插入子和父 JSON Spring Boot

Question

我的 Spring Boot App 数据休息中有 3 个实体，Appusers、Teacher 和 Student

1. 应用用户

   @Id
   @GeneratedValue(strategy = GenerationType.AUTO) 
   @Column(name= "appuserId", updatable=false)
   private Long appuserId;     
   @Column(name = "username")
   private String username;
   
   @Column(name = "fullname")
   private String fullName;
   
   @Column(name = "email")
   private String email;   
   
   @Column(name = "password")
   private String password;
   
   @OneToOne(mappedBy = "appuser")
   private Teacher teacher;
   
   @OneToOne(mappedBy = "appuser")
   private Student student;
   

2. 老师

   @Id
   @GeneratedValue(strategy=GenerationType.AUTO)
   @Column(name = "teacherId" , updatable = false)
   private Long teacherId;
   
   @Column(name= "firstname")
   private String firstName;
   
   @Column(name = "lastname")
   private String lastName;
   
   @Column(name="designation")
   private String designation;
   
   @OneToOne(cascade = CascadeType.ALL)
   @JoinColumn(name = "appuserId", nullable = true)
   private Appuser appuser;
   
   @OneToMany(cascade = CascadeType.ALL, orphanRemoval=true ,mappedBy="teacher")
   @JsonIgnore
   private List<Course> courses;
   

3. 学生

   @Id
   @GeneratedValue(strategy = GenerationType.AUTO) 
   @Column(name= "studentId", updatable=false)
   private Long studentId;
   
   @Column(name = "firstName")
   private String firstName;
   
   @Column(name = "lastName")
   private String lastName;
   
   @Column(name = "enrolledSince")
   private String enrolledSince;
   
   @OneToOne(cascade = CascadeType.ALL)
   @JoinColumn(name = "appuserId", nullable = false)
   private Appuser appuser;
   
   @OneToMany(cascade = CascadeType.ALL,orphanRemoval=true, mappedBy="student")
   @JsonIgnore
   private List<CourseStudent> courseStudents;
   

我可以在邮递员中使用 json 格式插入 appusers 表，并且运行良好。但是当我尝试在教师或学生表中插入时，appusers 中的结果为空。它不应该为空，因为教师和学生是应用程序用户的外键。

Answer 1

当您尝试在教师或学生表中插入时，请确保您在持久化时将值设置为 appuser。

Student std =new Student();
// create an object of appuser,set its vaue and assign it to student object
 Appuser ap = new Appuser();
 // assigning values to the appuser object as ap.setfullname="...";... so on
 std.setAppuser=ap;

现在持久化这个学生对象，条目将反映在映射表中 或者你可以在已经持久化的std对象中设置appuser的id。

Answer 2

这不应该发生。当您保存教师或学生时，您应该指定数据库中已经存在的 appuser。并且使用appuserId代替Appuser，这足以识别它属于哪个appuser。

您可以在保存教师或学生并请求加入数据库后获取您的应用用户。