How to parse JSON using Moshi

This article shows how to parse JSON using Moshi.

Table of contents:

• 1. Download Moshi
• 2. Parse JSON using Moshi
• 3. Parse JSON Array using Moshi
• 4. Convert Java Object to JSON String
• 5. Download Source Code
• 6. References

P.S Tested with Moshi 1.15.1

1. Download Moshi

Declare moshi in the pom.xml, and it will automatically pull in other necessary dependencies.

    <dependency>
        <groupId>com.squareup.moshi</groupId>
        <artifactId>moshi</artifactId>
        <version>1.15.1</version>
    </dependency>

$ mvn dependency:tree

[INFO] \- com.squareup.moshi:moshi:jar:1.15.1:compile
[INFO]    +- com.squareup.okio:okio-jvm:jar:3.7.0:compile
[INFO]    |  \- org.jetbrains.kotlin:kotlin-stdlib:jar:1.9.21:compile
[INFO]    |     \- org.jetbrains:annotations:jar:13.0:compile
[INFO]    \- org.jetbrains.kotlin:kotlin-stdlib-jdk8:jar:1.8.21:compile
[INFO]       \- org.jetbrains.kotlin:kotlin-stdlib-jdk7:jar:1.8.21:compile

2. Parse JSON using Moshi

A simple JSON string.

  {
    "name": "mkyong",
    "age": 20
  }

The following example uses Moshi to convert a JSON string to a Java object Person.

package com.mkyong.json.model;

public class Person {

    private String name;
    private int age;

    //getters, setters, constructors
}

package com.mkyong.json.moshi;

import com.mkyong.json.model.Person;
import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;

public class JsonToObjectExample {

    public static void main(String[] args) {

        Moshi moshi = new Moshi.Builder().build();
        JsonAdapter<Person> jsonAdapter = moshi.adapter(Person.class);

        String json = "{\"name\":\"mkyong\",\"age\":42}";
        try {
            // JSON to Java object
            Person person = jsonAdapter.fromJson(json);
            System.out.println(person);
        } catch (Exception e) {
            System.err.println("Error parsing JSON: " + e.getMessage());
        }

    }

}

Output

Person{name='mkyong', age=42}

3. Parse JSON Array using Moshi

Array of JSON.

  [
    {
      "name": "mkyong",
      "age": 42
    },
    {
      "name": "ah pig",
      "age": 20
    }
  ]

The following example uses Moshi to convert an array of JSON objects to a list of Java object List<Person>.

package com.mkyong.json.moshi;

import com.mkyong.json.model.Person;
import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;
import com.squareup.moshi.Types;

import java.lang.reflect.Type;
import java.util.List;

public class JsonArrayToObjectExample {

    public static void main(String[] args) {

        Moshi moshi = new Moshi.Builder().build();

        // List<Person>
        Type type = Types.newParameterizedType(List.class, Person.class);

        JsonAdapter<List<Person>> adapter = moshi.adapter(type);

        // json array
        String json = "[{\"name\":\"mkyong\", \"age\":42}, {\"name\":\"ah pig\", \"age\":20}]";
        try {

            // convert json array to list of objects
            List<Person> list = adapter.fromJson(json);
            if (list != null) {
                for (Person person : list) {
                    System.out.println(person);
                }
            }

            // convert list of objects to json array
            // String json2 = adapter.toJson(list);

            // Output: [{"age":42,"name":"mkyong"},{"age":20,"name":"ah pig"}]
            // System.out.println(json2);


        } catch (Exception e) {
            System.err.println("Error parsing JSON: " + e.getMessage());
        }

    }
}

output

Person{name='mkyong', age=42}
Person{name='ah pig', age=20}

4. Convert Java Object to JSON String

The following example uses Moshi to convert a Java object Person to a JSON String and print it to the console.

package com.mkyong.json.moshi;

import com.mkyong.json.model.Person;
import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;

public class ObjectToJsonExample {

    public static void main(String[] args) {

        Moshi moshi = new Moshi.Builder().build();
        JsonAdapter<Person> jsonAdapter = moshi.adapter(Person.class);

        Person person = new Person("mkyong", 42);

        try {
            String json = jsonAdapter.toJson(person);
            System.out.println(json);

        } catch (Exception e) {
            System.err.println("Error parsing JSON: " + e.getMessage());
        }

    }

}

Output

{"age":42,"name":"mkyong"}

5. Download Source Code

6. References

• Moshi Github
• Parse JSON string with Jackson
• Parse JSON Array with Jackson
• Convert Java Objects to JSON with Jackson

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