Some fields not getting parsed/deserialized in JSON in Springboot

Question

I am using the below JSON to get parsed by my springboot code:

{
    "id" :123, 
    "Subject" : "English",
    "name": {
    "Firstname": "Hemant",
    "Middlename": "kumar", 
    "Lastname": "Mamod"
    }
}

But on parsing/deserializing it I am getting this in the object of Student:

Student [id=123, Subject=null, name=Name [Firstname=null, Middlename=null, Lastname=null]]

I aleady have public gettters & setters everywhere which makes every field eligible for deserialization. I am referring this - https://www.baeldung.com/jackson-field-serializable-deserializable-or-not

Below is the code snippet I am using:

Restcontroller:

    package com.example.demo;
    import java.util.*;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.http.MediaType;
    import org.springframework.web.bind.annotation.*;


    @SpringBootApplication
    @RestController
    public class Demo1Application {


    @Autowired
    Student student;
    List<Student> students = new ArrayList<>();


    @RequestMapping(value="/saveStudent", method=RequestMethod.POST,consumes=MediaType.APPLICATION_JSON_VALUE)
    public String savestudent (@RequestBody Student s1) {

        System.out.println(s1);
        return "success";
    }   


    public static void main(String[] args) {
        SpringApplication.run(Demo1Application.class, args);
        System.out.println("Hello");
    }
    }

Student Bean Class:

package com.example.demo;

import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;

@Component
public class Student {
    int id;
    String Subject;

    @Autowired
    @Qualifier("name")
    Name name;


    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getSubjects() {
        return Subject;
    }
    public void setSubject(String subject) {
        Subject = subject;
    }

    public void setName(Name name) {
        this.name = name;  
    }
    public Name getName() {  
        return name  ;
    }
@Override
public String toString() {
    return "Student [id=" + id + ", Subject=" + Subject + ", name=" + name + "]";
    }
}

Name Bean Class:

package com.example.demo;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;

@Component
@Qualifier("name")
public class Name {
    private String Firstname;
    private String Middlename;
    private String Lastname;

    public Name() {
        System.out.println("Name Object created");
    }

    public String getFirstname() {
        return Firstname;
    }
    public void setFirstname(String firstname) {
        Firstname = firstname;
    }
    public String getMiddlename() {
        return Middlename;
    }
    public void setMiddlename(String middlename) {
        Middlename = middlename;
    }
    public String getLastname() {
        return Lastname;
    }
    public void setLastname(String lastname) {
        Lastname = lastname;
    }

    public Name setfullname(String Fname, String Mname, String Lname) {
        Firstname = Fname;
        Middlename = Mname;
        Lastname = Lname;
        return this;
    }

    @Override
    public String toString() {
        return "Name [Firstname=" + Firstname + ", Middlename=" + Middlename + ", Lastname=" + Lastname + "]";
    }

}

PS -

1.) On making the private fields as public , the code is working fine. I made these fields as public - id , Subject , name, Firstname, Middlename, Lastname

2.) I already know that by adding below two in application.properties wil give me correct output: spring.jackson.deserialization.fail-on-unknown-properties=false spring.jackson.mapper.accept-case-insensitive-properties=true

I just want to know where exactly I am doing things wrong. I have public gettters & setters everywhere

Take care about java naming convention. Property names should start with lower case character — Jens
The issue might be caused by naming convention for gettters and setters in Java. Basically variable names start with lowercase letters, like firstname and getter/setter would be getFirstname()/setFirstname() but when your variables start with uppercase letter, parser can have problems with it. — Kamil
@Kamil I changed property names with lower case. Still getting same output. — ASharma7
Why is your student class annotated with @Component? Isn't it a DTO and not a Controller/Service which should not be injected anywhere? — Markus G.

James Jithin James Jithin · Accepted Answer · 2018-12-01T14:37:26

Reformat your JSON input to have camel case keys:

{
    "id" :123, 
    "subject" : "English",
    "name": {
    "firstname": "Hemant",
    "middlename": "kumar", 
    "lastname": "Mamod"
    }
}

Some fields not getting parsed/deserialized in JSON in Springboot

5 Answers