GSON - Serialize and Deserialize Primitives Types

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In this quick article, we will discuss how to use GSON to serialize or deserialize any primitive type into JSON representation.

GSON Maven Dependency

To use Gson with Maven2/3, we can use the Gson version available in Maven Central by adding the following dependency:

<dependencies>
    <dependency>
      <groupId>com.google.code.gson</groupId>
      <artifactId>gson</artifactId>
      <version>2.8.5</version>
      <scope>compile</scope>
    </dependency>
</dependencies>

Serialize Primitives Types

We can serialize any primitive type into their JSON representation.

// Serialization
Gson gson = new Gson();

// Serialization of integer
System.out.println(gson.toJson(1));

// Serialization of String
System.out.println(gson.toJson("abcd"));

// Serialization of Long
System.out.println(gson.toJson(new Long(10)));

// Serialization of int array
int[] values = { 1 };
System.out.println(gson.toJson(values));

// Serialization of Double
System.out.println(gson.toJson(new Double(10.0d)));

// Serialization of Character
System.out.println(gson.toJson(new Character('A')));

Deserialize Primitives Types

We can deserialize the JSON String into their primitive type.

// Deserialization of int
System.out.println(gson.fromJson("1", int.class));

// Deserialization of Integer
System.out.println(gson.fromJson("1", Integer.class));

// Deserialization of Long
System.out.println(gson.fromJson("1", Long.class));

// Deserialization of Boolean
System.out.println(gson.fromJson("false", Boolean.class));

// Deserialization of String
System.out.println(gson.fromJson("\"abc\"", String.class));

// Deserialization of String[]
System.out.println(gson.fromJson("[\"abc\"]", String[].class));

// Deserialization of Character
System.out.println(gson.fromJson("A", Character.class));

Complete Java program to Serialize and Deserialize Primitives Types using GSON

The complete program for your reference:

package net.javaguides.gson;

import com.google.gson.Gson;

public class GSONPrimitiveExamples {
    public static void main(String[] args) {
        // Serialization
        Gson gson = new Gson();

        // Serialization of integer
        System.out.println(gson.toJson(1));

        // Serialization of String
        System.out.println(gson.toJson("abcd"));

        // Serialization of Long
        System.out.println(gson.toJson(new Long(10)));

        // Serialization of int array
        int[] values = {
            1
        };
        System.out.println(gson.toJson(values));

        // Serialization of Double
        System.out.println(gson.toJson(new Double(10.0 d)));

        // Serialization of Character
        System.out.println(gson.toJson(new Character('A')));

        // Deserialization of int
        System.out.println(gson.fromJson("1", int.class));

        // Deserialization of Integer
        System.out.println(gson.fromJson("1", Integer.class));

        // Deserialization of Long
        System.out.println(gson.fromJson("1", Long.class));

        // Deserialization of Boolean
        System.out.println(gson.fromJson("false", Boolean.class));

        // Deserialization of String
        System.out.println(gson.fromJson("\"abc\"", String.class));

        // Deserialization of String[]
        System.out.println(gson.fromJson("[\"abc\"]", String[].class));

        // Deserialization of Character
        System.out.println(gson.fromJson("A", Character.class));
    }
}

Output:

1
"abcd"
10
[1]
10.0
"A"
1
1
1
false
abc
[Ljava.lang.String;@2b71fc7e
A

Reference

GSON User Guide

GSON Java DOC

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Google GSON Tutorial

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