This article shows you what @Controller and @RestController are and their differences.
Table of contents:
- 1. Spring @Controller annotation
- 2. Spring @RestController annotation
- 3. Download Source Code
- 4. References
1. Spring @Controller annotation
Spring 2.5 introduced the @Controller as the web controller for the MVC architecture. Spring 3.0 introduced the @ResponseBody to return the method’s return type directly into the HTTP response body. We can combine both @Controller and @ResponseBody to quickly create RESTful web services.
For example:
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
public class HelloController {
@RequestMapping(value="/hello1", method= RequestMethod.GET)
@ResponseBody
String hello1() {
return "Hello World! - 1";
}
@RequestMapping(value="/hello2", method= RequestMethod.GET)
@ResponseBody
String hello2() {
return "Hello World! - 2";
}
@RequestMapping(value="/hello3", method= RequestMethod.GET)
@ResponseBody
String hello3() {
return "Hello World! - 3";
}
}
2. Spring @RestController annotation
Since the RESTful architecture is getting popular, and a class can easily contain a lot of @ResponseBody methods, generating many duplicated codes. So, Spring 4.0 introduced @RestController to simplify the creation of RESTful web services.
Review the @RestController source code; the @RestController itself is also annotated with @Controller and @ResponseBody.
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Controller
@ResponseBody
public @interface RestController {
@AliasFor(annotation = Controller.class)
String value() default "";
}
Note
The @RestController does nothing but act like a shortcut for @Controller and @ResponseBody; it saves the developer from annotating @ResponseBody on all the RESTful handler methods.
With @RestController, now we can rewrite the above @Controller example like this:
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
@RequestMapping(value="/hello1", method= RequestMethod.GET)
String hello1() {
return "Hello World! - 1";
}
@RequestMapping(value="/hello2", method= RequestMethod.GET)
String hello2() {
return "Hello World! - 2";
}
@RequestMapping(value="/hello3", method= RequestMethod.GET)
String hello3() {
return "Hello World! - 3";
}
}
3. Download Source Code
$ git clone https://github.com/mkyong/spring-boot.git
