java 36 lines · 8 steps

Configuring a reusable Jackson ObjectMapper

One tuned ObjectMapper drives several serialization variants for Order objects.

Explained by highlit
Intermediate serialization json builder-pattern configuration immutability
1public class OrderSerializer {
2 
3 private final ObjectMapper mapper;
4 
5 public OrderSerializer() {
6 this.mapper = JsonMapper.builder()
7 .addModule(new JavaTimeModule())
8 .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
9 .serializationInclusion(JsonInclude.Include.NON_NULL)
10 .build();
11 this.mapper.setPropertyNamingStrategy(PropertyNamingStrategies.SNAKE_CASE);
12 }
13 
14 public String toJson(Order order) throws JsonProcessingException {
15 return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(order);
16 }
17 
18 public byte[] toBytes(Order order) throws JsonProcessingException {
19 return mapper.writeValueAsBytes(order);
20 }
21 
22 public void writeTo(Path target, Order order) throws IOException {
23 try (OutputStream out = Files.newOutputStream(target)) {
24 mapper.writeValue(out, order);
25 }
26 }
27 
28 public String toJsonView(Order order) throws JsonProcessingException {
29 return mapper.writerWithView(Views.Public.class).writeValueAsString(order);
30 }
31 
32 public String toJsonArray(List<Order> orders) throws JsonProcessingException {
33 ObjectWriter writer = mapper.writerFor(new TypeReference<List<Order>>() {});
34 return writer.writeValueAsString(orders);
35 }
36}
01 / 01
STEP 01

Walkthrough

Space play ←→ step click any line
Three takeaways
  1. 1Build and configure a single ObjectMapper once, then reuse it for every serialization call.
  2. 2ObjectMapper's writer methods return specialized writers without mutating the shared mapper.
  3. 3TypeReference preserves generic type information that Java erasure would otherwise lose.

Related explainers

rust 
use serde::Deserialize;
 
#[derive(Debug, Deserialize)]
#[serde(untagged)]

Parsing flexible JSON shapes with serde

deserialization enums json
Intermediate 6 steps
typescript 
import { Module } from '@nestjs/common';
import { ConfigModule } from '@nestjs/config';
import * as Joi from 'joi';
 

Validating env config at boot in NestJS

configuration schema-validation environment-variables
Intermediate 8 steps
java 
@Component
@Converter
public class EncryptedStringConverter implements AttributeConverter<String, String> {
 

Transparent column encryption in Spring & JPA

encryption aes-gcm jpa-converter
Advanced 10 steps
rust 
use axum::{
    extract::{Path, State},
    response::sse::{Event, KeepAlive, Sse},
};

Streaming import progress with SSE in Axum

server-sent-events streams watch-channel
Advanced 7 steps
java 
package com.acme.billing.config;
 
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.ConfigurationProperties;

Feature-flagged beans with Spring @ConditionalOnProperty

feature-flags conditional-beans strategy-pattern
Intermediate 5 steps
java 
public static Map<String, String> parseCookieHeader(String header) {
    Map<String, String> cookies = new LinkedHashMap<>();
    if (header == null || header.isBlank()) {
        return cookies;

Parsing an HTTP Cookie header in Java

string-parsing http url-decoding
Intermediate 6 steps

Share this explainer

Here's the card — post it anywhere.

Configuring a reusable Jackson ObjectMapper — share card
Made with highlit — turn any snippet into a walkthrough like this in about a minute.
Explain your code