Moshi - How to convert Java object to JSON and JSON to Java object

In this section, we will show you how to convert Java object to JSON and JSON to Java object with Moshi.

Note

Moshi is a modern JSON library for Java that will give us powerful JSON serialization and deserialization in our code with little effort.

Note

JSON (JavaScript Object Notation) is a lightweight format that is used for data interchanging.

JSON is built on two structures: 

• A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array. 
• An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.

1. Download Moshi

<dependency>
   <groupId>com.squareup.moshi</groupId>
   <artifactId>moshi</artifactId>
   <version>1.13.0</version>
</dependency>
<dependency>
   <groupId>com.squareup.moshi</groupId>
   <artifactId>moshi-adapters</artifactId>
   <version>1.13.0</version>
</dependency>

2. JSON to Java Objects

A User POJO, later uses this for conversion.

User.java

public class User {

    private String name;
    private String email;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

Main.java

public class Main {

    public static void main(String[] args) throws IOException {


        String json = "{\"name\":\"sibin\", " +
                       "\"email\":\"sibin@gmail.in\"}";

        Moshi moshi = new Moshi.Builder().build();
        JsonAdapter<User> jsonAdapter = moshi.adapter(User.class);
        User user = jsonAdapter.fromJson(json);
        System.out.println(user);
    }
}

Console Output:

User{name='sibin', email='sibin@gmail.in'}

3. Java Objects to JSON

Main.java

import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;
import java.io.IOException;

public class Main {

    public static void main(String[] args) throws IOException {


        User user = new User();
        user.setName("sibin");
        user.setEmail("sibin@gmail.in");

        Moshi moshi = new Moshi.Builder().build();
        JsonAdapter<User> jsonAdapter = moshi.adapter(User.class);
        String json = jsonAdapter.toJson(user);
        System.out.println(json);
    }
}

Console Output:

{"email":"sibin@gmail.in","name":"sibin"}

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