Java Jackson XML Ignore

1. Introduction

Ignoring specific XML elements during the deserialization process can be particularly useful when we only want to map a subset of the XML content to our Java POJO. Jackson's XML module provides a convenient way to achieve this by using annotations like @JsonIgnoreProperties and @JsonIgnore. In this post, we will explore how to ignore specific XML elements using the Jackson library.

2. Program Steps

1. Include necessary Jackson XML dependencies in your project.

2. Create a Java POJO and annotate it with Jackson annotations to specify which XML elements to ignore.

3. Use XmlMapper to deserialize the XML content.

4. Display the resulting Java object.

3. Code Program

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;

public class JacksonXmlIgnoreExample {

    public static class Product {
        public String name;

        @JsonIgnore
        public String price;

        @Override
        public String toString() {
            return "Product{name='" + name + "'}";
        }
    }

    public static void main(String[] args) {
        try {
            // Sample XML content
            String xmlString = "<product><name>Laptop</name><price>1200.5</price></product>";

            // Create XmlMapper instance
            XmlMapper xmlMapper = new XmlMapper();

            // Deserialize XML string to Product object
            Product product = xmlMapper.readValue(xmlString, Product.class);

            System.out.println(product);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Output:

Product{name='Laptop'}

4. Step By Step Explanation

1. We have XML content that represents a product with a name and a price.

2. In our Product Java class, we annotated the price field with @JsonIgnore. This indicates to Jackson that this field should be ignored during the deserialization process.

3. We use the XmlMapper class to deserialize the XML content into our Product class.

4. The readValue method of XmlMapper is invoked, passing in the XML string and the Product class type.

5. The resulting product object is printed, and as we can see, only the name attribute is populated, while the price is ignored.

By leveraging Jackson annotations, we can easily control which XML elements are considered during the deserialization process, giving us greater flexibility in handling XML content.