[英]Jackson and Hibernate exception with mapping
我在Hibernate-Spring MVC中遇到几个问题。 这是我从控制器到数据库实体的调用的一个示例:
控制者
@Override
@RequestMapping(value = { "/cars/{idFleet}"}, method = RequestMethod.GET)
public @ResponseBody Response<List<Car>> getCars(@PathVariable int idFleet) throws QueryException{
return fleetAndCarService.findCarsByIdFleet(idFleet);
}
服务
@Override
// @Transactional
public Response<List<Car>> findCarsByIdFleet(int idFleet) throws QueryException {
try{
return new Response<List<Car>>(HttpStatus.OK.value(),databaseFleetsAndCarsServices.findCarsByIdFleet(idFleet));
} catch (Exception e) {
throw new QueryException(e);
}
}
数据库服务
@Override
public List<Car> findCarsByIdFleet(int idFleet) {
return carServices.findByFleetIdFleet(idFleet);
}
具有命名查询的汽车服务
@Override
@Transactional
public List<Car> findByFleetIdFleet(int idFleet) {
return carRepository.findByFleetIdFleet(idFleet);
}
汽车资料库
public interface CarRepository extends JpaRepository<Car, Integer> {
//Query method of spring, I put findBy and then the key of research
List<Car> findByFleetIdFleet(int idFleet);
}
汽车实体
@Entity
@Table(name =“ car”,catalog =“ ATS”)公共类Car实现java.io.Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private Integer idCar;
private CarType carType;
private Fleet fleet;
private String id;
private int initialKm;
private String carChassis;
private String note;
private Set<Acquisition> acquisitions = new HashSet<Acquisition>(0);
public Car() {
}
public Car(CarType carType, Fleet fleet, int initialKm, String carChassis) {
this.carType = carType;
this.fleet = fleet;
this.initialKm = initialKm;
this.carChassis = carChassis;
}
public Car(CarType carType, Fleet fleet, String id, int initialKm, String carChassis, String note,
Set<Acquisition> acquisitions) {
this.carType = carType;
this.fleet = fleet;
this.id = id;
this.initialKm = initialKm;
this.carChassis = carChassis;
this.note = note;
this.acquisitions = acquisitions;
}
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id_car", unique = true, nullable = false)
public Integer getIdCar() {
return this.idCar;
}
public void setIdCar(Integer idCar) {
this.idCar = idCar;
}
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "id_carType", nullable = false)
public CarType getCarType() {
return this.carType;
}
public void setCarType(CarType carType) {
this.carType = carType;
}
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "id_fleet", nullable = false)
public Fleet getFleet() {
return this.fleet;
}
public void setFleet(Fleet fleet) {
this.fleet = fleet;
}
@Column(name = "id", length = 5)
public String getId() {
return this.id;
}
public void setId(String id) {
this.id = id;
}
@Column(name = "initialKm", nullable = false)
public int getInitialKm() {
return this.initialKm;
}
public void setInitialKm(int initialKm) {
this.initialKm = initialKm;
}
@Column(name = "carChassis", nullable = false, length = 20)
public String getCarChassis() {
return this.carChassis;
}
public void setCarChassis(String carChassis) {
this.carChassis = carChassis;
}
@Column(name = "note", length = 100)
public String getNote() {
return this.note;
}
public void setNote(String note) {
this.note = note;
}
@OneToMany(fetch = FetchType.LAZY, mappedBy = "car")
public Set<Acquisition> getAcquisitions() {
return this.acquisitions;
}
public void setAcquisitions(Set<Acquisition> acquisitions) {
this.acquisitions = acquisitions;
}
}
汽车类型(通过外键链接,一对多关系)
/**
* CarType generated by hbm2java
*/
@Entity
@Table(name = "carType", catalog = "ATS")
public class CarType implements java.io.Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private String idCarType;
private String note;
private Set<Car> cars = new HashSet<Car>(0);
public CarType() {
}
public CarType(String idCarType) {
this.idCarType = idCarType;
}
public CarType(String idCarType, String note, Set<Car> cars) {
this.idCarType = idCarType;
this.note = note;
this.cars = cars;
}
@Id
@Column(name = "id_carType", unique = true, nullable = false, length = 5)
public String getIdCarType() {
return this.idCarType;
}
public void setIdCarType(String idCarType) {
this.idCarType = idCarType;
}
@Column(name = "note", length = 100)
public String getNote() {
return this.note;
}
public void setNote(String note) {
this.note = note;
}
@OneToMany(fetch = FetchType.LAZY, mappedBy = "carType")
public Set<Car> getCars() {
return this.cars;
}
public void setCars(Set<Car> cars) {
this.cars = cars;
}
}
舰队实体
@Entity
@Table(name = "fleet", catalog = "ATS")
public class Fleet implements java.io.Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private Integer idFleet;
private Ecu ecu;
private String application;
private String cubic;
private int power;
private String euroClass;
private String engineType;
private String traction;
private String transmission;
private String note;
private Set<Car> cars = new HashSet<Car>(0);
收购实体
@Entity
@Table(name = "acquisition", catalog = "ATS")
public class Acquisition implements java.io.Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private Integer idAcquisition;
private Car car;
private DpfWeighting dpfWeighting;
private MissionProfile missionProfile;
private OilSample oilSample;
private Shift shift;
private SwVersion swVersion;
private Date date;
private float sessionDuration;
private int beginKm;
private int endKm;
private String driverName;
private String dataset;
private String drChannelsConf;
private String excelRow;
private Set<Rdi> rdis = new HashSet<Rdi>(0);
private Set<SelfLearning> selfLearnings = new HashSet<SelfLearning>(0);
private Set<Iupr> iuprs = new HashSet<Iupr>(0);
我正在将Maven与4.2.1.RELEASE 4.3.11.Final一起使用
当我打电话给控制器时,我收到一个异常:
com.fasterxml.jackson.databind.JsonMappingException:未找到类org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer的序列化器,也未发现创建BeanSerializer的属性(为避免异常,请禁用SerializationFeature.FAIL_ON_EMPTY_BEANS))(通过引用链: .model.Response [“ body”]-> java.util.ArrayList [0]-> com.domain.Car [“ carType”]-> com.domain.CarType _ $$ _ jvst615_e [“ handler”])
我想了解是否必须从实体中删除设置变量,以及如何解决映射上的异常。 谢谢目前我在每个实体上使用@JsonIgnoreProperties({“ hibernateLazyInitializer”,“ handler”}),但这是正确的?还是我选择了错误的方式来生成实体?)
当我使用类似的存储库方法时
@Override
@Transactional
public List<Fleet> getFleets() {
return fleetRepository.findAll();
}
没问题,效果很好
更新 :我添加@JsonManagedReference
上@OneToMany
变量和@JsonBackReference
上@ManyToOne
变量,它似乎工作,但现在在车上我只能看到收购,而不是舰队和CarType(所以没有标注与JsonBackReference),而不是从我的查询接收所有该对象,但carType和Fleet为空,我需要相反,所以我需要Fleet和carType,而不是获取这是我在杰克逊JSON和Hibernate JPA问题中发现它的Infinite Recursion的链接
试加@ManyToOne(fetch = FetchType.EAGER)
到您的Car
实体-属性carType
(或方法getCarType
-取决于你用什么)。 对于EAGER提取- Car
实体应具有实体对象而非代理对象。
从应用程序返回实体不是一个好习惯,因为您无法控制将返回什么关系和数据。 而不是您应该返回VO(值对象)。 使用VO是安全的,您可以控制从应用程序返回的内容。 从entites的到VO对象(包括关系),你可以使用一些映射器,mappigs Orika例如。
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