添加新的关联JPA实体将尝试插入具有空id的行

Question

我有2个类似于以下内容的JPA实体：

@Entity
class Customer {
   @Id
   @GeneratedValue
   Long id

   @OneToOne(cascade = CascadeType.ALL)
   @PrimaryKeyJoinColumn
   CustomerInformation customerInformation
}


@Entity
class CustomerInformation {
   @Id
   @OneToOne
   @JoinColumn(name = "id")
   Customer customer

   String firstName
   String lastName
}

我正在使用spring-data-jpa生成我的DAO层。虽然不是很有趣，但它是这样的：

public interface CustomerRepository extends CrudRepository<Customer, Long> {
}

@Transactional
public void createNewCustomer() {
   Customer cust = new Customer();
   CustomerInformation custInf = new CustomerInformation;
   custInf.setCustomer(cust);
   custInf.setFirstName("asdf");
   custInf.setLastName("hjkl");

   cust.setCustomerInformation(custInf);

   customerRepository.save(cust);
}

@Transactional
public void updateExistingCustomer(Long userId) {

   Customer foundCustomer = customerRepository.findOne(userId);

   if (foundCustomer.getCustomerInformation() == null) {
      CustomerInformation custInf = new CustomerInformation();
      custInf.setCustomer(foundCustomer);
      custInf.setFirstName("asdf");
      custInf.setLastName("hjkl");

      cust.setCustomerInformation(custInf);

      customerRepository.save(foundCustomer);
   }
}

Hibernate: insert into CustomerInformation (firstName, lastName, id) values (?, ?, ?)
Feb 1, 2013 7:40:12 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 20000, SQLState: 23502
Feb 1, 2013 7:40:12 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: Column 'ID'  cannot accept a NULL value.

Answer 1

您还应该将id字段标记为生成的值，因此hibernate将为其提供一些值：

@Entity
class Customer {
   @Id
   @GeneratedValue // !!!
   Long id

...

@Entity
class CustomerInformation {
   @Id
   @GeneratedValue // !!!
   @OneToOne
   @JoinColumn(name = "id")
   Customer customer

...