManager em;

            @Override
            public List<Customer> findAll() {
                TypedQuery<Customer> query = em.createQuery("select c from Customer c",
                        Customer.class);

                return query.getResultList();
            }


        }

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class SampleDataJpaApplication {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SampleDataJpaApplication.class, args);
    }

}
@Controller
@ComponentScan
@RequestMapping("/customers")
public class SampleController {
    private CustomerRepository customerRepository;

    @Autowired
    public SampleController(CustomerRepository customerRepository) {
        this.customerRepository = customerRepository;
    }

    @RequestMapping("/list")
    public String list(Model model) {
        model.addAttribute("customers", this.customerRepository.findAll());
        return "customers/list";
    }


}

但是 Spring Data 书中的示例代码 (JpaCustomerRepository) 确实被调用了。有什么问题吗？

@MappedSuperclass
public class AbstractEntity {

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

    /**
     * Returns the identifier of the entity.
     * 
     * @return the id
     */
    public Long getId() {
        return id;
    }

    /* 
     * (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {

        if (this == obj) {
            return true;
        }

        if (this.id == null || obj == null || !(this.getClass().equals(obj.getClass()))) {
            return false;
        }

        AbstractEntity that = (AbstractEntity) obj;

        return this.id.equals(that.getId());
    }

    /* 
     * (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        return id == null ? 0 : id.hashCode();
    }
}
    @Entity
    public class Customer extends AbstractEntity {

        private String firstname, lastname;

        @Column(unique = true)
        private EmailAddress emailAddress;

        @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
        @JoinColumn(name = "customer_id")
        private Set<Address> addresses = new HashSet<Address>();

        /**
         * Creates a new {@link Customer} from the given firstname and lastname.
         * 
         * @param firstname must not be {@literal null} or empty.
         * @param lastname must not be {@literal null} or empty.
         */
        public Customer(String firstname, String lastname) {

            Assert.hasText(firstname);
            Assert.hasText(lastname);

            this.firstname = firstname;
            this.lastname = lastname;
        }

        protected Customer() {

        }

        /**
         * Adds the given {@link Address} to the {@link Customer}.
         * 
         * @param address must not be {@literal null}.
         */
        public void add(Address address) {

            Assert.notNull(address);
            this.addresses.add(address);
        }

        /**
         * Returns the firstname of the {@link Customer}.
         * 
         * @return
         */
        public String getFirstname() {
            return firstname;
        }

        /**
         * Returns the lastname of the {@link Customer}.
         * 
         * @return
         */
        public String getLastname() {
            return lastname;
        }

        /**
         * Sets the lastname of the {@link Customer}.
         * 
         * @param lastname
         */
        public void setLastname(String lastname) {
            this.lastname = lastname;
        }

        /**
         * Returns the {@link EmailAddress} of the {@link Customer}.
         * 
         * @return
         */
        public EmailAddress getEmailAddress() {
            return emailAddress;
        }

        /**
         * Sets the {@link Customer}'s {@link EmailAddress}.
         * 
         * @param emailAddress must not be {@literal null}.
         */
        public void setEmailAddress(EmailAddress emailAddress) {
            this.emailAddress = emailAddress;
        }

        /**
         * Return the {@link Customer}'s addresses.
         * 
         * @return
         */
        public Set<Address> getAddresses() {
            return Collections.unmodifiableSet(addresses);
        }
    }
    public interface CustomerRepository extends Repository<Customer, Long> {

        /**
         * Returns the {@link Customer} with the given identifier.
         * 
         * @param id the id to search for.
         * @return
         */
        Customer findOne(Long id);

        /**
         * Saves the given {@link Customer}.
         * 
         * @param customer the {@link Customer} to search for.
         * @return
         */
        Customer save(Customer customer);

        /**
         * Returns the customer with the given {@link EmailAddress}.
         * 
         * @param emailAddress the {@link EmailAddress} to search for.
         * @return
         */
        Customer findByEmailAddress(EmailAddress emailAddress);
    }
    @Repository
    class JpaCustomerRepository implements CustomerRepository {

        @PersistenceContext
        private EntityManager em;

        /* 
         * (non-Javadoc)
         * @see com.oreilly.springdata.jpa.core.CustomerRepository#findOne(java.lang.Long)
         */
        @Override
        public Customer findOne(Long id) {
            return em.find(Customer.class, id);
        }

        /*
         * (non-Javadoc)
         * @see com.oreilly.springdata.jpa.core.CustomerRepository#save(com.oreilly.springdata.jpa.core.Customer)
         */
        public Customer save(Customer customer) {
            if (customer.getId() == null) {
                em.persist(customer);
                return customer;
            } else {
                return em.merge(customer);
            }
        }

        /* 
         * (non-Javadoc)
         * @see com.oreilly.springdata.jpa.core.CustomerRepository#findByEmailAddress(com.oreilly.springdata.jpa.core.EmailAddress)
         */
        @Override
        public Customer findByEmailAddress(EmailAddress emailAddress) {
            TypedQuery<Customer> query = em.createQuery("select c from Customer c where c.emailAddress = :email",
                    Customer.class);
            query.setParameter("email", emailAddress);

            return query.getSingleResult();
        }
    }

原代码测试方法，

@ContextConfiguration(classes = PlainJpaConfig.class)
public class JpaCustomerRepositoryIntegrationTest extends AbstractIntegrationTest {

    @Autowired
    CustomerRepository repository;

    @Test
    public void insertsNewCustomerCorrectly() {

        Customer customer = new Customer("Alicia", "Keys");
        customer = repository.save(customer);

        assertThat(customer.getId(), is(notNullValue()));
    }

    @Test
    public void updatesCustomerCorrectly() {

        Customer dave = repository.findByFirstname("Dave");
        assertThat(dave, is(notNullValue()));

        dave.setLastname("Miller");
        dave = repository.save(dave);

        Customer reference = repository.findByFirstname(dave.getFirstname());
        assertThat(reference.getLastname(), is(dave.getLastname()));
    }
}

我的主要方法代码，

@Configuration
@ComponentScan
@EnableAutoConfiguration
@ContextConfiguration(classes = PlainJpaConfig.class)
public class SampleDataJpaApplication {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SampleDataJpaApplication.class, args);
    }

}

我有额外的@EnableAutoConfiguration，而原始代码没有？难道是这个原因吗？但是如果没有@EnableAutoConfiguration，我将无法启动Spring Boot Container。

Answer 1

您的代码不会被调用，因为 Spring Data 正在动态提供 CustomerRepository 的实现。您的代码是多余的(从某种意义上说，它没有执行 Spring Data 无法自动执行的操作)，但如果您想了解如何使用 Spring Data 无法自动生成的代码来增强 Spring Data 提供的实现，请查看documentation .