当对象在 jackson 库中具有父子关系时，将使用@jsonidentityinfo注释。 @jsonidentityinfo 注解 用于在序列化和反序列化过程中指示对象身份。 objectidgenerators.propertygenerator 是一个抽象占位符类，用于表示要使用的对象标识符来自 pojo 属性的情况。
语法@target(value={annotation_type,type,field,method,parameter})@retention(value=runtime)public @interface jsonidentityinfo
示例import java.util.*;import java.io.*;import com.fasterxml.jackson.annotation.jsonidentityinfo;import com.fasterxml.jackson.annotation.objectidgenerators;import com.fasterxml.jackson.databind.objectmapper;public class jsonidentityinfotest { public static void main(string[] args) throws ioexception { objectmapper mapper = new objectmapper(); user user = new user(115, "raja", "ramesh"); address address = new address(125, "madhapur", "hyderabad", user); user.addaddress(address); string jsonstring = mapper.writerwithdefaultprettyprinter().writevalueasstring(address); system.out.println(jsonstring); }}// user class@jsonidentityinfo(generator = objectidgenerators.propertygenerator.class, property = "userid")class user { private int userid; private string firstname; private string lastname; private list<address> addresses; public user(int userid, string firstname, string lastname) { this.userid = userid; this.firstname = firstname; this.lastname = lastname; this.addresses = new arraylist<address>(); } public int getuserid() { return userid; } public string getfirstname() { return firstname; } public string getlastname() { return lastname; } public void addaddress(address address) { addresses.add(address); }}// address class@jsonidentityinfo(generator = objectidgenerators.propertygenerator.class, property = "userid")class address { private int userid; private string city; private string street; private user user; public address(int userid, string street, string city, user user) { this.userid = userid; this.street = street; this.city = city; this.user = user; } public int getuserid() { return userid; } public string getstreet() { return street; } public string getcity() { return city; } public user getuser() { return user; }}
输出{ "userid" : 125, "city" : "hyderabad", "street" : "madhapur", "user" : { "userid" : 115, "firstname" : "raja", "lastname" : "ramesh" }}
以上就是@jsonidentityinfo注解在java中使用jackson的重要性是什么？的详细内容。