Payload Transformation: XML to Object
Part 3 of this Payload Transformations series will show you how to transform an XML payload to a Java Object with Java classes and object transformers.
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This is Part 3 of our Payload Transformation series; if you would like to check out the previous article about payload transformation, you can find it here.
When constructing a Mule flow, we often encounter many different types of payloads, such as XML, JSON, and Object.
In this article, we are going to tackle handling XML payloads- more specifically, transforming an XML payload into a Java object.
We are going to use the following payload as an example:
Using XML to Object
Let's create our flow.
We create an HTTP inbound endpoint and an XML to Object transformer component.
Our flow should look like this:
Try running the program. If you notice, the flow will throw an error. The XML payload does not automatically get converted into a Java Object.
Create a Java Class
In order to successfully transform our XML payload, we must first define a Java class.
We will name our Java class "Student."
Our Java class should look like this:
The variable names indicated in our Java class should match the XML elements' name. Note, the names are case sensitive.
Configure The XML to Object Transformer
After defining our Java class, we will then configure our XML to Object Transformer Component.
Let's define our driver class (e.g. Xpp3Driver).
In the Advanced Tab, we will add an alias. The name of the alias should match the root element's name in our XML payload. In this case, we are going to use the name "Student."
The Class Name should contain the name of the package myschool.model.Student together with the name of our java class, Student.
Once we have configured our XML to Object transformer component, let's try running our program. We have successfully transformed the XML payload into Student object.
Taking It Further
What if you would like to transform a more complex XML?
Now, we have a new element called "subjects" with a list of subject elements.
Redefining the Java Class
In order for us to transform the XML payload successfully, we must first redefine the Java class "Student" that we created earlier.
Add the following code in Student.java:
private List subjects;
Remember, our variable name should match our XML payload's element name, subjects.
We also need to generate GET and SET methods for our new variable.
Since we don't have a Subject class, we need to create a Java class named "Subject."
Subject.java should look like this:
Reconfigure XML to Object Transformer
Once the Java classes are ready, we then reconfigure our transformer component.
In the Advanced tab, add another alias named subject under the Class Name myschool.model.Subject:
Let's try running our new program.
The XML payload has been successfully converted into our new Java object!
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