Quickest way to convert XML to JSON in Java

java

xml-to-json

jackson-library

org-json-library

byAnton Shumikhin·Jan 24, 2025

Convert XML to JSON in Java using Jackson library swiftly. XmlMapper parses the XML, and ObjectMapper converts it to JSON:

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;

String xmlInput = "<root><value>Convert me!</value></root>";
XmlMapper xmlMapper = new XmlMapper();
JsonNode rootNode = xmlMapper.readTree(xmlInput.getBytes()); // Jackson is reading the XML, kind of like how we read a memorable Reddit joke

ObjectMapper jsonMapper = new ObjectMapper();
String jsonOutput = jsonMapper.writeValueAsString(rootNode);
System.out.println(jsonOutput);  // Outputs: {"value":"Convert me!"}, you did it!

This code snippet first reads the XML】,【then constructs a JSON node, and finally transforms it into a JSON string with Jackson's built-in functions.

Processing XML to JSON: the basics

A deep dive into the Jackson library's core will help to fully understand the conversion from **XML to JSON. Yet there's still an alternative library, org.json, worth a mention - particularly for its simplicity and accessibility.

Integration of org.json library

Add the following Maven dependency to your project to make use of org.json:

<dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20210307</version>
</dependency>

Make use of org.json and convert XML to JSON swiftly using XML.toJSONObject:

import org.json.JSONObject;
import org.json.XML;

public class XML2JSON {
    public static void main(String[] args) {
        String xmlString = "<root><test attribute='show'>Hello World!</test></root>";
        JSONObject jsonObject = XML.toJSONObject(xmlString); // Pepsi Challenge: can your JSON beat this?
        String jsonPrettyPrint = jsonObject.toString(4); // Prettify JSON by the 'indentFactor' of 4
        System.out.println(jsonPrettyPrint);
    }
}

Conquering arrays and complex cases

Working with XML arrays may feel like solving Rubik's Cube while skydiving. But worry not, here's how to win:

JSONObject jsonObject = XML.toJSONObject(xmlString, true); // Here, 'true' turn the tide for XML arrays

If you seek a complete hands-on practice, consider the XMLToJsonConverterUsingJAVA GitHub project. Just clone, open in Eclipse, and enjoy the ride!

Optimizing larger data processing

For those dealing with massive data from web services or network streams, tools like BufferedReader and InputStreamReader can elegantly handle XML responses:

BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
// BufferedReader: because sometimes you need a buffer from all the data overload

Make sure to verify the status code and check that the inputStream is not null before processing - it's healthier than a bowl of salad!

Overcoming common hurdles

Here are some hit-the-brakes moments that could surface during XML to JSON conversion and how to handle them:

Wrestling with XML special characters

Escape special characters in XML inputs to prevent possible JSON structure chaos. Lucky for you, most libraries such as Jackson and org.json got your back, handling escape sequences for you!

Respecting JSON array representation

When XML structure should translate to JSON arrays, tagging elements is a non-negotiable step. Accurate array hints or design ensure arrays get the treatment they deserve in JSON.

Boosting JSON object to String performance

In environments where memory is as precious as a bottle of water in a desert, writing a JSON object directly to an outputStream can be a lifesaver. Need to get this done? Jackson's writeValue(outputStream, value) is your best buddy.

Winning strategies for smooth conversions

Be the Michael Jordan of XML to JSON conversion with these practices:

Validate XML: Ensure your XML is well-formed before conversion.
Test with varied payloads: Emulate all potential edge cases.
Library update checks: Stay current with performance enhancements and bug fixes.
Configure mapping settings: Set appropriate settings for arrays and attributes.

Implementing these practices will make your conversion journey effortless and triumphant.

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