[英]Jackson and Hibernate exception with mapping
我在Hibernate-Spring MVC中遇到幾個問題。 這是我從控制器到數據庫實體的調用的一個示例:
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);
}
服務
@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);
}
}
數據庫服務
@Override
public List<Car> findCarsByIdFleet(int idFleet) {
return carServices.findByFleetIdFleet(idFleet);
}
具有命名查詢的汽車服務
@Override
@Transactional
public List<Car> findByFleetIdFleet(int idFleet) {
return carRepository.findByFleetIdFleet(idFleet);
}
汽車資料庫
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);
}
汽車實體
@Entity
@Table(name =“ car”,catalog =“ ATS”)公共類Car實現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;
}
}
汽車類型(通過外鍵鏈接,一對多關系)
/**
* 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;
}
}
艦隊實體
@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);
收購實體
@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);
我正在將Maven與4.2.1.RELEASE 4.3.11.Final一起使用
當我打電話給控制器時,我收到一個異常:
com.fasterxml.jackson.databind.JsonMappingException:未找到類org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer的序列化器,也未發現創建BeanSerializer的屬性(為避免異常,請禁用SerializationFeature.FAIL_ON_EMPTY_BEANS))(通過引用鏈: .model.Response [“ body”]-> java.util.ArrayList [0]-> com.domain.Car [“ carType”]-> com.domain.CarType _ $$ _ jvst615_e [“ handler”])
我想了解是否必須從實體中刪除設置變量,以及如何解決映射上的異常。 謝謝目前我在每個實體上使用@JsonIgnoreProperties({“ hibernateLazyInitializer”,“ handler”}),但這是正確的?還是我選擇了錯誤的方式來生成實體?)
當我使用類似的存儲庫方法時
@Override
@Transactional
public List<Fleet> getFleets() {
return fleetRepository.findAll();
}
沒問題,效果很好
更新 :我添加@JsonManagedReference
上@OneToMany
變量和@JsonBackReference
上@ManyToOne
變量,它似乎工作,但現在在車上我只能看到收購,而不是艦隊和CarType(所以沒有標注與JsonBackReference),而不是從我的查詢接收所有該對象,但carType和Fleet為空,我需要相反,所以我需要Fleet和carType,而不是獲取這是我在傑克遜JSON和Hibernate JPA問題中發現它的Infinite Recursion的鏈接
試加@ManyToOne(fetch = FetchType.EAGER)
到您的Car
實體-屬性carType
(或方法getCarType
-取決於你用什么)。 對於EAGER提取- Car
實體應具有實體對象而非代理對象。
從應用程序返回實體不是一個好習慣,因為您無法控制將返回什么關系和數據。 而不是您應該返回VO(值對象)。 使用VO是安全的,您可以控制從應用程序返回的內容。 從entites的到VO對象(包括關系),你可以使用一些映射器,mappigs Orika例如。
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