Jackson JSON - Using @JsonSerialize and @JsonDeserialize with Converter for custom conversion

[Last Updated: Aug 11, 2020]

In this example we will learn how to do custom deserialization and serialization using @JsonSerialize and @JsonDeserialize annotations.

We will use @JsonSerialize#converter and @JsonDeserialize#converter attributes. These attributes require com.fasterxml.jackson.databind.util.Converter class type. We will, of course, also need to provide the custom converter implementations.


In this example we are going to convert LocalDateTime to a formatted string and vice-versa.

Java Object

package com.logicbig.example;

import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import java.time.LocalDateTime;

public class CurrencyRate {
  private String pair;
  private double rate;
  @JsonSerialize(converter = LocalDateTimeToStringConverter.class)
  @JsonDeserialize(converter = StringToLocalDatetimeConverter.class)
  private LocalDateTime lastUpdated;

Custom Converters

package com.logicbig.example;

import com.fasterxml.jackson.databind.util.StdConverter;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;

public class LocalDateTimeToStringConverter extends StdConverter<LocalDateTime, String> {
  static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM);

  public String convert(LocalDateTime value) {
      return value.format(DATE_FORMATTER);
package com.logicbig.example;

import com.fasterxml.jackson.databind.util.StdConverter;
import java.time.LocalDateTime;

public class StringToLocalDatetimeConverter extends StdConverter<String, LocalDateTime> {

  public LocalDateTime convert(String value) {
      return LocalDateTime.parse(value, LocalDateTimeToStringConverter.DATE_FORMATTER);

Main class

public class ExampleMain {
  public static void main(String[] args) throws IOException {
      System.out.println("-- Java object to JSON --");
      CurrencyRate cr = new CurrencyRate();
      System.out.println("Java object: " + cr);

      ObjectMapper om = new ObjectMapper();
      String s2 = om.writeValueAsString(cr);
      System.out.println("JSON string: "+s2);

      System.out.println("-- JSON to Java object --");
      CurrencyRate cr2 = om.readValue(s2, CurrencyRate.class);
      System.out.println("Java Object: "+cr2);
-- Java object to JSON --
Java object: CurrencyRate{pair='USD/JPY', rate=109.15, lastUpdated=2018-06-01T15:03:01.596670}
JSON string: {"pair":"USD/JPY","rate":109.15,"lastUpdated":"Jun 1, 2018, 3:03:01 PM"}
-- JSON to Java object --
Java Object: CurrencyRate{pair='USD/JPY', rate=109.15, lastUpdated=2018-06-01T15:03:01}

Example Project

Dependencies and Technologies Used:

  • jackson-databind 2.9.5: General data-binding functionality for Jackson: works on core streaming API.
  • JDK 10
  • Maven 3.3.9

@JsonSerialize and @JsonDeserialize with Converter Example Select All Download
  • jackson-serialize-deserialize-converter
    • src
      • main
        • java
          • com
            • logicbig
              • example

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