Dung (Donny) Nguyen

Senior Software Engineer

Controller and RestController

In the Spring framework, @Controller and @RestController are used to define controllers, but they serve different purposes and are used in different scenarios:

`@Controller`

Purpose: Used to define a standard web controller in Spring MVC.
Response Handling: Typically returns a view (like an HTML page) using a view resolver.
Usage: Suitable for web applications where the response is usually an HTML page.

Example:

@Controller
@RequestMapping("/users")
public class UserController {
    @GetMapping("/{id}")
    public String displayUserInfo(@PathVariable Long id) {
        // logic to get user info
        return "userView"; // returns the view name
    }
}

`@RestController`

Purpose: A specialized version of @Controller used to create RESTful web services.
Response Handling: Combines @Controller and @ResponseBody, so it returns data directly (like JSON or XML) instead of a view.
Usage: Ideal for REST APIs where the response is typically JSON or XML.

Example:

@RestController
@RequestMapping("/users")
public class UserRestController {
    @GetMapping("/{id}")
    public User getUserById(@PathVariable Long id) {
        // logic to get user info
        return new User(id, "John Doe"); // returns the user object as JSON
    }
}

In summary, @Controller is used for traditional web applications that return views, while @RestController is used for RESTful web services that return data directly in formats like JSON or XML.

References: