如何解决spring boot插入数据时外键一直为零的问题？

Question

用户.java

package com.spring.demo.model;

import java.util.Date;

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.Lob;

import javax.persistence.OneToOne;

import javax.persistence.Table;

import javax.persistence.Transient;

@Entity

@Table(name="user")

public class User {

    @Id

    @GeneratedValue(strategy=GenerationType.IDENTITY)

    @Column(name="user_id")

    private int id;

    private String fName;

    private String lName;

    @Column(unique=true,nullable=true)

    private String email;

    @Column(unique=true,nullable=true)

    private long mobile;

    private Date dob;

    @Lob

    private byte[] image;   

    @Transient

    private String base64Image;

    @OneToOne(cascade=CascadeType.ALL,fetch =FetchType.EAGER)

    @JoinColumn(name="userCredential_id")

    private UserCredential userCredential;

    @OneToOne(cascade=CascadeType.ALL,fetch =FetchType.EAGER)

    @JoinColumn(name="add_id")

    private Address address;

    public Address getAddress() {

        return address;

    }

    public void setAddress(Address address) {

        this.address = address;

    }

    public int getId() {

        return id;

    }

    public void setId(int id) {

        this.id = id;

    }

    public String getfName() {

        return fName;

    }

    public void setfName(String fName) {

        this.fName = fName;

    }

    public String getlName() {

        return lName;

    }

    public void setlName(String lName) {

        this.lName = lName;

    }

    public String getEmail() {

        return email;

    }

    public void setEmail(String email) {

        this.email = email;

    }

    public long getMobile() {

        return mobile;

    }

    public void setMobile(long mobile) {

        this.mobile = mobile;

    }

    public Date getDob() {

        return dob;

    }

Answer 1

您似乎正在尝试对两个双向关系进行建模：User<->UserCredentials和：User<->&nbsp;UserAddress。但是您真正在创建以下四种关系：User&nbsp;->&nbsp;UserCredentialsUser&nbsp;<-&nbsp;UserCredentialsUser&nbsp;->&nbsp;UserAddressUser&nbsp;<-&nbsp;UserAddress为了解决这个问题，您需要使用mappedBy.&nbsp;

Answer 2

问题在于反向引用。Hibernate 无法为您维护这一点。假设您保存了用户对象。它创建一个凭证行并生成 id。它创建地址和 ID。它更新用户对象上的 cred_id 和 add_id，然后为其创建一行并生成 id 并返回该值。此时您需要将您的用户对象添加到凭证和地址并再次保存。