alibaba

fastjson2

Backend#Java#JSON#Serialization#Library

4,295

// summary

Fastjson2 is a high-performance JSON library for Java designed to provide an optimized and secure data processing solution for the next decade. It supports both standard JSON and the high-performance binary JSONB format while offering extensive features like JSONPath for partial parsing. The library is fully compatible with modern Java versions and includes specialized support for Kotlin, Spring, and Android environments.

// technical analysis

FASTJSON 2 is a high-performance JSON library for Java, engineered as the successor to the original FASTJSON with a focus on long-term maintainability and extreme performance. It addresses the need for a modern, secure, and versatile JSON processing tool that supports both standard text-based JSON and a high-efficiency binary format called JSONB. The library prioritizes security by disabling dangerous features like AutoType by default, while offering extensive customization through filters, annotations, and a robust JSONPath implementation for partial data extraction.

// key highlights

Delivers industry-leading performance that significantly outperforms competitors like Jackson and Gson.

Supports dual-format processing, allowing developers to work with standard JSON text or the high-performance binary JSONB protocol.

Implements SQL:2016 compatible JSONPath for efficient, partial parsing of large JSON documents without full deserialization.

Prioritizes security by disabling AutoType by default and providing a dedicated SafeMode to prevent common vulnerabilities.

Offers first-class support for modern Java features, including Records, Vector API, and seamless integration with GraalVM Native Image.

Provides idiomatic Kotlin extensions and DSL-style APIs to ensure a native development experience for Kotlin users.

// use cases

High-performance JSON and JSONB serialization and deserialization

Partial document extraction and querying using SQL:2016 compatible JSONPath

Schema validation and custom serialization logic for complex Java objects

// getting started

To begin using FASTJSON 2, add the 'com.alibaba.fastjson2:fastjson2' dependency to your Maven or Gradle project. You can then use the 'JSON.parseObject' method to convert JSON strings into Java objects or 'JSON.toJSONString' to serialize objects into JSON. For projects migrating from version 1.x, a compatibility module is available to serve as a drop-in replacement.