Show OneToMany connection

Question

I am trying in vain to display a list of objects of type calendar entries. I use a @OneToMany and @ManyToOne assertion. If I call up my controller with Postman, I "only" see my user, which also contains my entries. How can I display everything here without an extra query in a repository?

KalenderEintraege:

@JsonIgnore
@ManyToOne
@JoinColumn(name = "user_id")
private User user;

User:

@JsonIgnore
@OneToMany(mappedBy = "user", cascade = CascadeType.ALL, orphanRemoval = true)
private List<KalenderEintraege> eintrage = new ArrayList<KalenderEintraege>();

Backend (RestController):

@GetMapping("/InsertInto")
public void einfuegen() {

    User user = new User();
    user.setName("Ben");

    KalenderEintraege kalender = new KalenderEintraege();
    kalender.setBeschreibung("Test");
    kalender.setDatum(new Date());
    kalender.setUser(user);

    List<KalenderEintraege> listKalender = new ArrayList<KalenderEintraege>();

    listKalender.add(kalender);

    user.setEintrage(listKalender);

    userRepro.save(user);

}

@GetMapping("/All")
public List<User> getUser() {

    return (List<User>) userRepro.findAll();
}

Answer 1

Both directions were annotated with @JsonIgnore, so it won't display relational data, but will query it anyways, try activate "show sql" in console with these settings:

// add these in property file and you can see generated sql
spring.jpa.show-sql: true
spring.jpa.properties.hibernate.format_sql=true

However, getting rid of both @JsonIgnore will cause stackoverflow error, you can try @JsonIgnoreProperties annotation to solve it:

@JsonIgnoreProperties("user") // your Table name
@OneToMany(mappedBy = "user", cascade = CascadeType.ALL, orphanRemoval = true)
private List<KalenderEintraege> eintrage = new ArrayList<KalenderEintraege>();


@JsonIgnoreProperties("KalenderEintraege") // your Table name
@ManyToOne
@JoinColumn(name = "user_id")
private User user;