com.fasterxml.jackson.databind.JsonMappingException: 名称为'defaultReference'的多个反向引用属性

Question

当我试图将一个实体与多个实体进行映射时，我遇到了这个错误。

/// 这是我的候选人个人资料实体/////

    package com.demo.project.premiumjobportal.model;
import java.io.Serializable;
    import java.util.List;
import javax.persistence.CascadeType;
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.FetchType;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.ManyToOne;
    import javax.persistence.OneToMany;
    import javax.persistence.Table;
    import javax.validation.constraints.NotNull;
    import javax.xml.bind.annotation.XmlRootElement;
import com.fasterxml.jackson.annotation.JsonBackReference;
    import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
//候选人详细信息表：主表
    @Entity
    @Table(name="candidate_profile")
    @JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
    @XmlRootElement
    public class CandidateProfile implements Serializable {
 private static final long serialVersionUID = 1L;
@Id
        @GeneratedValue
        private int id;
@NotNull
        @Column(name="first_name", length = 25)
        private String firstName;
@NotNull
        @Column(name="last_name", length = 25)
        private String lastName;
@NotNull
        @Column(name="username", length = 50)
        private String username;
@Column(name="alt_email_id", length = 50)
        private String alternateEmailId;
@NotNull
        @Column(name="mobile_no", length = 15)
        private String mobileNum;
@Column(name="alt_mobile_no", length = 15)
        private String alternateMobileNum;
@Column(name="ssc_board", length = 50)
        private String sscBoard;
@Column(name="ssc_school", length = 50)
        private String sscSchool;
@Column(name="ssc_percent", length = 4)
        private float sscPercentage;
@Column(name="ssc_year_of_passout", length = 4)
        private int sscYearOfPassout;
@Column(name="hsc_board", length = 50)
        private String hscBoard;
@Column(name="hsc_school", length = 50)
        private String hscSchool;
@Column(name="hsc_percent", length = 4)
        private float hscPercentage;
@Column(name="hsc_year_of_passout", length = 4)
        private int hscYearOfPassout;
@Column(name="grad_university", length = 100)
        private String gradiduteUniversity;
@Column(name="grad_institute", length = 100)
        private String gradiduteInstitute;
@Column(name="grad_percent", length = 4)
        private float gradidutePercentage;
@Column(name="grad_year_of_passout", length = 4)
        private int gradiduteYearOfPassout;
@Column(name="postgrad_university", length = 100)
        private String postGradiduteUniversity;
@Column(name="postgrad_institute", length = 100)
        private String postGradiduteInstitute;
@Column(name="postgrad_percent", length = 4)
        private float postGradidutePercentage;
@Column(name="postgrad_year_of_passout", length = 4)
        private int postGradiduteYearOfPassout;
 private String notes;
 private String Password;
@OneToMany(mappedBy = "candidateProfile", fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
        @JsonBackReference
        private List experienceDetails;
@OneToMany(mappedBy = "candidateProfile", fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
        @JsonBackReference
        private List candidateJobs;
@ManyToOne
        private Role roleName;
/* 构造函数 */
        public CandidateProfile() {
            super();
            }
// Getters and Setters 

///这是我的工作经历详细信息实体////////

    package com.cfa.project.premiumjobportal.model;
import java.io.Serializable;
import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.ManyToOne;
    import javax.persistence.Table;
    import javax.xml.bind.annotation.XmlRootElement;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
//Experience类，与CandidateProfile类连接
    @Entity
    @Table(name="experience_details")
    @JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
    @XmlRootElement
    public class ExperienceDetails implements Serializable {
 private static final long serialVersionUID = 1L;
@Id
        @GeneratedValue
        private int id;
@Column(name = "tot_experenice", length = 2)
        private String totExperience;
@Column(name = "companies_month_experience")
        private String companiesMonthExperience;
@Column(name = "skills")
        private String _skills;
@Column(name = "extra_curricular")
        private String extraCurricular;
 private String notes;
/* Mapping : Joining with Candidate table */
        @ManyToOne
        private CandidateProfile candidateProfile;
/*Constructor*/
        public ExperienceDetails() {
            super();
        }
/*Constructor using fields*/
        /**
         * @param id
         * @param totExperience
         * @param companiesMonthExperience
         * @param _skills
         * @param extraCurricular
         * @param notes
         * @param candidateProfile
         */
        public ExperienceDetails(int id, String totExperience, String companiesMonthExperience, String _skills,
                String extraCurricular, String notes, CandidateProfile candidateProfile) {
            super();
            this.id = id;
            this.totExperience = totExperience;
            this.companiesMonthExperience = companiesMonthExperience;
            this._skills = _skills;
            this.extraCurricular = extraCurricular;
            this.notes = notes;
            this.candidateProfile = candidateProfile;
        }
/* Generating Getters and setters */

///这是我的角色实体//////

    import java.io.Serializable;
    import java.util.List;
import javax.persistence.CascadeType;
    import javax.persistence.Column;
    import javax.persistence.Entity;
    import javax.persistence.FetchType;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.OneToMany;
    import javax.persistence.Table;
    import javax.xml.bind.annotation.XmlRootElement;
import com.fasterxml.jackson.annotation.JsonBackReference;
    import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@Entity
    @Table(name="role")
    @JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
    @XmlRootElement
    public class Role implements Serializable {
 private static final long serialVersionUID = 1L;
@Id
        @GeneratedValue
        private int id;
@Column(length = 10)
        private String name;
@OneToMany(mappedBy = "roleName", fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
        @JsonBackReference
        private List candidateProfiles;
@OneToMany(mappedBy = "companyRoleName", fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
        @JsonBackReference
        private List recruiterDetails;

我遇到了这个错误----------------

Failed to evaluate Jackson deserialization for type [[simple type, class 
com.demo.project.premiumjobportal.model.CandidateProfile]]: 
com.fasterxml.jackson.databind.JsonMappingException: Multiple back-reference 
properties with name 'defaultReference'

请帮我解决这个问题。我已经到处搜索并尝试了各种解决方案，但仍然无法解决这个错误。

- Rakesh kumar

Answer 1

如果在您的项目中多次使用@JsonBackReference，您需要使用特定的引用名称来区分它们。

在Role实体类中，您已经两次使用了@JsonBackReference：

@OneToMany(mappedBy = "roleName", fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
@JsonBackReference
private List candidateProfiles;

@OneToMany(mappedBy = "companyRoleName", fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
@JsonBackReference
private List recruiterDetails;

您应该将它更改为：

@OneToMany(mappedBy = "roleName", fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
@JsonBackReference(value="candidate-profiles")
private List candidateProfiles;

@OneToMany(mappedBy = "companyRoleName", fetch = FetchType.LAZY,cascade = CascadeType.REMOVE)
@JsonBackReference(value="recruiter-details")
private List recruiterDetails;

- Arjit