How to Deserialize XML Attributes to a Map String,String with JacksonXML

Discover how to efficiently use JacksonXML to deserialize unpredicted XML attributes into a `Map String,String `. Step-by-step guide included!
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: With JacksonXML I'd like to deserialize unpredetermined list of elements to the Map String,String . What kind of annotations I can use for that?

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Deserializing XML Attributes to a Map with JacksonXML

When working with XML data in Java, you may encounter scenarios where the structure of the XML is not predetermined, making it challenging to map the data directly to a defined class structure. A common case is having an XML element with multiple attributes whose names can vary. In this guide, we will explore how to effectively handle such a situation using JacksonXML to deserialize these attributes into a Map<String,String>.

The Challenge

Consider an XML element like the following:

[[See Video to Reveal this Text or Code Snippet]]

In this XML snippet, the attributes do not adhere to a fixed set of names. Therefore, we need a flexible solution that allows us to capture these attributes dynamically into a map structure. The goal is to translate these XML elements into a Java object containing a Map<String,String> to hold the attributes.

Solution Overview

To achieve this, we can leverage the power of Jackson's annotations, specifically the @ JsonAnySetter annotation. This annotation allows us to capture any additional properties not defined in the Java class and store them in a map.

Step-by-Step Implementation

Let’s break down the implementation process into clear steps:

1. Create the Java Class

First, we need to define a class to represent our XML element. In this case, we'll call it MyElement. This class will contain a map attribute to hold the dynamic attributes.

[[See Video to Reveal this Text or Code Snippet]]

In the MyElement class:

We define a Map<String, String> to store the XML attributes.

The addAttribute method is annotated with @ JsonAnySetter. This enables Jackson to invoke this method for any attribute present in the XML that doesn't correspond to a property of the class.

2. Deserialize the XML

After defining our class, we can proceed to deserialize the XML string into an instance of MyElement. We will utilize the XmlMapper from Jackson.

[[See Video to Reveal this Text or Code Snippet]]

A Closer Look at the Code:

We declare our XML string containing attributes.

We create an instance of XmlMapper, which is responsible for parsing the XML.

The readValue method reads the XML and maps it to our MyElement class.

3. Accessing the Attributes

After deserialization, the attributes map within the MyElement object will contain all the attributes extracted from the XML element. You can then access and use this map as needed in your application.

Conclusion

Using JacksonXML with the @ JsonAnySetter annotation provides a powerful way to handle unpredictable XML attributes effectively. This approach allows you to easily deserialize XML elements into Java objects while preserving the flexibility required for varying attribute names.

Now, you can seamlessly integrate this solution into your Java application whenever you encounter dynamic XML data. Happy coding!