Spring @RestController Annotation with Example

Hey guys in this post, we will discuss spring @RestController annotation with example.

Overview

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@RestController annotation is mainly used for building restful web services using Spring MVC. It is a convenience annotation, this annotation itself annotated with @ResponseBody and @Controller annotation. The class annotated with @RestController annotation returns JSON response in all the methods.

It does not work with view technology so that the method does not return ModelAndView.

@RestController
public class CustomerController {
	
	@GetMapping("/customer")
	public Customer getCustomer () {
		//TODO
	}
}

Watch the video

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Example on @RestController

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The best way to understand @RestController is by looking at the example

Create spring boot project

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There are many different ways to create a spring boot application, you can follow the below articles to create one –

>> Create spring boot application using Spring initializer
>> Create spring boot application in Spring tool suite [STS]
>> Create spring boot application in IntelliJ IDEA

Add maven dependencies

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Open pom.xml and add the following dependencies –

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.4.3</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>in.bushansirgur</groupId>
	<artifactId>restcontrollerannotation</artifactId>
	<version>v1</version>
	<name>restcontrollerannotation</name>
	<description>Spring boot restcontroller annotation demo</description>
	<properties>
		<java.version>1.8</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

spring-boot-starter-web dependency for building web applications using Spring MVC. It uses the tomcat as the default embedded container.




spring-boot-devtools dependency for automatic reloads or live reload of applications.

Create an entity class

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Create Customer.java inside the in.bushansirgur.springboot.entity package and add the following content

package in.bushansirgur.springboot.entity;


public class Customer {
	
	private String name;
	
	private String location; 
	
	public Customer(String name, String location) {
		super();
		this.name = name;
		this.location = location;
	} 

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getLocation() {
		return location;
	}

	public void setLocation(String location) {
		this.location = location;
	}

	@Override
	public String toString() {
		return "Customer [name=" + name + ", location=" + location + "]";
	}
}

This is just a plain old java class that has private fields, setters, getters, and constructors.

Create a Rest controller

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Create CustomerController.java inside the in.bushansirgur.springboot.controller package and add the following content

package in.bushansirgur.springboot.controller;

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

import in.bushansirgur.springboot.entity.Customer;

@RestController
public class CustomerController {
	
	@GetMapping("/customer")
	public Customer getCustomer () {
		Customer c = new Customer("Bushan", "India");
		return c;
	}
}

We have annotated the class with @RestController annotation, this indicates that the class serves the role of controller and also returns JSON response from all the methods.

Run the app

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Run the application using the below maven command –

mvn spring-boot:run

Open the browser and navigate to the URL http://localhost:8080/customer

{
    "name": "Bushan",
    "location": "India"
}