How to Seamlessly Handle XML Requests and Responses in Spring Boot

In previous Spring Boot tutorials we only covered handling HTML and JSON requests and responses. This article shows how to quickly bind XML requests to objects in a controller and return objects as XML.

Implementation Principle: Message Converter

Spring Boot processes HTTP requests using Spring MVC, which relies on the concept of a message converter to transform various request formats into objects. Spring MVC defines the HttpMessageConverter interface that abstracts type support, read/write capabilities, and conversion operations.

public interface HttpMessageConverter<T> {
    boolean canRead(Class<?> clazz, @Nullable MediaType mediaType);
    boolean canWrite(Class<?> clazz, @Nullable MediaType mediaType);
    List<MediaType> getSupportedMediaTypes();
    T read(Class<? extends T> clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException;
    void write(T t, @Nullable MediaType contentType, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException;
}

To support XML, Spring MVC provides the MappingJackson2XmlHttpMessageConverter implementation, which is automatically registered when the jackson-dataformat-xml dependency is present.

Extension Implementation

Step 1: Add XML Message Converter

In a traditional Spring application you can configure the converter manually:

@Configuration
public class MessageConverterConfig1 extends WebMvcConfigurerAdapter {
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        Jackson2ObjectMapperBuilder builder = Jackson2ObjectMapperBuilder.xml();
        builder.indentOutput(true);
        converters.add(new MappingJackson2XmlHttpMessageConverter(builder.build()));
    }
}

In a Spring Boot application you only need to add the jackson-dataformat-xml dependency, and the converter is auto‑configured:

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
</dependency>

Step 2: Define Object‑XML Mapping

Create a Java class that corresponds to the XML structure, using Lombok for boilerplate code and Jackson XML annotations for mapping:

@Data
@NoArgsConstructor
@AllArgsConstructor
@JacksonXmlRootElement(localName = "User")
public class User {
    @JacksonXmlProperty(localName = "name")
    private String name;
    @JacksonXmlProperty(localName = "age")
    private Integer age;
}

The Lombok annotations generate getters, setters, and constructors, while @JacksonXmlRootElement and @JacksonXmlProperty define how the fields map to XML elements.

An example XML that matches the User class:

<User>
    <name>aaaa</name>
    <age>10</age>
</User>

Step 3: Create Controller to Receive and Return XML

Define a REST controller that consumes and produces XML:

@Controller
public class UserController {
    @PostMapping(value = "/user", consumes = MediaType.APPLICATION_XML_VALUE, produces = MediaType.APPLICATION_XML_VALUE)
    @ResponseBody
    public User create(@RequestBody User user) {
        user.setName("didispace.com : " + user.getName());
        user.setAge(user.getAge() + 100);
        return user;
    }
}

Run the Spring Boot application and use a tool such as Postman to POST the XML payload; the service will return the processed XML response.