JSON Date Format

When we pass formatted date through JSON the conversion won't to same as we required. So we need to use @JsonSerialize annotation to get out customized date format. Below example shows with and without @JsonSerialize annotation and its output. Here we used Spring rest to demonstrate with response type as JSON.

Employee model class which contains date field.

Employee.java

import java.util.Date;

import com.fasterxml.jackson.databind.annotation.JsonSerialize;

public class Employee {

 private int id;
 private String empName;
 private Date doj;
 
 public int getId() {
  return id;
 }
 public void setId(int id) {
  this.id = id;
 }
 public String getEmpName() {
  return empName;
 }
 public void setEmpName(String empName) {
  this.empName = empName;
 }
 public Date getDoj() {
  return doj;
 }
 
 public void setDoj(Date doj) {
  this.doj = doj;
 } 
}

Spring rest controller class.
MyController.java

import java.util.Date;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.models.Employee;

@RestController
public class MyController {

 @RequestMapping(value="/getemp", method=RequestMethod.GET, headers="Accept=application/json")
 public ResponseEntity<Employee> getEmpDetails(){
  
  Employee emp = new Employee();
  emp.setId(1);
  emp.setEmpName("Steve");
  emp.setDoj(new Date());
  
  return new ResponseEntity<Employee>(emp, HttpStatus.OK);
 }
}

OUTPUT:

IN above example we see that DOJ date conversion to default date format is wrong. So we need to set @JsonSerialize annotation to get our date conversion correctly as like below example.

JSON custom date formatting class
CustomDateSerializer.java

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

public class CustomDateSerializer extends JsonSerializer<Date> {

 @Override
    public void serialize(Date date, JsonGenerator jGen, SerializerProvider arg2) throws 
        IOException, JsonProcessingException {      

        SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss");
        String fDate = sdf.format(date);

        jGen.writeString(fDate);
    }
}

Employee model class with @JsonSerialize annotation. Just add below given annotation before "doj" setter method.
Employee.java

@JsonSerialize(using = CustomDateSerializer.class)
 public void setDoj(Date doj) {
  this.doj = doj;
 } 

OUTPUT: