找不到類org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor一對一映射hibernate的序列化程式

我有以下 2 個模型類：

package com.example.demo.model;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name = "casefiles")
public class CaseFile {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    
    @Column(name="description")
    private String description;
    
    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "patient_id")
    private Patient patient;
    
    public CaseFile() {}

    public CaseFile(String description, Patient patient) {
        super();
        this.description = description;
        this.patient = patient;
    }

    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Patient getPatient() {
        return patient;
    }

    public void setPatient(Patient patient) {
        this.patient = patient;
    }
}

和

package com.example.demo.model;

import java.time.LocalDate;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EnumType;
import javax.persistence.Enumerated;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Entity
@Table(name = "patients")
public class Patient {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    
    @Column(name = "name")
    private String name;
    
    @Enumerated(EnumType.STRING)
    @Column(name = "gender")
    private Gender gender;
    
    @Column(name = "birth_date")
    private LocalDate birthDate;
    
    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL, mappedBy = "patient")
    private CaseFile casefile;
    
    public Patient() {}

    public Patient(String name, Gender gender, LocalDate birthDate) {
        super();
        this.name = name;
        this.gender = gender;
        this.birthDate = birthDate;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Gender getGender() {
        return gender;
    }

    public void setGender(Gender gender) {
        this.gender = gender;
    }

    public LocalDate getBirthOfDate() {
        return birthDate;
    }

    public void setBirthOfDate(LocalDate birthDate) {
        this.birthDate = birthDate;
    }   

}

在我的控制器中，當我嘗試通過 id 獲取案例檔案時：

@GetMapping("/casefiles/{id}")
    public ResponseEntity<CaseFile> getCasefileById(@PathVariable Long id) {
        CaseFile casefile = caseFileRepository.findById(id).orElseThrow(() -> new ResourceNotFoundException("No casefile found with the id "   id));
        return ResponseEntity.ok(casefile);
    }

我收到這個錯誤：沒有找到類 org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor 的序列化程式，也沒有發現創建 BeanSerializer 的屬性（為了避免例外，禁用 SerializationFeature.FAIL_ON_EMPTY_BEANS）（通過參考鏈：com.example.demo.model .CaseFile["患者"]->com.example.demo.model.Patient$HibernateProxy$I2MAWVYg["hibernateLazyInitializer"])

uj5u.com熱心網友回復：

那是因為患者上的 FetchType.LAZY。在延遲加載的一對一連接上，Hibernate 會將代理放入變數中。

您需要在序列化之前初始化關系，例如使用 JOIN FETCH。

查看五種可能的初始化關系的方法：https : //thorben-janssen.com/5-ways-to-initialize-lazy-relations-and-when-to-use-them/

uj5u.com熱心網友回復：

我認為問題在于您沒有為 casefile 提供 getter 和 setter。因此，您無法獲取該值。

 public LocalDate getCaseFile() {
        return caseFile;
    }

    public void setCaseFile(CaseFile casefile) {
        this.caseFile = caseFile;
    }   

標籤：爪哇 春天 休眠 jpa

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