While you are encouraged to use JAX-RS annotation for defining REST endpoints, Quarkus provides a compatibility layer for Spring Web in the form of the spring-web
extension.
This guide explains how your Quarkus application can leverage the well known Spring Web annotations to define RESTful services.
Prerequisites
To complete this guide, you need:
-
less than 15 minutes
-
an IDE
-
JDK 1.8+ installed with
JAVA_HOME
configured appropriately -
Apache Maven 3.5.3+
Solution
We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.
Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git
, or download an archive.
The solution is located in the using-spring-web
directory.
Creating the Maven project
First, we need a new project. Create a new project with the following command:
mvn io.quarkus:quarkus-maven-plugin:0.21.0:create \
-DprojectGroupId=org.acme \
-DprojectArtifactId=using-spring-web \
-DclassName="org.acme.spring.web.GreetingController" \
-Dpath="/greeting" \
-Dextensions="spring-web"
This command generates a Maven project with a REST endpoint and imports the spring-web
extension.
Writing the GreetingController
Before writing the GreetingController
, let’s first create a Greeting
class that will be used as a response from the controller.
Furthermore let’s create a Spring bean called GreetingBean
that will be used by the controller.
package org.acme.spring.web;
public class Greeting {
private final String message;
public Greeting(String message) {
this.message = message;
}
public String getMessage() {
return message;
}
}
package org.acme.spring.web;
import org.springframework.stereotype.Service;
@Service
public class GreetingBean {
public String greet(String input) {
return "HELLO " + input.toUpperCase() + "!";
}
}
The Quarkus Maven plugin automatically generated a src/main/java/org/acme/spring/web/GreetingController.java
file.
However since we are going to be using Spring Web annotations to define our REST endpoint (instead of the JAX-RS ones used by default), we need to change
the GreetingController
to have the following content:
package org.acme.spring.web;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.PathVariable;
@RestController
@RequestMapping("/greeting")
public class GreetingController {
private final GreetingBean greetingBean;
public GreetingController(GreetingBean greetingBean) {
this.greetingBean = greetingBean;
}
@GetMapping("/{name}")
public Greeting hello(@PathVariable(name = "name") String name) {
return new Greeting(greetingBean.greet(name));
}
}
Update the test
We also need to update the functional test to reflect the changes made to the endpoint. Change its content to:
package org.acme.spring.web;
import io.quarkus.test.junit.QuarkusTest;
import org.junit.jupiter.api.Test;
import static io.restassured.RestAssured.given;
import static org.hamcrest.CoreMatchers.is;
@QuarkusTest
public class GreetingControllerTest {
@Test
public void testGreeting() {
given()
.when().get("/greeting/world")
.then()
.statusCode(200)
.body("message", is("HELLO WORLD!"));
}
}
Package and run the application
Run the application with: ./mvnw compile quarkus:dev
.
Open your browser to http://localhost:8080/greeting/world.
The result should be: {"message": "HELLO WORLD!"}
.
Run the application as a native executable
You can of course create a native image using the instructions of the Building a native executable guide.
Supported Spring Web functionalities
Quarkus currently supports a subset of the functionalities that Spring Web provides. More specifically Quarkus supports the REST related features of Spring Web
(think of @RestController
instead of @Controller
).
Annotations
The table below summarizes the supported annotations:
Name | Comments |
---|---|
@RestController |
|
@RequestMapping |
|
@GetMapping |
|
@PostMapping |
|
@PutMapping |
|
@DeleteMapping |
|
@PatchMapping |
|
@RequestParam |
|
@RequestHeader |
|
@MatrixVariable |
|
@PathVariable |
|
@CookieValue |
|
@RequestBody |
|
@ResponseStatus |
|
@ExceptionHandler |
Can only be used in a @RestControllerAdvice class, not on a per-controller basis |
@RestControllerAdvice |
Only the @ExceptionHandler capability is supported |
Important Technical Note
Please note that the Spring support in Quarkus does not start a Spring Application Context nor are any Spring infrastructure classes run.
Spring classes and annotations are only used for reading metadata and / or are used as user code method return types or parameter types.
What that means for end users, is that adding arbitrary Spring libraries to the classpath will not be taken into account. Moreover Spring infrastructure
things like org.springframework.beans.factory.config.BeanPostProcessor
will not be executed.