Spring boot和mySQL获取一对多关系的请求

【问题标题】：Spring boot and mySQL get request for one to many relationshipSpring boot和mySQL获取一对多关系的请求
【发布时间】：2020-12-06 10:26:00
【问题描述】：

我在 mySQL 中有 3 个表，用户、机构和角色

  1. 用户与机构之间的一对多关系（一个用户可以在一个机构工作，一个机构可以有多个用户）

我的数据库中的机构已经插入，用户只能在特定的现有机构工作。

我为用户和机构手动将 2 条记录添加到我的数据库中。

但是当我发送 getAllUsers 或 getAllInstitutions 请求时，我得到以下 json 主体，这是一个无限循环。

---------用户模型--------

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@ToString

@Entity
@Table(name = "user")
public class User {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="user_Id")
    private int userId;
    @Column(name="name")
    private String name;
    @Column(name="lastname")
    private String lastname;
    @Column(name="email")
    private String email;
    @Column(name="password")
    private String password;
    @Column(name="isActive")
    private boolean isActive;
    @Column(name="lastActive")
    private String lastActive;
    @Column(name="createdDate")
    private String createdDate;
    @Column(name="isBlocked")
    private boolean isBlocked;
    
    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "institution_id", nullable = false)
    private Institution institution;
    
    @ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
    @JoinTable(name = "user_has_role",
            joinColumns = {
                    @JoinColumn(name = "user_id", referencedColumnName = "user_id",
                            nullable = false, updatable = true)},
            inverseJoinColumns = {
                    @JoinColumn(name = "role_id", referencedColumnName = "role_id",
                            nullable = false, updatable = true)})
    private Set<Role> roles = new HashSet<>();

}

---------机构模式------------

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@ToString

@Entity
@Table(name = "institution")
public class Institution {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="institution_Id")
    private int institutionId;
    @Column(name="name")
    private String name;
    @Column(name="type")
    private String type;
    @Column(name="location")
    private String location;
    @OneToMany(mappedBy = "institution", fetch = FetchType.LAZY)
    private Set<User> user;
    
}

---------榜样---------

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@ToString

@Entity
@Table(name = "role")
public class Role {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="role_Id")
    private int roleId;
    @Column(name="name")
    private String name;
    @Column(name="description")
    private String description;
    @ManyToMany(mappedBy = "roles", fetch = FetchType.LAZY)
    private Set<User> users = new HashSet<>();

}

-------- 控制器-----------

@GetMapping("/getAllUsers")
public List<User> getAllUsers() {
    return (List<User>) userrepository.findAll();
}

@PostMapping("/addUser")
public String addUser(@RequestBody User user) {
    userrepository.save(user);
    return "role saved with name: " + user.getName();
}

@GetMapping("/getAllInstitutions")
public List<Institution> getAllInstitutions() {
    return (List<Institution>) institutionrepository.findAll();
}

@PostMapping("/addInstitution")
public String addInstitution(@RequestBody Institution institution) {
    institutionrepository.save(institution);
    return "institution saved with name: " + institution.getName();
}

---------getAllInstitutions的api请求体循环错误---------------

[
{
    "institutionId": 1,
    "name": "Bank Byblos",
    "type": "Bank",
    "location": "sen el fil",
    "user": [
        {
            "userId": 3,
            "name": "user1",
            "lastname": "testtest",
            "email": "user1@hotmail.com",
            "password": "user1123",
            "lastActive": "11/11/21",
            "createdDate": "06/05/20",
            "institution": {
                "institutionId": 1,
                "name": "Bank Byblos",
                "type": "Bank",
                "location": "sen el fil",
                "user": [
                    {
                        "userId": 3,
                        "name": "user1",
                        "lastname": "testtest",
                        "email": "user1@hotmail.com",
                        "password": "user1123",
                        "lastActive": "11/11/21",
                        "createdDate": "06/05/20",
                        "institution": {
                            "institutionId": 1,
                            "name": "Bank Byblos",
                            "type": "Bank",
                            "location": "sen el fil",
                            "user": [
                                {
                                    "userId": 3,
                                    "name": "user1",
                                    "lastname": "testtest",
                                    "email": "user1@hotmail.com",
                                    "password": "user1123",
                                    "lastActive": "11/11/21",
                                    "createdDate": "06/05/20",
                                    "institution": {
                                        "institutionId": 1,
                                        "name": "Bank Byblos",
                                        "type": "Bank",
                                        "location": "sen el fil",
                                        "user": [
                                            {
                                                "userId": 3,
                                                "name": "user1",
                                                "lastname": "testtest",
                                                "email": "user1@hotmail.com",
                                                "password": "user1123",
                                                "lastActive": "11/11/21",
                                                "createdDate": "06/05/20",
                                                "institution": {
                                                    "institutionId": 1,
                                                    "name": "Bank Byblos",
                                                    "type": "Bank",
                                                    "location": "sen el fil",
                                                    "user": [
                                                        {
                                                            "userId": 3,
                                                            "name": "user1",
                                                            "lastname": "testtest",
                                                            "email": "user1@hotmail.com",
                                                            "password": "user1123",
                                                            "lastActive": "11/11/21",
                                                            "createdDate": "06/05/20",
                                                            "institution": {
                                                                "institutionId": 1,
                                                                "name": "Bank Byblos",
                                                                "type": "Bank",
                                                                "location": "sen el fil",
                                                                "user": [
                                                                    {
                                                                        "userId": 3,
                                                                        "name": "user1",
                                                                        "lastname": "testtest",
                                                                        "email": "user1@hotmail.com",
                                                                        "password": "user1123",
                                                                        "lastActive": "11/11/21",
                                                                        "createdDate": "06/05/20",
                                                                        "institution": {
                                                                            "institutionId": 1,
                                                                            "name": "Bank Byblos",
                                                                            "type": "Bank",
                                                                            "location": "sen el fil",
                                                                            "user": [
                                                                                {

---------getAllÙsers的api请求体循环错误---------------

[
{
    "userId": 3,
    "name": "user1",
    "lastname": "testtest",
    "email": "user1@hotmail.com",
    "password": "user1123",
    "lastActive": "11/11/21",
    "createdDate": "06/05/20",
    "institution": {
        "institutionId": 1,
        "name": "Bank Byblos",
        "type": "Bank",
        "location": "sen el fil",
        "user": [
            {
                "userId": 3,
                "name": "user1",
                "lastname": "testtest",
                "email": "user1@hotmail.com",
                "password": "user1123",
                "lastActive": "11/11/21",
                "createdDate": "06/05/20",
                "institution": {
                    "institutionId": 1,
                    "name": "Bank Byblos",
                    "type": "Bank",
                    "location": "sen el fil",
                    "user": [
                        {
                            "userId": 3,
                            "name": "user1",
                            "lastname": "testtest",
                            "email": "user1@hotmail.com",
                            "password": "user1123",
                            "lastActive": "11/11/21",
                            "createdDate": "06/05/20",
                            "institution": {
                                "institutionId": 1,
                                "name": "Bank Byblos",
                                "type": "Bank",
                                "location": "sen el fil",
                                "user": [
                                    {
                                        "userId": 3,
                                        "name": "user1",
                                        "lastname": "testtest",
                                        "email": "user1@hotmail.com",
                                        "password": "user1123",
                                        "lastActive": "11/11/21",
                                        "createdDate": "06/05/20",
                                        "institution": {
                                            "institutionId": 1,
                                            "name": "Bank Byblos",
                                            "type": "Bank",
                                            "location": "sen el fil",
                                            "user": [
                                                {
                                                    "userId": 3,
                                                    "name": "user1",
                                                    "lastname": "testtest",
                                                    "email": "user1@hotmail.com",
                                                    "password": "user1123",
                                                    "lastActive": "11/11/21",
                                                    "createdDate": "06/05/20",
                                                    "institution": {
                                                        "institutionId": 1,
                                                        "name": "Bank Byblos",
                                                        "type": "Bank",
                                                        "location": "sen el fil",
                                                        "user": [
                                                            {
                                                                "userId": 3,
                                                                "name": "user1",
                                                                "lastname": "testtest",
                                                                "email": "user1@hotmail.com",
                                                                "password": "user1123",
                                                                "lastActive": "11/11/21",
                                                                "createdDate": "06/05/20",
                                                                "institution": {
                                                                    "institutionId": 1,
                                                                    "name": "Bank Byblos",
                                                                    "type": "Bank",
                                                                    "location": "sen el fil",
                                                                    "user": [

我有 2 个用户添加到我的数据库 user1 和 user2 中，并且添加到我的数据库 user1 的 2 个机构属于一个，而 user2 属于另一个（使用用户表中的外键机构 ID） 请问你能帮我修一下吗？

【问题讨论】：

    标签： java mysql spring-boot many-to-many postman


    【解决方案1】：

    尝试修改你的代码如下：

    @Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@ToString

@Entity
@Table(name = "institution")
public class Institution {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="institution_Id")
    private int institutionId;
    @Column(name="name")
    private String name;
    @Column(name="type")
    private String type;
    @Column(name="location")
    private String location;

    @OneToMany(mappedBy = "institution", fetch = FetchType.LAZY)
    @JsonIgnoreProperties(value = {"institution"})
    private Set<User> user;
    
}

    使用@JsonIgnoreProperties 注释忽略Institution 模型中用户的属性设置。 现在它不会循环了，因为你在获取机构数据时不会得到信息。

    尝试在您的User 模型中添加@JsonIgnoreProperties，它应该可以解决您的问题。

    @Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@ToString

@Entity
@Table(name = "user")
public class User {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="user_Id")
    private int userId;
    @Column(name="name")
    private String name;
    @Column(name="lastname")
    private String lastname;
    @Column(name="email")
    private String email;
    @Column(name="password")
    private String password;
    @Column(name="isActive")
    private boolean isActive;
    @Column(name="lastActive")
    private String lastActive;
    @Column(name="createdDate")
    private String createdDate;
    @Column(name="isBlocked")
    private boolean isBlocked;
    
    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "institution_id", nullable = false)
    @JsonIgnoreProperties(value = {"user"})
    private Institution institution;
    
    @ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)

    【讨论】：

    • 对于用户？我怎么知道用户在哪个机构工作，我现在就试试，谢谢..
    • 对于用户，请保持原样。它现在应该可以正常工作了。
    • 我试过它仍然给出相同的循环我猜它不应该是双向的？我应该从机构中删除这组用户吗？ idk 其实
    • 对不起，我弄错了，我编辑了，这样试试。
    • 好的，它现在对机构有效，它为我提供了该机构用户的所有机构，但现在我得到一个错误 getAllUsers ` { "timestamp": "2020-08-17T10:01:21.921 +00:00”、“状态”：500、“错误”：“内部服务器错误”、“消息”：“”、“路径”：“/getAllUsers”}`
    猜你喜欢
    • 2019-11-03
    • 1970-01-01
    • 1970-01-01
    • 2020-07-04
    • 2022-01-05
    • 2023-04-10
    • 2017-10-28
    • 1970-01-01
    • 2019-01-24
    相关资源
    最近更新 更多
    热门标签
    Java Python linux javascript Mysql C# Docker 算法 前端 SpringBoot Redis Vue spring 设计模式 .net core .net kubernetes c++ 数据库 数据结构 大数据 js 机器学习 微服务 Android Go 程序员 面试 JVM ASP.net core 云原生 人工智能 后端 PHP git CSS golang k8s Nginx Django mybatis 深度学习 多线程 React 架构 devops 爬虫 云计算 Spring Boot LeetCode