在Springboot中将数据插入关系数据库

Question

我正在从事一个教育目的项目，（课程表，课程表=一对多）与（课程表，作业表=一对多）之间存在关系，首先我插入课程info（title，description）然后再插入另一个POST请求，然后插入课程，然后再发出第三个请求，POST插入作业，但是当我尝试使用GET请求获得课程时，发生的事情是我得到了很多像这样重复的JSON格式

我将在春季靴子中首先向您展示模型

课程模型（删除了一些不相关的代码以使其简短）：

@Entity
public class Course {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    @NotNull
    @Column(nullable = false)
    private String title;

    @Lob
    private String description;

    @NotNull
    @Column(nullable = false)
    private String published;

    @NotNull
    @Column(nullable = false)
    private Date publishedOn;

    @OneToMany(mappedBy = "course")
    private List<Assignment> assignments = new ArrayList<>();

    @OneToMany(mappedBy = "course")
    private List<Lesson> lessons = new ArrayList<>();

    public Course() {}

    public Course(String title, String description,
                  String published, Date publishedOn) {
        this.title = title;
        this.description = description;
        this.published = published;
        this.publishedOn = publishedOn;
    }

    public List<Assignment> getAssignments() {
        return assignments;
    }

    public void addAssignments(Assignment assignment) {
        this.assignments.add(assignment);
    }

    public void removeAssignments(Assignment assignment) {
        this.assignments.remove(assignment);
    }

    public List<Lesson> getLessons() {
        return lessons;
    }

    public void addLessons(Lesson lesson) {
        this.lessons.add(lesson);
    }

    public void removeLessons(Lesson lesson) {
        this.lessons.remove(lesson);
    }
}

课程模型（删除了一些不相关的代码）：

@Entity
public class Lesson {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    @NotNull
    @Lob
    @Column(nullable = false)
    private String reading;

    @ManyToOne
    private Course course;

    public Lesson() {}

    public Lesson(String reading, Course course) {
        this.reading = reading;
        this.course = course;
    }

    public String getReading() {
        return reading;
    }

    public void setReading(String reading) {
        this.reading = reading;
    }

    public Course getCourse() {
        return course;
    }

    public void setCourse(Course course) {
        this.course = course;
    }


}

与分配模型相同，我将向您展示如何插入课程

pubcli ResponseEntity addLesson(long id, LessonDto lessonDto) {
        Course course = courseRepository.findCourseById(id);
        Lesson lesson = new Lesson();
        lesson.setReading(lessonDto.getReading());
        lesson.setCourse(course);
        course.addLessons(lesson);
        lessonRepository.save(lesson);
        return new ResponseEntity("Lesson added to this course -" +
                course.getTitle() + "-", HttpStatus.OK);
    }