@JsonIgnore @JsonIdentityInfo 处理Hibernate 循环引用的问题

enterprise和user一对一的关系：

@Entity@Table(name = "enterprise")public class Enterprise extends BaseEntity {    private static final long serialVersionUID = 1L;    private User user;    private String name;    @OneToOne(mappedBy = "enterprise")    public User getUser() {        return user;    }    public void setUser(User user) {        this.user = user;    }    ...setter/getter}

@Entity@Table(name = "APP_USER")public class User extends BaseEntity {    @NotEmpty    @Column(name = "FIRST_NAME", nullable = false)    private String firstName;    @Column(name = "LAST_NAME", nullable = true)    private String lastName;    @OneToOne    private Enterprise enterprise;}

在controller中，使用ResponseEntity来返回enterprise转换为json之后的字符串。如果不做任何处理，因为enterprise拥有user字段，而user也拥有enterprise字段，自此出现了循环引用的问题，程序将会出错。

使用@JsonIgnore

@JsonIgnore@OneToOne(mappedBy = "enterprise")public User getUser() {    return user;}

在getUser方法上添加@JsonIgnore注释，返回的enterprise json对象中，将不包括user对象。
但是如果我们希望在enterprise json对象中包括user的json对象该怎么办呢？

使用@JsonIdentityInfo

Annotation used for indicating that values of annotated type or property should be serializing so that instances either contain additional object identifier (in addition actual object properties), or as a reference that consists of an object id that refers to a full serialization. In practice this is done by serializing the first instance as full object and object identity, and other references to the object as reference values.

在user类或者enterprise类上增加该注解即可。

@Entity@Table(name = "enterprise")@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")public class Enterprise extends BaseEntity