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Questions tagged [gson]

Gson is Google's open-source library for serializing and deserializing Java objects to/from JSON.

Gson is Google's open-source library for serializing and deserializing Java objects to/from JSON.

The Gson project is hosted at and available for download from https://github.com/google/gson and licensed using the Apache License 2.0

Latest release: 2.8.6 released on Oct 4, 2019

Project Links

  • Gson API: Javadocs for the current Gson release
  • Gson guide: This guide contains examples on how to use Gson in your code.
  • Gson Roadmap: Details on upcoming releases

Alternatives

Alternative Java-to-JSON binding solutions with similar APIs include FastJSON, Jackson, and svenson. Yet more Java-to-JSON libraries are listed at json.org.

Performance

The latest performance benchmarks for these and other JSON serialization and deserialization solutions for Java are available at https://github.com/eishay/jvm-serializers/wiki.

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Can you avoid Gson converting "<" and ">" into unicode escape sequences?

I noticed that Gson converts the string "<" into an unicode escape sequence in JSON output. Can you avoid this somehow, or do characters like "<" and ">" always have to be escaped in JSON? Consider this example which prints {"s":"\u003c"}; I'd want…
Jonik
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Gson ignoring map entries with value=null

Gson gson = new Gson(); Map map = new HashMap(); map.put("a", 1); map.put("b", null); System.out.println(gson.toJson(map)); //prints {"a":1} How do I get it to include all entries?
m2o
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How to use TypeToken + generics with Gson in Kotlin

I'm unable to get a List of generic type from a custom class (Turns): val turnsType = TypeToken>() {}.type val turns = Gson().fromJson(pref.turns, turnsType) it said: cannot access '' it is 'public /*package*/' in 'TypeToken'
Juan Saravia
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Using Enums while parsing JSON with GSON

This is related to a previous question that I asked here earlier JSON parsing using Gson I am trying to parse the same JSON, but now I have changed my classes a little bit. { "lower": 20, "upper": 40, "delimiter": " ", "scope":…
Sachin Kulkarni
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Kotlin Data Class from Json using GSON

I have Java POJO class like this: class Topic { @SerializedName("id") long id; @SerializedName("name") String name; } and I have a Kotlin data class Like this data class Topic(val id: Long, val name: String) How to provide the…
erluxman
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How to deserialize a list using GSON or another JSON library in Java?

I can serialize a List
Valter Silva
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What is the basic purpose of @SerializedName annotation in Android using Gson

What is the basic purpose of @SerializedName annotation in Android using Gson? Give me some different examples. I can't understand the main purpose of using it.
Muhammad Ali
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Multiple GSON @SerializedName per field?

Is there any way in Gson to map multiple JSON fields to a single Java object member variable? Let's say I have a Java class... public class MyClass { String id; String name; } I want to use this single class with two different services.…
Gus
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Parsing JSON array into java.util.List with Gson

I have a JsonObject named "mapping" with the following content: { "client": "127.0.0.1", "servers": [ "8.8.8.8", "8.8.4.4", "156.154.70.1", "156.154.71.1" ] } I know I can get the array "servers"…
Abel Callejo
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Convert JSON style properties names to Java CamelCase names with GSON

I'm using GSON to convert JSON data I get to a Java object. It works pretty well in all my tests. The problem is that our real objects have some properties named like is_online. GSON only maps them if they are named totally equal, it would be nice…
Janusz
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Gson library in Android Studio

Can someone give me step by step guide to add the Gson library to an Android project? I tried the JSON built-in library but that seems to be a bit tedious right now. I saw a couple of examples based on Gson, and that seems really easy.
Venky
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Get nested JSON object with GSON using retrofit

I'm consuming an API from my android app, and all the JSON responses are like this: { 'status': 'OK', 'reason': 'Everything was fine', 'content': { < some data here > } The problem is that all my POJOs have a status, reason…
mikelar
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Using GSON to parse a JSON array

I have a JSON file like this: [ { "number": "3", "title": "hello_world", }, { "number": "2", "title": "hello_world", } ] Before when files had a root element I would use: Wrapper w =…
Eduardo
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Polymorphism with gson

I have a problem deserializing a json string with Gson. I receive an array of commands. The command can be start, stop , some other type of command. Naturally I have polymorphism, and start/stop command inherit from command. How can I serialize…
Sophie
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How to convert a String to JsonObject using gson library

Please advice how to convert a String to JsonObject using gson library. What I unsuccesfully do: String string = "abcde"; Gson gson = new Gson(); JsonObject json = new JsonObject(); json = gson.toJson(string); // Can't convert String to…
Eugene
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