hibernate - 无法在 Spring Boot REST 中从 Hibernate POJO 返回 JSON

Question

我正在尝试使用 Spring Boot 创建一个基本的 REST 服务，该服务返回使用 Hibernate 从数据库创建的 POJO，然后转换为 JSON 并返回给 REST 调用。

我可以让常规的非 Hibernate POJO 作为 JSON 返回，但是对于 Hibernate 对象我收到这个错误:

Failed to write HTTP message: org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS); nested exception is com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.example.springboottest.model.Person_$$_jvst48e_0["handler"])

这是我的代码:

Person.java

@Entity
@Table(name = "people")
public class Person implements Serializable {

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

private String nameLast;
private String nameFirst;

@Temporal(TemporalType.DATE)
private Date dob;

protected Person(){}

public Person(String nameLast, String nameFirst, Date dob) {
    this.nameLast = nameLast;
    this.nameFirst = nameFirst;
    this.dob = dob;
}

// Getters and Setters...

PersonRepository.java

@Repository
public interface PersonRepository extends JpaRepository<Person, Long>{

}

PersonController.java

@RestController
public class PersonController {

    @Autowired
    PersonRepository personRepository;

    @GetMapping("/person/{id:\\d+}")
    public Person getPersonByID(@PathVariable long id){
        return personRepository.getOne(id);
    }
}

如果有人能帮助我理解为什么这不起作用，我将不胜感激。谢谢!

Answer 1

原来这都是我用错方法造成的。如果我将 return personRepository.getOne(id) 替换为 return personRepository.findOne(id)，则效果很好。我不明白为什么 getOne() 不起作用，但这确实解决了问题。