jackson解决对象中存在双向引用导致的无限递归问题

爱被打了一巴掌 2022-05-17 02:07 151阅读 0赞

jackson中的@JsonBackReference和@JsonManagedReference，以及@JsonIgnore均是为了解决对象中存在双向引用导致的无限递归问题.

@JsonBackReference和@JsonManagedReference：这两个标注通常配对使用，通常用在父子关系中。

@Entity
    @Table(name = "Items")
    public class Item {
        @Id
        @GenericGenerator(strategy="uuid",name="uuid")
        @GeneratedValue(generator = "uuid")
        private String id;
    
        private String itemName;
    
    
        private Integer itemNum;
    
        @ManyToOne(cascade = CascadeType.ALL,fetch = FetchType.LAZY)
        @JsonBackReference
        @JoinColumn(name="b_id")
        private Base base;
    
    
        public Base getBase() {
            return base;
        }
    
        public void setBase(Base base) {
            this.base = base;
        }
    
        public Item(){
    
        }
    
    
        public String getId() {
            return id;
        }
    
        public void setId(String id) {
            this.id = id;
        }
    
        public String getItemName() {
            return itemName;
        }
    
        public void setItemName(String itemName) {
            this.itemName = itemName;
        }
    
    
        public Integer getItemNum() {
            return itemNum;
        }
    
        public void setItemNum(Integer itemNum) {
            this.itemNum = itemNum;
        }
    }

@Entity
    @Table(name="Bases")
    public class Base {
        @Id
        @GenericGenerator(strategy="uuid",name="uuid")
        @GeneratedValue(generator = "uuid")
        private String id;
    
        private String baseName;
    
        @JsonManagedReference
        @OneToMany(mappedBy = "base",cascade = CascadeType.ALL,fetch = FetchType.EAGER)
        private Set<Item> items = new HashSet<Item>();
    
    
        public Base(){
    
        }
    
    
        public String getId() {
            return id;
        }
    
        public void setId(String id) {
            this.id = id;
        }
    
        public Set<Item> getItems() {
            return items;
        }
    
        public void setItems(Set<Item> items) {
            this.items = items;
        }
    
        public String getBaseName() {
            return baseName;
        }
    
        public void setBaseName(String baseName) {
            this.baseName = baseName;
        }
    }

参考博客：

[jackson中的@JsonBackReference和@JsonManagedReference，以及@JsonIgnore][jackson_JsonBackReference_JsonManagedReference_JsonIgnore]

[jackson_JsonBackReference_JsonManagedReference_JsonIgnore]: https://blog.csdn.net/qq_35357001/article/details/55505659