Creating REST Controller in Spring.

In previous article we learned about creating a new Spring boot application using Spring Initializr.

In this article we will learn how to create REST controller in our application.

Step 1:

Open the application which we have created in our previous article.

Follow the below steps:

1. Create a new folder controller inside the package com.techopaths.springboot.demo
2. Right click on springboot folder -> new -> folder.
3. Type controller as name.

We have successfully create a new package com.techopaths.springboot.demo.controller

Step 2:

Now we will create a new Java class

Follow the below steps:

1. Create a new classRestControllerinside the package com.techopaths.springboot.demo.controller
2. Right-click on controller folder -> new -> class, if the class is not there then click on other and type class.
3. Type RestController as name.
4. Click on the finish.

Step 3:

We have successfully created our Java class and we will write below code.

package com.techopaths.springboot.controller;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;

@org.springframework.web.bind.annotation.RestController
public class RestController {

	@GetMapping("/message")
	public ResponseEntity<String> getMessage() {
		return new ResponseEntity<>("Hello world", HttpStatus.OK);
	}
}

@RestController: Spring 4.0 introduced @RestController, a specialized version of the controller which is a convenience annotation that does nothing more than adding the @Controller and @ResponseBody annotations. By annotating the controller class with @RestController annotation, you no longer need to add @ResponseBody to all the request mapping methods. The @ResponseBody annotation is active by default.

This annotation indicates that a particular class serves the role of a controller. The dispatcher scans such annotated classes for mapped methods and detects @RequestMapping annotations.

@GetMapping: This is used to create a mapping to function with a path. The request type here is GET. Specifically, @GetMapping is a composed annotation that acts as a shortcut for @RequestMapping(method = RequestMethod.GET).

Now run the application.

Enter http://localhost:8080/message in your browser.

You will see the message.

We have successfully created the Rest Controller.

To download this application click here.

Stay tuned for more articles 🙂