mysql - 在 spring hibernate 中使用 OneToOne 关系防止在父表中插入空值

Question

我有两个具有 OneToOne 关系双向映射的表 User 和 ProfilePic。为用户上传个人资料图片时，它会在数据库中创建具有空值的新用户。我需要防止插入新用户并且只想在 ProfilePic 表中插入值。请不要标记为重复或否决我是 hibernate 新手。相关代码如下:

用户类别:

    @Entity
@Table(name = "user_details")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int userId;
    private String firstName;
    private String lastName;
    private String gender;
    @Temporal(TemporalType.DATE)
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    private Date dob;
    private String email;
    private String address;
    private String username;
    private String password;
    private String phoneNumber;
    private Boolean isActive;
    private String role;
    @OneToOne(mappedBy = "user")
    private ProfilePic profilePic;
    @OneToMany(mappedBy = "user")
    private List<Login> login = new ArrayList<>();

-----getter setter---
}

个人资料图片类:

@Entity
public class ProfilePic {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int imageId;
    private String image_url;
    @OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    @JoinColumn(name = "userId", nullable = false)
    private User user;
---getter setter---
}

存储库类:

@Override
    public void saveProfilePic(ProfilePic profilePic) {
        HibernateUtil.getSession(sessionFactory).save(profilePic);
    }

Controller 类:

@RequestMapping(value = "/uploadProfileimage", method = RequestMethod.POST)
    public String uploadProfileImage(@ModelAttribute User user, @ModelAttribute ProfilePic profilePic,
            @RequestParam("image") CommonsMultipartFile file, Model model) {
        String imageUrl = "";
        if (!file.getOriginalFilename().isEmpty()) {
            imageUrl = ImageUtil.writeImageToFile(file);
            profilePic.setImage_url(imageUrl);
            profilePic.setUser(user);
            pictures.add(profilePic);
            userService.saveProfilePic(profilePic);
        }
        return "redirect:/getProfile?userId=" + user.getUserId();
    }

日志:

Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
Hibernate: insert into user_details (address, dob, email, firstName, gender, isActive, lastName, password, phoneNumber, role, username, userId) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: insert into ProfilePic (image_url, userId, imageId) values (?, ?, ?)
Hibernate: select user0_.userId as userId1_7_0_, user0_.address as address2_7_0_, user0_.dob as dob3_7_0_, user0_.email as email4_7_0_, user0_.firstName as firstNam5_7_0_, user0_.gender as gender6_7_0_, user0_.isActive as isActive7_7_0_, user0_.lastName as lastName8_7_0_, user0_.password as password9_7_0_, user0_.phoneNumber as phoneNu10_7_0_, user0_.role as role11_7_0_, user0_.username as usernam12_7_0_, profilepic1_.imageId as imageId1_6_1_, profilepic1_.image_url as image_ur2_6_1_, profilepic1_.userId as userId3_6_1_ from user_details user0_ left outer join ProfilePic profilepic1_ on user0_.userId=profilepic1_.userId where user0_.userId=?

预期结果:仅在 ProfilePic 表中插入数据并关联用户 ID实际结果:User和ProfilePic这两个表都插入了数据。创建的新用户在所有列中均具有空值。帮助将不胜感激。我深陷其中。

Answer 1

问题是，如果用户 id 为 null，则只在 ProfilePic 中插入数据不是问题，因此没有用户与此图片相关联。

但是如果要向ProfilePic中插入数据时，需要将用户id插入到用户表中，否则用户id将不可用。

因此，例如在 MYSQL 中，如果您运行此查询:

INSERT INTO profile_pic (image_id, image_url, user_id) VALUES ('1', "/image", '1');

您将遇到错误(无法添加或更新子行:外键约束失败(stackoverflow。profile_pic，CONSTRAINT user_id 外键 (user_id) 引用 user (user_id)))所以基本上没有id为1的用户。

解决方案是使用单向映射，换句话说，用户将引用profile_pic，但profile_pic不会。

您应该将模型更改为:用户类:

    @Entity
    @Table(name = "user_details")
    public class User {
        @OneToOne
        private ProfilePic profilePic;
        // other fields, getters and setters
    }

个人资料图片类:

@Entity
public class ProfilePic {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int imageId;
    private String image_url;
    // getters and setters
}

然后您将只能插入 ProfilePic。我希望这对你有用!