我有一个 StudentAdmissinAssoDTO 这个有其他课程参考的课程
如下
StudentAdmissinAssoDTO
package com.rasvek.cg.entity;
import java.util.List;
import com.fasterxml.jackson.annotation.JsonBackReference;
public class StudentAdmissinAssoDTO
{
private PrimaryStudentAdmission primaryAdmission;
private StudentDetails studentDetailsDto;
private StudentJoiningDetails studentJoiningDetails;
private StudentPresentClassDetails studentPresentClassDetails;
private StudentGeneralDetails studentGeneralDetails;
private StudentPrevSchoolDetails studentPrevSchoolDetails;
private StudentParentDetails studentParentDetails;
private MasterAddress masterAddress;
private List<AssocFeeStudent> assocFeeStudentId;
public StudentDetails getStudentDetailsDto() {
return studentDetailsDto;
}
public void ListStudentDetailsDto(StudentDetails studentDetailsDto) {
this.studentDetailsDto = studentDetailsDto;
}
public PrimaryStudentAdmission getPrimaryAdmission() {
return primaryAdmission;
}
public void ListPrimaryAdmission(PrimaryStudentAdmission primaryAdmission) {
this.primaryAdmission = primaryAdmission;
}
public StudentJoiningDetails getStudentJoiningDetails() {
return studentJoiningDetails;
}
public void ListStudentJoiningDetails(StudentJoiningDetails studentJoiningDetails) {
this.studentJoiningDetails = studentJoiningDetails;
}
public StudentPresentClassDetails getStudentPresentClassDetails() {
return studentPresentClassDetails;
}
public void ListStudentPresentClassDetails(StudentPresentClassDetails studentPresentClassDetails) {
this.studentPresentClassDetails = studentPresentClassDetails;
}
public StudentGeneralDetails getStudentGeneralDetails() {
return studentGeneralDetails;
}
public void ListStudentGeneralDetails(StudentGeneralDetails studentGeneralDetails) {
this.studentGeneralDetails = studentGeneralDetails;
}
public StudentPrevSchoolDetails getStudentPrevSchoolDetails() {
return studentPrevSchoolDetails;
}
public void ListStudentPrevSchoolDetails(StudentPrevSchoolDetails studentPrevSchoolDetails) {
this.studentPrevSchoolDetails = studentPrevSchoolDetails;
}
public StudentParentDetails getStudentParentDetails() {
return studentParentDetails;
}
public void ListStudentParentDetails(StudentParentDetails studentParentDetails) {
this.studentParentDetails = studentParentDetails;
}
public MasterAddress getMasterAddress() {
return masterAddress;
}
public void ListMasterAddress(MasterAddress masterAddress) {
this.masterAddress = masterAddress;
}
public List<AssocFeeStudent> getAssocFeeStudentId() {
return assocFeeStudentId;
}
public void ListAssocFeeStudentId(List<AssocFeeStudent> assocFeeStudentId) {
this.assocFeeStudentId = assocFeeStudentId;
}
}
我得到了这个例外
（HTTP-NIO-8017-EXEC-3：org.springframework.http.converter.json.MappingJackson2HttpMessageConverter）：
[org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.logWarningIfNecessary(AbstractJackson2HttpMessageConverter.java:205)]
Failed to evaluate Jackson deserialization for type [[simple type, class com.rasvek.cg.entity.StudentAdmissinAssoDTO]]: java.lang.IllegalArgumentException: Can not handle managed/back reference 'defaultReference': no back reference property found from type [collection type; class java.util.Set, contains [simple type, class com.rasvek.cg.entity.MasterAddress]]
请查看 MasterAddress
package com.rasvek.cg.entity;
//Generated May 14, 2018 11:39:07 PM by Hibernate Tools 5.1.7.Final
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Transient;
import com.fasterxml.jackson.annotation.JsonBackReference;
import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.JsonManagedReference;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;
/**
* MasterAddress generated by hbm2java
*/
@Entity
@Table(name = "master_address", catalog = "campus_guru_01")
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class,property = "addressId")
public class MasterAddress implements java.io.Serializable {
private Integer addressId;
private Integer studentAdmissionId;
private String isSame;
private MasterAddressCountry masterAddressCountry;
private MasterAddressDistrict masterAddressDistrict;
private MasterAddressState masterAddressState;
private String houseNum;
private String streetAddress;
private String citymandal;
private String pincode;
private String addressType;
private Set<AssocStaffAddress> assocStaffAddresses = new HashSet<AssocStaffAddress>(0);
private Set<AssocStudentAddress> assocStudentAddresses = new HashSet<AssocStudentAddress>(0);
public MasterAddress() {
}
public MasterAddress(MasterAddressCountry masterAddressCountry, MasterAddressDistrict masterAddressDistrict,
MasterAddressState masterAddressState) {
this.masterAddressCountry = masterAddressCountry;
this.masterAddressDistrict = masterAddressDistrict;
this.masterAddressState = masterAddressState;
}
public MasterAddress(MasterAddressCountry masterAddressCountry, MasterAddressDistrict masterAddressDistrict, MasterAddressState masterAddressState, String houseNum, String streetAddress, String citymandal, String pincode, String addressType, Set<AssocStaffAddress> assocStaffAddresses, Set<AssocStudentAddress> assocStudentAddresses) {
this.masterAddressCountry = masterAddressCountry;
this.masterAddressDistrict = masterAddressDistrict;
this.masterAddressState = masterAddressState;
this.houseNum = houseNum;
this.streetAddress = streetAddress;
this.citymandal = citymandal;
this.pincode = pincode;
this.addressType = addressType;
this.assocStaffAddresses = assocStaffAddresses;
this.assocStudentAddresses = assocStudentAddresses;
}
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "address_id", unique = true, nullable = false)
public Integer getAddressId() {
return this.addressId;
}
public void setAddressId(Integer addressId) {
this.addressId = addressId;
}
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "country_id", nullable = false)
public MasterAddressCountry getMasterAddressCountry() {
return this.masterAddressCountry;
}
public void setMasterAddressCountry(MasterAddressCountry masterAddressCountry) {
this.masterAddressCountry = masterAddressCountry;
}
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "district_id", nullable = false)
public MasterAddressDistrict getMasterAddressDistrict() {
return this.masterAddressDistrict;
}
public void setMasterAddressDistrict(MasterAddressDistrict masterAddressDistrict) {
this.masterAddressDistrict = masterAddressDistrict;
}
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "state_id", nullable = false)
public MasterAddressState getMasterAddressState() {
return this.masterAddressState;
}
public void setMasterAddressState(MasterAddressState masterAddressState) {
this.masterAddressState = masterAddressState;
}
@Column(name = "house_num", length = 45)
public String getHouseNum() {
return this.houseNum;
}
public void setHouseNum(String houseNum) {
this.houseNum = houseNum;
}
@Column(name = "street_address", length = 45)
public String getStreetAddress() {
return this.streetAddress;
}
public void setStreetAddress(String streetAddress) {
this.streetAddress = streetAddress;
}
@Column(name="citymandal")
public String getCitymandal() {
return this.citymandal;
}
public void setCitymandal(String citymandal) {
this.citymandal = citymandal;
}
@Column(name = "pincode", length = 45)
public String getPincode() {
return this.pincode;
}
public void setPincode(String pincode) {
this.pincode = pincode;
}
@Column(name = "address_type", length = 9)
public String getAddressType() {
return this.addressType;
}
public void setAddressType(String addressType) {
this.addressType = addressType;
}
@OneToMany(fetch = FetchType.EAGER, mappedBy = "masterAddress")
public Set<AssocStaffAddress> getAssocStaffAddresses() {
return this.assocStaffAddresses;
}
public void setAssocStaffAddresses(Set<AssocStaffAddress> assocStaffAddresses) {
this.assocStaffAddresses = assocStaffAddresses;
}
@OneToMany(fetch = FetchType.EAGER, mappedBy = "masterAddress")
public Set<AssocStudentAddress> getAssocStudentAddresses() {
return this.assocStudentAddresses;
}
public void setAssocStudentAddresses(Set<AssocStudentAddress> assocStudentAddresses) {
this.assocStudentAddresses = assocStudentAddresses;
}
@Column(name="student_admission_id")
public Integer getStudentAdmissionId() {
return studentAdmissionId;
}
public void setStudentAdmissionId(Integer studentAdmissionId) {
this.studentAdmissionId = studentAdmissionId;
}
@Column(name="is_same")
public String getIsSame() {
return isSame;
}
public void setIsSame(String isSame) {
this.isSame = isSame;
}
}
StudentAdmissinAssoDTO 和 MasterAddress 之间没有依赖关系依赖关系。
我只是使用StudentAdmissinAssoDTO来制作嵌套的json对象。
这样我就可以在controller
MasterAddress masterAddress =null;
masterAddress = studentAdmissinAssoDTO.getMasterAddress();
为什么我得到这个例外
(http-nio-8017-exec-3:org.springframework.http.converter.json.MappingJackson2HttpMessageConverter): [org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.logWarningIfNecessary(AbstractJackson2HttpMessageConverter.java:205)]
Failed to evaluate Jackson deserialization for type [[simple type, class com.rasvek.cg.entity.StudentAdmissinAssoDTO]]: java.lang.IllegalArgumentException: Can not handle managed/back reference 'defaultReference': no back reference property found from type [collection type; class java.util.Set, contains [simple type, class com.rasvek.cg.entity.MasterAddress]
任何人都可以解释为什么会这样发生。谢谢！。
答案 0 :(得分：0)
我发现我的错误是我在@JsonManagedReference的MasterDistrict类中错位MasterAddress