How to Make a Simple RestController in Spring Boot?

Last Updated : 12 Mar, 2025

A RestController in Spring Boot is a specialized controller that is used to develop RESTful web services. It is marked with the @RestController annotation, which combines @Controller and @ResponseBody. This ensures that the response is automatically converted into JSON or XML, eliminating the need for explicit response conversions. In this article, we will explore how to create a simple RestController in Spring Boot.

Steps to Create a Simple RestController in Spring Boot

Step 1: Setup Spring Boot Project Using Spring Initializr

Go to Spring Initializr.
Configure the project with the following details:
- Project: Maven
- Language: Java
- Spring Boot Version: 3.x (Latest Version)
- Packaging: JAR
- Java Version: 17 or later
- Dependencies: Spring Web
Click on Generate to download the project.

Step 2: Import the Project into Your IDE

Extract the zip file. Now open a suitable IDE and then go to File > New > Project from existing sources and select pom.xml. Click on import changes on prompt and wait for dependencies to load.

Note: In the Import Project for Maven window, make sure you choose the same version of JDK which you selected while creating the project.

Step 3: Create a Simple RestController

Go to src > main > java > com.geeksforgeeks.SpringBootApplication, create a new Java class with the name Controller.java and add the annotation @RestController.

Controller.java:

Java

package com.geeksforgeeks.SpringBootApplication.controller;

import org.springframework.web.bind.annotation.*;

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

    @GetMapping("/hello/{name}/{age}")
    public String sayHello(@PathVariable String name, @PathVariable int age) {
        return "Hello, " + name + "! You are " + age + " years old.";
    }
}

Explanation:

@RestController annotation marks this class as a RESTful controller.
@RequestMapping("/api") defines a base URL for all endpoints inside this controller.
@GetMapping("/hello/{name}/{age}") handles HTTP GET requests and extracts name and age from the URL.
@PathVariable annotation captures dynamic values from the request URL.
Returns a simple JSON response with a greeting message.

Step 4: Run the Spring Boot Application

Run the main class and wait for the Tomcat server to start.

Note: The default port of the Tomcat server is 8080 and can be changed in the application.properties file.

This Controller.java file is used for handling all incoming requests from the client-side.