java – StackOverflow在双向对象上使用Hibernate和Jackson时出现异常

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我正在尝试一些休眠.以下是我正在使用的pojo,

@Entity
@Table(name = "person")
public class Person {

    @Id
    @GeneratedValue
    @Column(name = "person_id")
    private long person_id;


    @Column(name = "name")
    private String name;


    @Column(name = "Address")
    private String Address;


    @OneToMany(fetch = FetchType.EAGER, mappedBy = "person" )
    private Set<Phone> phone;

        //Getters ande Setters

}


@Entity
@Table(name = "phone")
public class Phone{

    @Id
    @GeneratedValue
    @Column(name = "phone_id")
    private long phone_id;


    @Column(name = "name")
    private String name;

         @ManyToOne(cascade = CascadeType.MERGE,fetch = FetchType.EAGER)
    @JoinColumn(name = "person_id")
    private Person person ;

        //Getters ande Setters


}

我想要的是当我从人那里获取记录并需要相应的所有电话细节时. (就像选择*来自人)我有大约1360个人的数据,几乎是手机的两倍.但由于某种原因,错误被抛出.我无法看到完整的错误堆栈.以下是我得到的错误.

at
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:505)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:639)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:505)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:639)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:117)
~[jackson-databind-2.4.6.jar:2.4.6] at
com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:23)
~[jackson-databind-2.4.6.jar:2.4.6] at
…..

我无法发布我得到的所有错误

解决方法:

使用JsonManagedReference和JsonBackReference注释可以解决您的问题.

While jackson trying to convert objects to json, visits objects and
their attributes. So if objects have bi-directional relations, for
jackson we need to think about cyclic dependencies. Jackson starts
serialize person and see the phone list and take a phone from list and
start serialize phone and sees person in phone and take person from
phone and start serilize it bla bla bla so this is an endless loop. If
jackson sees these annotations, stops and breaks the loop.

尝试下面的代码;

@Entity
@Table(name = "person")
public class Person {

    @Id
    @GeneratedValue
    @Column(name = "person_id")
    private long person_id;    

    @Column(name = "name")
    private String name;

    @Column(name = "Address")
    private String Address;
    @JsonManagedReference
    @OneToMany(fetch = FetchType.EAGER, mappedBy = "person" )
    private Set<Phone> phone;

    // Getters and Setters

}

@Entity
@Table(name = "phone")
public class Phone{

    @Id
    @GeneratedValue
    @Column(name = "phone_id")
    private long phone_id;

    @Column(name = "name")
    private String name;

    @ManyToOne(cascade = CascadeType.MERGE,fetch = FetchType.EAGER)
    @JoinColumn(name = "person_id")
    @JsonBackReference
    private Person person;

    // Getters and Setters

}

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