Gson is a Java Library which is used to convert Java Objects to JSON strings and back. Gson library provides `toJson()` and `fromJson()` methods using which users can serialize /deserialize Java objects to and back from JSON Strings. ## Installation #### Maven ```xml com.google.code.gson gson 2.8.5 ``` #### Gradle ```groovy // https://mvnrepository.com/artifact/com.google.code.gson/gson compile group: 'com.google.code.gson', name: 'gson', version: '2.8.5' ``` ## Java Object to JSON String ```java import java.util.Arrays; import java.util.HashMap; import java.util.Map; import com.google.gson.Gson; public class GsonObjectToJSONExample { public static void main(String[] args) { Gson gson = new Gson(); Map javaObject = new HashMap<>(); javaObject.put("aNumber", 1); javaObject.put("aString", "foo"); javaObject.put("aBoolean", true); javaObject.put("aList", Arrays.asList("red", "green", "blue")); String jsonString = gson.toJson(javaObject); System.out.println(jsonString); } } ``` ### Output: ```json {"aNumber":1,"aBoolean":true,"aString":"foo","aList":["red","green","blue"]} ``` ## JSON String to Java Object ```java import java.util.Map; import com.google.gson.Gson; public class GsonJsonToObjectExample { public static void main(String[] args) { Gson gson = new Gson(); String jsonString = "{\"aNumber\":1,\"aBoolean\":true,\"aString\":\"foo\",\"aList\":[\"red\",\"green\",\"blue\"]}"; Map javaObject = gson.fromJson(jsonString, Map.class); System.out.println("aList: " + javaObject.get("aList")); System.out.println("aNumber: " + javaObject.get("aNumber")); } } ``` ### Output: ```sh aList: [red, green, blue] aNumber: 1.0 ```

Gson (Java Library) Cheatsheet

0

Installation

Maven

Gradle

Java Object to JSON String

Output:

JSON String to Java Object

Output:

OneCompiler.com

Languages

More