Spring Boot REST API - Returning Response in XML Format

Introduction

In this guide, we will learn how to return a response in XML format from a Spring Boot REST API. By default, Spring Boot returns responses in JSON, but we can configure it to return XML by following a few simple steps. This is particularly useful when integrating with systems that require XML responses, such as legacy applications or third-party services.

Why Use XML in REST APIs?

• Interoperability: Many older systems and enterprise applications still rely on XML for data exchange.
• Structured Data: XML provides a well-structured format that is widely used in web services (SOAP-based services).
• Customization: XML allows for defining custom schemas and DTDs, making data validation more flexible.

Steps to Implement XML Response in Spring Boot

1️⃣ Add Required Dependency

Spring Boot uses Jackson for JSON serialization and deserialization. To enable XML support, we need to include jackson-dataformat-xml dependency in pom.xml:

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

This dependency enables Jackson to convert Java objects into XML format automatically.

2️⃣ Create a Model Class (DTO) for XML Response

We need a model class (DTO) that represents the response data. Annotate it with @XmlRootElement and @XmlAccessorType to enable XML conversion.

package com.example.demo.dto;

import jakarta.xml.bind.annotation.XmlElement;
import jakarta.xml.bind.annotation.XmlRootElement;
import jakarta.xml.bind.annotation.XmlAccessorType;
import jakarta.xml.bind.annotation.XmlAccessType;

@XmlRootElement(name = "User")
@XmlAccessorType(XmlAccessType.FIELD)
public class UserResponse {

    @XmlElement
    private String name;

    @XmlElement
    private int age;

    @XmlElement
    private String email;

    // Default Constructor
    public UserResponse() {}

    // Parameterized Constructor
    public UserResponse(String name, int age, String email) {
        this.name = name;
        this.age = age;
        this.email = email;
    }

    // Getters and Setters
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }

    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }

    public String getEmail() { return email; }
    public void setEmail(String email) { this.email = email; }
}

3️⃣ Create a REST Controller

Next, we create a Spring Boot REST Controller that returns the response in XML format. We use produces = MediaType.APPLICATION_XML_VALUE to specify XML response type.

package com.example.demo.controller;

import com.example.demo.dto.UserResponse;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api")
public class UserController {

    @GetMapping(value = "/user", produces = MediaType.APPLICATION_XML_VALUE)
    public UserResponse getUser() {
        return new UserResponse("Ayush", 25, "[e-mail]");
    }
}

4️⃣ Create Main Spring Boot Application Class

The main class is needed to start the Spring Boot application.

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

5️⃣ Run the Application and Test the API

Start the Spring Boot application, then send a GET request using Postman, Browser, or Curl:

GET http://localhost:8080/api/user

6️⃣ Expected XML Response Output

When the API is called, it returns the response in XML format as shown below:

<User>
    <name>Ayush</name>
    <age>25</age>
    <email>[e-mail]</email>
</User>

Troubleshooting Common Issues

✅ Error: XML Response Not Showing?

• Ensure that the jackson-dataformat-xml dependency is added.
• Check if produces = MediaType.APPLICATION_XML_VALUE is correctly set in the controller.
• Use Postman and check the Accept header; set it to application/xml.

✅ XML Response Showing as JSON?

• Spring Boot defaults to JSON; explicitly request XML by setting the Accept header to application/xml.
• Make sure the model class is correctly annotated with @XmlRootElement and @XmlAccessorType.

Summary

✅ Added Jackson XML dependency to support XML serialization.

✅ Created a DTO class with @XmlRootElement to define the XML structure.

✅ Developed a REST API that returns XML response using produces = MediaType.APPLICATION_XML_VALUE.

✅ Ran and tested the API to verify XML response output.

Conclusion

Using XML in Spring Boot REST APIs is straightforward and useful when working with applications that require XML data exchange. With proper configuration, we can seamlessly switch between JSON and XML responses depending on the client’s request.