Custom response headers in Spring Boot - Mini Project: Build & Apply

Custom Response Headers in Spring Boot

📖 Scenario: You are building a simple Spring Boot web service that returns a greeting message. You want to add a custom response header to the HTTP response to provide extra information to the client.

🎯 Goal: Create a Spring Boot controller that returns a greeting message and includes a custom response header named X-Custom-Header with the value MyHeaderValue.

📋 What You'll Learn

Create a Spring Boot REST controller class named GreetingController.

Add a GET endpoint at /greet that returns a String greeting message.

Add a custom response header X-Custom-Header with the value MyHeaderValue to the HTTP response.

💡 Why This Matters

🌍 Real World

Custom response headers are often used to send extra information like security tokens, version info, or metadata from a server to a client in web applications.

💼 Career

Knowing how to add custom headers in Spring Boot is important for backend developers to control HTTP responses and improve API communication.

1

Create the GreetingController class

Create a public class named GreetingController annotated with @RestController.

Spring Boot

@RestController
public class GreetingController {
    // Your code here
}

Need a hint?

Use @RestController annotation above the class declaration.

2

Add a GET endpoint method

Inside GreetingController, add a public method named greet annotated with @GetMapping("/greet") that returns the String "Hello, World!".

Spring Boot

import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.GetMapping;

@RestController
public class GreetingController {
    // Your code here
}

Need a hint?

Use @GetMapping("/greet") to map the method to the GET request path.

3

Add HttpServletResponse parameter

Modify the greet method to accept a parameter of type HttpServletResponse named response.

Spring Boot

import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.GetMapping;
import jakarta.servlet.http.HttpServletResponse;

@RestController
public class GreetingController {
    @GetMapping("/greet")
    public String greet(HttpServletResponse response) {
        // Your code here
        return "Hello, World!";
    }
}

Need a hint?

Add HttpServletResponse response as a parameter to the greet method.

4

Set the custom response header

Inside the greet method, use the response object to add a header named X-Custom-Header with the value MyHeaderValue before returning the greeting string.

Spring Boot

import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.GetMapping;
import jakarta.servlet.http.HttpServletResponse;

@RestController
public class GreetingController {
    @GetMapping("/greet")
    public String greet(HttpServletResponse response) {
        // Add custom header here
        return "Hello, World!";
    }
}

Need a hint?

Use response.addHeader("X-Custom-Header", "MyHeaderValue") to add the header.