mysql - 如何在JPA中的db中保存对象后获取id？

Question

我在保存 claimDetail 对象后获取 id 时遇到问题，然后获取该保存对象的 id 它即将到来 0 。其实我想得到那个保存的对象 Id 。但它不会来。我没有使用 JPA。我已经创建了一个用于调度的 Spring Boot 应用程序。

这是我的 ClaimDetails.java 实体类:

@Entity
@Table(name = "claimtrans")
public class ClaimTrans {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
}

    claimDetail.setActive(1);
    claimDetail.setVersion(new Long(1));
    claimDetail.setCreatedBy(new Long(1));
    claimDetail.setCreatedDate(new Date());
    claimDetailService.saveClaimDetail(claimDetail);

int temp =claimDetail.getID()

温度为 0；

这是我的 JpaRepositoryFactory.java:

@Service
public class ClaimDetailService {

    private JpaRepositoryFactory jpaRepositoryFactory;

    @Autowired
    public ClaimDetailService(JpaRepositoryFactory jpaRepositoryFactory) {
        this.jpaRepositoryFactory = jpaRepositoryFactory;
    }

    @Transactional
    public void saveClaimDetail(ClaimDetail claimDetail) {
        JpaRepository<ClaimDetail, Long> mailAuditLogLongJpaRepository = jpaRepositoryFactory.getRepository(ClaimDetail.class);
        mailAuditLogLongJpaRepository.save(claimDetail);
    }

    public List<ClaimDetail> getAllClaimDetail() {
        JpaRepository<ClaimDetail, Long> mailAuditLogLongJpaRepository = jpaRepositoryFactory.getRepository(ClaimDetail.class);
        return mailAuditLogLongJpaRepository.findAll();
    }
}

这是我的 JPA 工厂。

@Component
public class JpaRepositoryFactory {

    @PersistenceContext
    private EntityManager entityManager;

    public <T> T getRepository(Class clazz) {
        notNull(clazz);
        notNull(entityManager);
        T crudRepository = (T) new SimpleJpaRepository(clazz, entityManager);
        return crudRepository;
    }
}   

pom.xml

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.5.RELEASE</version>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <start-class>org.sam.application.Application</start-class>
        <java.version>1.6</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.10</version>
        </dependency>

任何人都可以帮助我请如何解决这个问题？

谢谢
西坦苏

Answer 1

JPA 规范不保证提供的实体对象在保存后会更新。要获取保存的 JPA 实体，您必须使用 save() 的返回值。方法。例如，您的服务可以这样更改:

@Service
public class ClaimDetailService {
    ...
    @Transactional
    public ClaimDetail saveClaimDetail(ClaimDetail claimDetail) {
        JpaRepository<ClaimDetail, Long> mailAuditLogLongJpaRepository = jpaRepositoryFactory.getRepository(ClaimDetail.class);
        return mailAuditLogLongJpaRepository.save(claimDetail);
    }
    ...
}

您的示例代码将是:

claimDetail.setActive(1);
claimDetail.setVersion(new Long(1));
claimDetail.setCreatedBy(new Long(1));
claimDetail.setCreatedDate(new Date());
ClaimDetail savedClaimDetail = claimDetailService.saveClaimDetail(claimDetail);
int temp = savedClaimDetail.getID()

此外，虽然与您的问题没有直接关系，但您不需要按照您的方式创建 Spring Data 存储库。只需创建您自己的接口(interface)扩展 JPARepository。