Jackson - Convert JSON Array to Java List Object

In this post, we will see how to convert JSON array to Java List object using the Jackson library.

Dependencies

Let’s first add the following dependencies to the pom.xml:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.8</version>
</dependency>

This dependency will also transitively add the following libraries to the classpath:

• jackson-annotations-2.9.8.jar
• jackson-core-2.9.8.jar
• jackson-databind-2.9.8.jar

Always use the latest versions on the Maven central repository for Jackson databind.

Jackson - Convert JSON Array to Java List Object

We can use the ObjectMapper.readValue() method for converting a JSON text to collection object.

The following example demonstrates how to convert the JSON text to a List.

JacksonJsonToList.java

package net.javaguides.jackson;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

public class JacksonJsonToList {

    @SuppressWarnings("unchecked")
    public static void main(String[] args) throws JsonParseException, JsonMappingException, IOException {

        // Create ObjectMapper object.
        ObjectMapper mapper = new ObjectMapper();
        mapper.enable(SerializationFeature.INDENT_OUTPUT);

        String json = "[ \"C\", \"C++\", \"Java\", \"Java EE\", \"Python\", \"Scala\", \"JavaScript\" ]";

        List < String > progLangs = new ArrayList < > ();
        progLangs = mapper.readValue(json, List.class);

        for (Iterator < String > iterator = progLangs.iterator(); iterator.hasNext();) {
            String progLang = (String) iterator.next();
            System.out.println(progLang);
        }
    }
}

Output:

C
C++
Java
Java EE
Python
Scala
JavaScript

References

• https://www.javaguides.net/p/java-jackson-json-tutorial-with-examples.html