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Updated on 2025-04-05

Summary of the differences between different versions of JSONObject in Java

In Java, the implementation and behavior of the JSONObject class may vary depending on the version of the JSON library used. The following are several common JSON libraries and their main differences between different versions, focusing on the changes and development of the JSONObject class.

1. FastJSON

Version History

FastJSON ：

  • This is the earliest version, widely used in Alibaba internal projects and other Java projects.
  • Provides basic JSON parsing and generation functions, supporting serialization and deserialization of multiple data types.
  • Built-in support for loop references, and infinite recursion can be avoided through configuration.
  • Good performance, especially when dealing with large amounts of data.
  • Security Issues: There were multiple security issues in earlier versions, and it is recommended to use them with caution, especially when dealing with untrusted inputs.

FastJSON ：

  • FastJSON is a major upgrade to the release, fixing many known security issues, and introducing new features and optimizations.
  • Performance improvement: Improves overall performance by optimizing internal algorithms and reducing unnecessary object creation.
  • Security enhancement: Add more security checks and reduce potential security risks.
  • API Improvements: Some APIs have been simplified to make them easier to use. For example, the parseObject() method is now more intelligent and can automatically infer the target type.
  • Modular design: Modularize some functions to facilitate users to selectively introduce dependencies as needed.
  • Compatibility: Try to maintain compatibility with the version, but in some cases the code may need to be adjusted.

Example (FastJSON):

import .;

JSONObject jsonObject = new JSONObject();
("name", "Alice");
("age", 30);
String jsonString = ();
(jsonString); // Output: {"name":"Alice","age":30}

2. Jackson

Version History

Jackson ：

  • Jackson is an early version that provides basic JSON parsing and generation capabilities.
  • Supports streaming APIs for handling large files or performance-sensitive applications.
  • The API is relatively complex, but powerful, suitable for handling complex JSON structures.
  • Thread-safe: ObjectMapper instances are thread-safe and suitable for multi-threaded environments.

Jackson ：

  • Jackson is a major upgrade to the release, fixing many known issues and introducing new features and optimizations.
  • Performance improvement: Improves overall performance by optimizing internal algorithms and reducing unnecessary object creation.
  • API Improvements: Some APIs have been simplified to make them easier to use. For example, ObjectMapper now supports more configuration options and extension mechanisms.
  • Modular design: Modularize some functions to facilitate users to selectively introduce dependencies as needed.
  • New features: New features of JsonNode and ObjectNode, such as traverse(), at(), etc., are introduced to facilitate handling of complex JSON structures.
  • Security enhancement: Add more security checks and reduce potential security risks.
  • Compatibility: Try to maintain compatibility with the version, but in some cases the code may need to be adjusted.

Example (Jackson):

import ;
import ;

ObjectMapper objectMapper = new ObjectMapper();
ObjectNode jsonObject = ();
("name", "Alice");
("age", 30);
String jsonString = ();
(jsonString); // Output: {"name":"Alice","age":30}

3. Gson

Version History

Gson ：

  • Gson is the most commonly used version at present, providing basic JSON parsing and generation functions.
  • Supports generics, which can easily convert JSON strings into Java objects.
  • Provides @SerializedName annotation to facilitate customizing JSON field names.
  • Performance optimization: Improves overall performance by optimizing internal algorithms and reducing unnecessary object creation.
  • API Improvements: Some APIs have been simplified to make them easier to use. For example, the fromJson() and toJson() methods are now more intelligent and can automatically infer target types.
  • Modular design: Modularize some functions to facilitate users to selectively introduce dependencies as needed.
  • New features: TypeAdapter and TypeAdapterFactory are introduced to facilitate users to customize serialization and deserialization logic.
  • Security enhancement: Add more security checks and reduce potential security risks.
  • Compatibility: Try to maintain compatibility with earlier versions, but in some cases the code may need to be tweaked.

Example (Gson):

import ;

JsonObject jsonObject = new JsonObject();
("name", "Alice");
("age", 30);
String jsonString = ();
(jsonString); // Output: {"name":"Alice","age":30}

4. 

Version History

2020+：

  • is a lightweight JSON library that is widely used in Android development and other Java projects.
  • A JSONObject class is provided to represent JSON objects and supports basic JSON operations.
  • Performance optimization: Improves overall performance by optimizing internal algorithms and reducing unnecessary object creation.
  • API Improvements: Some APIs have been simplified to make them easier to use. For example, the put() method is now more intelligent and can automatically infer data types.
  • New features: The opt() series method has been introduced to facilitate processing of missing or invalid JSON fields.
  • Security enhancement: Add more security checks and reduce potential security risks.
  • Compatibility: Try to maintain compatibility with earlier versions, but in some cases the code may need to be tweaked.

Example (2020+):

import ;

JSONObject jsonObject = new JSONObject();
try {
    ("name", "Alice");
    ("age", 30);
    String jsonString = ();
    (jsonString); // Output: {"name":"Alice","age":30}} catch (Exception e) {
    ();
}

5. Version selection suggestions

FastJSON：

  • Recommended version: FastJSON
  • Reason: The release fixes many security issues in the release and introduces new features and optimizations, with significant performance and security improvements.

Jackson：

  • Recommended version: Jackson
  • Reason: The version provides better performance, richer APIs and stronger security, suitable for handling complex JSON structures and high performance needs.

Gson：

  • Recommended version: Gson
  • Reason: The version provides better performance, cleaner APIs and stronger security, suitable for small projects and rapid development.

：

  • Recommended version: 2020+
  • Reason: The 2020+ version provides better performance, cleaner APIs and stronger security, suitable for small projects and Android development.

6. Summary

There are some differences between the implementations of different versions of JSONObject, which are mainly reflected in performance, functionality, API design and security. Which version to choose depends on your specific needs and project characteristics:

  • If you need high performance and rich features and the project has high security requirements, it is recommended to use Jackson or FastJSON. Not only do they perform well, they also provide a large number of configuration options and expansion mechanisms, suitable for large projects and complex scenarios.
  • If you are pursuing simplicity and use, and the project is small, you can choose Gson or 2020+. Their API is very intuitive and suitable for fast development and small projects.
  • If you work in the Alibaba ecosystem, or are already using FastJSON, you can choose FastJSON. But it needs to be aware of its security issues, especially when dealing with untrusted inputs.
  • If you are in Android development, 2020+ is the default choice because it is already included in the Android SDK without the need to introduce additional dependencies.

This is the end of this article about the difference between different versions of JSONObject in Java. For more related contents of JSONObject, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!