Spring Reactive应用示例

1. pom依赖

<properties>
   <spring-boot.version>2.4.3</spring-boot.version>
   <project.version>2.3.0</project.version>
</properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <dependency>
            <groupId>io.cloudevents</groupId>
            <artifactId>cloudevents-spring</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>io.cloudevents</groupId>
            <artifactId>cloudevents-http-basic</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>io.cloudevents</groupId>
            <artifactId>cloudevents-json-jackson</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
        </dependency>
    </dependencies>

2. 添加启动类，注册序列化、反序列化配置类

package io.cloudevents.examples.spring;

import io.cloudevents.spring.webflux.CloudEventHttpMessageReader;
import io.cloudevents.spring.webflux.CloudEventHttpMessageWriter;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.codec.CodecCustomizer;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.codec.CodecConfigurer;

@SpringBootApplication
public class DemoApplication {

	public static void main(String[] args) throws Exception {
		SpringApplication.run(DemoApplication.class, args);
	}

	@Configuration
	public static class CloudEventHandlerConfiguration implements CodecCustomizer {

		@Override
		public void customize(CodecConfigurer configurer) {
			configurer.customCodecs().register(new CloudEventHttpMessageReader());
			configurer.customCodecs().register(new CloudEventHttpMessageWriter());
		}

	}

}

3. 监听端口资源配置

在resource目录下的application.properties文件中配置监听端口号等信息。

server.port=8080

4. 提供接口服务

创建一个MainResource类，提供一个简单的接口服务

package io.cloudevents.examples.spring;

import io.cloudevents.CloudEvent;
import io.cloudevents.core.builder.CloudEventBuilder;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import reactor.core.publisher.Mono;

import java.net.URI;
import java.util.UUID;

@Slf4j
@RestController
public class MainResource {

    @PostMapping("/event-invoke")
    // Use CloudEvent API and manual type conversion of request and response body
    public Mono<CloudEvent> event(@RequestBody Mono<CloudEvent> body) {
        log.info("receive event");
        return body.map(event -> CloudEventBuilder.from(event) //
                .withId(UUID.randomUUID().toString()) //
                .withSource(URI.create("https://spring.io/foos")) //
                .withType("io.spring.event.Foo") //
                .withData(event.getData().toBytes()) //
                .build());
    }

    @GetMapping("/health")
    //It doesn't use the `CloudEvent` data type directly, but instead models the request and response body
    public ResponseEntity<String> health() {
        log.info("receive health check");
        return ResponseEntity.ok().body("Hands up");
    }
}

其中event-invoke处理事件函数请求逻辑；health用于程序本身健康检测。您可以自定义其他path进行业务处理。

5. Maven编译打包

在pom.xml文件中添加spring-boot-maven-plugin 插件

 <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>${spring-boot.version}</version>
                <configuration>
                  <mainClass>io.cloudevents.examples.spring.DemoApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

使用下面命令将代码和及其依赖打包成可执行的jar包，编译后的jar包位于项目文件内的target目录内。

maven package

编译好的jar包需用zip工具进行压缩，用于后续控制台的代码包上传。

6. Gradle编译打包

build.gradle配置文件如下：

plugins {
    id 'org.springframework.boot' version '2.4.3'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
}

group = 'com.example'
version = '1.0-SNAPSHOT'
sourceCompatibility = '1.8'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-webflux:2.4.3'
    implementation 'io.cloudevents:cloudevents-spring:2.3.0'
    implementation 'io.cloudevents:cloudevents-http-basic:2.3.0'
    implementation 'io.cloudevents:cloudevents-json-jackson:2.3.0'
    compileOnly 'org.projectlombok:lombok'
    annotationProcessor 'org.projectlombok:lombok'
    testImplementation 'org.springframework.boot:spring-boot-starter-test:2.4.3'
}

description = 'cloudevents-spring-reactive-example'

在项目的根目录下执行下面命令打包

gradle bootJar

编译后的jar包位于项目文件内的build/libs目录下。
如果显示编译失败，请根据输出的编译错误信息调整代码。