I have faced with the problem that converter can't handle JSON object.
I have two objects in data base. Relationship OneToMany.
I have a AutoService with many services.
And wnen i am trying to send JSON object using postman to my server - I am getting an error:
WARN org.springframework.http.converter.json.MappingJackson2HttpMessageConverter - Failed to evaluate Jackson deserialization for type [[simple type, class com.webserverconfig.user.entity.AutoService]]: java.lang.IllegalArgumentException: Can not handle managed/back reference 'defaultReference': no back reference property found from type [collection type; class java.util.List, contains [simple type, class com.webserverconfig.user.entity.Service]]
Next two classes represents my model:
Class AutoService:
@Entity
@Table(name = "AutoRate")
public class AutoService {
public AutoService() {
}
@Id
@GeneratedValue(generator = "increment")
@GenericGenerator(name = "increment", strategy = "increment")
private long id;
@Column(name = "serviceName", nullable = false)
private String serviceName;
@Column(name = "imageURL", nullable = false)
private String imageURL;
@Column(name = "mapCoordinate", nullable = false)
private String mapCoordinate;
@Column(name = "websiteURL", nullable = false)
private String websiteURL;
@Column(name = "phoneNumber", nullable = false)
private String phoneNumber;
@JsonManagedReference
@OneToMany(fetch = FetchType.EAGER)
@JoinColumn(name = "autoServiceId")
private List<Service> services;
public long getId() {
return id;
}
public String getServiceName() {
return serviceName;
}
public String getImageURL() {
return imageURL;
}
public String getMapCoordinate() {
return mapCoordinate;
}
public String getWebsiteURL() {
return websiteURL;
}
public String getPhoneNumber() {
return phoneNumber;
}
public List<Service> getServices() {
return services;
}
}
Class service:
@Entity
@Table(name = "Service")
public class Service {
public Service() {
}
@Id
@GeneratedValue(generator = "increment")
@GenericGenerator(name = "increment", strategy = "increment")
@Column(name = "serviceId", unique = true, nullable = false)
private long serviceId;
@Column(name = "serviceName", nullable = false)
private String serviceName;
@Column(name = "category", nullable = false)
private String category;
@Column(name = "price", nullable = false)
private int price;
@Column(name = "autoServiceId", nullable = false)
private long autoServiceId;
public long getId() {
return serviceId;
}
public String getCategory() {
return category;
}
public int getPrice() {
return price;
}
public String getServiceName() {
return serviceName;
}
public long getAutoServiceId() {
return autoServiceId;
}
}
Asking for help. Am i missing some annotation ?
Also Controller class:
@RestController
@RequestMapping("/directory")
public class ServiceController {
@Autowired
private AutoRateService dataBaseService;
@RequestMapping(value = "/get", method = RequestMethod.GET)
@ResponseBody
public AutoService getData(){
AutoService dataList = dataBaseService.getById(1);
return dataList;
}
@RequestMapping(value = "/saveService", method = RequestMethod.POST)
@ResponseBody public AutoService saveAutoService(@RequestBody AutoService autoService){
return dataBaseService.save(autoService);
}
}
You could add @JsonBackReference
to the other site of the relation. Which by the way is missing or not correct implemented. Add:
@JsonBackReference
@ManyToOne
@JoinColumn(name = "autoServiceId", nullable = false)
private AutoService autoService;
instead of private long autoServiceId;
.
Also the AutoService needs to be adjusted with:
@JsonManagedReference
@OneToMany(mappedBy = "autoService", fetch=FetchType.EAGER)
private List<Service> services = new ArrayList<>();
Solution #1 : - add @JsonIgnore where you have attributes with @OneToMany Example:
class User {
@OneToMany(mappedBy = "user", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JsonManagedReference
@JsonIgnore
private List<Comment> comments;
}
class Comment {
@ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinColumn(name = "user_id")
@JsonBackReference
private User user;
}
Solution #2: - use on your class @JsonIgnoreProperties({"name-of-your-attribute"}), for example "comments"
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.