Hibernate连接两个实体

Question

• AnsprechPartner
• Lieferant

ansprechpartner.java

@Entity
@Table(name = "ANSPRECHPARTNER")
@EntityListeners(AuditingEntityListener.class)
@JsonIgnoreProperties(value = {"anlageAm", "updatedAt"}, allowGetters = true)
public class Ansprechpartner {

...

@NotNull
@ManyToOne
@JoinColumn(name = "lief_code", foreignKey=@ForeignKey(name = "APART_LIEF_FK"))
private Lieferanten liefCode;

public Lieferanten getLiefCode() {
    return liefCode;
}

public void setLiefCode(Lieferanten liefCode) {
    this.liefCode = liefCode;
}

...

}

lieferant.java

@Entity
@Table(name = "LIEFERANTEN")
@EntityListeners(AuditingEntityListener.class)
@JsonIgnoreProperties(value = {"anlageAm"}, allowGetters = true)
public class Lieferanten {

...

@Id
private String code;

@OneToMany(mappedBy = "liefCode")
private Set<Ansprechpartner> apart;


public String getCode() {
    return code;
}


public void setCode(String code) {
    this.code = code;
}

public Set<Ansprechpartner> getApart() {
    return apart;
}


public void setApart(Set<Ansprechpartner> apart) {
    this.apart = apart;
}

...

}

@RestController
@RequestMapping("/apart")
public class AnsprechpartnerController {

...

@GetMapping("/all/{id}")
public Ansprechpartner getApartWithId(@PathVariable("id") long id) {

    Ansprechpartner apart = apartRepository.findOne(id);

    return apartRepository.findOne(id);
}

}

在我的AnsprechPartner.java中，我是这样做的：

    @NotNull
    @JsonIgnoreProperties("apart")
//  @JsonManagedReference
    @ManyToOne
    @JoinColumn(
         name = "lief_code", 
         foreignKey=@ForeignKey(name = "APART_LIEF_FK")
    )
    private Lieferanten liefCode;

在我的Lieferanten.java中，我是这样做的：

//  @JsonBackReference
    @JsonIgnoreProperties("liefCode")
    @OneToMany(mappedBy = "liefCode", fetch = FetchType.LAZY)
    private Set<Ansprechpartner> apart;

Answer 1

为了避免无限递归，可以使用@JSONManagedReference&@JSONBackReference Json无限递归是序列化具有双向关系的Java对象时最常见的问题之一。

@JSONManagedReference:带有注释的部件通常会被序列化。@jsonbackreference:带有注释的部分将从序列化中省略。

比如：

   @JsonBackReference
   private Set<Ansprechpartner> apart;