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Quarkus Extension for Spring Web API

While users are encouraged to use Jakarta REST (formerly known as JAX-RS) annotations for defining REST endpoints, Quarkus provides a compatibility layer for Spring Web in the form of the spring-web extension.

This guide explains how a Quarkus application can leverage the well known Spring Web annotations to define RESTful services.

先决条件

要完成这个指南,你需要:

完成这个指南,你需要:

  • 大概15分钟

  • 编辑器

  • JDK 17+ installed with JAVA_HOME configured appropriately

  • Apache Maven 3.9.9

  • 如果你愿意的话,还可以选择使用Quarkus CLI

  • 如果你想构建原生可执行程序,可以选择安装Mandrel或者GraalVM,并正确配置(或者使用Docker在容器中进行构建)

解决方案

我们建议您按照下一节的说明逐步创建应用程序。然而,您可以直接转到已完成的示例。

克隆 Git 仓库: git clone https://github.com/quarkusio/quarkus-quickstarts.git ,或下载一个 存档

The solution is located in the spring-web-quickstart directory.

创建Maven项目

首先,我们需要一个新的工程项目。用以下命令创建一个新项目:

CLI
quarkus create app org.acme:spring-web-quickstart \
    --extension='spring-web,rest-jackson' \
    --no-code
cd spring-web-quickstart

创建Grade项目,请添加 --gradle 或者 --gradle-kotlin-dsl 参数。

For more information about how to install and use the Quarkus CLI, see the Quarkus CLI guide.

Maven
mvn io.quarkus.platform:quarkus-maven-plugin:3.17.2:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=spring-web-quickstart \
    -Dextensions='spring-web,rest-jackson' \
    -DnoCode
cd spring-web-quickstart

创建Grade项目,请添加 -DbuildTool=gradle 或者 -DbuildTool=gradle-kotlin-dsl 参数。

For Windows users:

  • If using cmd, (don’t use backward slash \ and put everything on the same line)

  • If using Powershell, wrap -D parameters in double quotes e.g. "-DprojectArtifactId=spring-web-quickstart"

This command generates a project which imports the spring-web extension.

If you already have your Quarkus project configured, you can add the spring-web extension to your project by running the following command in your project base directory:

CLI
quarkus extension add spring-web,rest-jackson
Maven
./mvnw quarkus:add-extension -Dextensions='spring-web,rest-jackson'
Gradle
./gradlew addExtension --extensions='spring-web,rest-jackson'

这会将以下内容添加到你的构建文件中:

pom.xml
<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-spring-web</artifactId>
</dependency>
<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-rest-jackson</artifactId>
</dependency>
build.gradle
implementation("io.quarkus:quarkus-spring-web")
implementation("io.quarkus:quarkus-rest-jackson")

quarkus-spring-web needs to be complemented with either quarkus-rest-jackson or quarkus-resteasy-jackson in order to work.

GreetingController

Create the src/main/java/org/acme/spring/web/GreetingController.java file, a controller with the Spring Web annotations to define our REST endpoint, as follows:

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;

@RestController
@RequestMapping("/greeting")
public class GreetingController {

    @GetMapping
    public String hello() {
        return "hello";
    }
}

GreetingControllerTest

Note that a test for the controller has been created as well:

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 testHelloEndpoint() {
        given()
          .when().get("/greeting")
          .then()
             .statusCode(200)
             .body(is("hello"));
    }

}

打包并运行该应用程序

使用以下命令运行该应用程序:

CLI
quarkus dev
Maven
./mvnw quarkus:dev
Gradle
./gradlew --console=plain quarkusDev

在你的浏览器中打开 http://localhost:8080/greeting 网页。

The result should be: {"message": "hello"}.

以本地可执行文件的方式运行该应用程序

You can generate the native executable with:

CLI
quarkus build --native
Maven
./mvnw install -Dnative
Gradle
./gradlew build -Dquarkus.native.enabled=true

Going further with an endpoint returning JSON

The GreetingController above was an example of a very simple endpoint. In many cases however it is required to return JSON content. The following example illustrates how that could be achieved using a Spring RestController:

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

@RestController
@RequestMapping("/greeting")
public class GreetingController {

    @GetMapping("/{name}")
    public Greeting hello(@PathVariable(name = "name") String name) {
        return new Greeting("hello " + name);
    }

    public static class Greeting {
        private final String message;

        public Greeting(String message) {
            this.message = message;
        }

        public String getMessage(){
            return message;
        }
    }
}

The corresponding test could look like:

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 testHelloEndpoint() {
        given()
          .when().get("/greeting/quarkus")
          .then()
            .statusCode(200)
            .body("message", is("hello quarkus"));
    }

}

It should be noted that when using the Spring Web support in Quarkus, Jackson is automatically added to the classpath and properly set up.

Adding OpenAPI and Swagger-UI

You can add support for OpenAPI and Swagger-UI by using the quarkus-smallrye-openapi extension.

Add the extension by running this command:

./mvnw quarkus:add-extension -Dextensions="io.quarkus:quarkus-smallrye-openapi"

这将在你的 pom.xml 中添加以下内容:

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-smallrye-openapi</artifactId>
</dependency>

This is enough to generate a basic OpenAPI schema document from your REST Endpoints:

curl http://localhost:8080/q/openapi

You will see the generated OpenAPI schema document:

---
openapi: 3.0.1
info:
  title: Generated API
  version: "1.0"
paths:
  /greeting:
    get:
      responses:
        "200":
          description: OK
          content:
            '*/*':
              schema:
                type: string
  /greeting/{name}:
    get:
      parameters:
      - name: name
        in: path
        required: true
        schema:
          type: string
      responses:
        "200":
          description: OK
          content:
            'application/json':
              schema:
                $ref: '#/components/schemas/Greeting'
components:
  schemas:
    Greeting:
      type: object
      properties:
        message:
          type: string

Adding MicroProfile OpenAPI Annotations

You can use MicroProfile OpenAPI to better document your schema, example, adding the following to the class level of the GreetingController:

@OpenAPIDefinition(
    info = @Info(
        title="Greeting API",
        version = "1.0.1",
        contact = @Contact(
            name = "Greeting API Support",
            url = "http://exampleurl.com/contact",
            email = "techsupport@example.com"),
        license = @License(
            name = "Apache 2.0",
            url = "https://www.apache.org/licenses/LICENSE-2.0.html"))
)

And describe your endpoints like this:

@Tag(name = "Hello", description = "Just say hello")
@GetMapping(produces=MediaType.TEXT_PLAIN_VALUE)
public String hello() {
    return "hello";
}

@GetMapping(value = "/{name}", produces=MediaType.APPLICATION_JSON_VALUE)
@Tag(name = "Hello to someone", description = "Just say hello to someone")
public Greeting hello(@PathVariable(name = "name") String name) {
    return new Greeting("hello " + name);
}

will generate this OpenAPI schema:

---
openapi: 3.0.1
info:
  title: Greeting API
  contact:
    name: Greeting API Support
    url: http://exampleurl.com/contact
    email: techsupport@example.com
  license:
    name: Apache 2.0
    url: https://www.apache.org/licenses/LICENSE-2.0.html
  version: 1.0.1
tags:
- name: Hello
  description: Just say hello
- name: Hello to someone
  description: Just say hello to someone
paths:
  /greeting:
    get:
      tags:
      - Hello
      responses:
        "200":
          description: OK
          content:
            '*/*':
              schema:
                type: string
  /greeting/{name}:
    get:
      tags:
      - Hello to someone
      parameters:
      - name: name
        in: path
        required: true
        schema:
          type: string
      responses:
        "200":
          description: OK
          content:
            '*/*':
              schema:
                $ref: '#/components/schemas/Greeting'
components:
  schemas:
    Greeting:
      type: object
      properties:
        message:
          type: string

Using Swagger UI

Swagger UI is included by default when running in Dev or Test mode, and can optionally be added to Prod mode. See the Swagger UI Guide for more details.

Navigate to localhost:8080/q/swagger-ui/ and you will see the Swagger UI screen:

Swagger UI

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:

Table 1. Supported Spring Web annotation
名称 备注

@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

Controller method return types

The following method return types are supported:

  • Primitive types

  • String (which will be used as a literal, no Spring MVC view support is provided)

  • POJO classes which will be serialized via JSON

  • org.springframework.http.ResponseEntity

Controller method parameter types

In addition to the method parameters that can be annotated with the appropriate Spring Web annotations from the previous table, jakarta.servlet.http.HttpServletRequest and jakarta.servlet.http.HttpServletResponse are also supported. For this to function however, users need to add the quarkus-undertow dependency.

Exception handler method return types

The following method return types are supported:

  • org.springframework.http.ResponseEntity

  • java.util.Map

Other return types mentioned in the Spring ExceptionHandler javadoc are not supported.

Exception handler method parameter types

The following parameter types are supported, in arbitrary order:

  • An exception argument: declared as a general Exception or as a more specific exception. This also serves as a mapping hint if the annotation itself does not narrow the exception types through its value().

  • Request and/or response objects (typically from the Servlet API). You may choose any specific request/response type, e.g. ServletRequest / HttpServletRequest. To use Servlet API, the quarkus-undertow dependency needs to be added.

Other parameter types mentioned in the Spring ExceptionHandler javadoc are not supported.

重要技术说明

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 will not have any effect. Moreover, Spring infrastructure classes (like org.springframework.beans.factory.config.BeanPostProcessor for example) will not be executed.

Conversion Table

The following table shows how Spring Web annotations can be converted to Jakarta REST annotations.

Spring Jakarta REST 备注

@RestController

There is no equivalent in Jakarta REST. Annotating a class with @Path suffices

@RequestMapping(path="/api")

@Path("/api")

@RequestMapping(consumes="application/json")

@Consumes("application/json")

@RequestMapping(produces="application/json")

@Produces("application/json")

@RequestParam

@QueryParam

@PathVariable

@PathParam

@RequestBody

No equivalent in Jakarta REST. Method parameters corresponding to the body of the request are handled in Jakarta REST without requiring any annotation

@RestControllerAdvice

No equivalent in Jakarta REST

@ResponseStatus

No equivalent in Jakarta REST

@ExceptionHandler

No equivalent annotation in Jakarta REST. Exceptions are handled by implementing jakarta.ws.rs.ext.ExceptionMapper

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