Spring Boot集成Reactor事件处理框架的简单示例

1. Reactor简介

Reactor 是 Spring 社区发布的基于事件驱动的异步框架，不仅解耦了程序之间的强调用关系，而且有效提升了系统的多线程并发处理能力。

2. Spring Boot集成Reactor的pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.springframework</groupId>
    <artifactId>spring-boot-reactor</artifactId>
    <version>0.1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>0.5.0.M2</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectreactor</groupId>
            <artifactId>reactor-spring</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
        </dependency>
    </dependencies>

    <properties>
        <start-class>org.springboot.reactor.example.App</start-class>
    </properties>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-snapshots2</id>
            <url>http://repo.springsource.org/libs-snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-release</id>
            <url>http://repo.springsource.org/libs-release</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <url>http://repo.springsource.org/libs-snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>
</project>

3. Spring Boot的主程序

package org.springboot.reactor.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class App{
    public static void main( String[] args ) {
    	SpringApplication.run(App.class, args);
    }
}

4. 领域数据User

package org.springboot.reactor.example;

public class User {

	String firstName;

	String lastName;

	String address;

	String city;

}

5. 实例化Reactor Bean,这里采用内部 Bean 方式实现，其他方式也可以，保证能够供其它类注入即可

package org.springboot.reactor.example;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import reactor.core.Environment;
import reactor.core.Reactor;
import reactor.core.spec.Reactors;

@Configuration
public class Configure {
	@Bean
	Environment env() {
		return new Environment();
	}

	@Bean
    Reactor createReactor(Environment env) {
        return Reactors.reactor()
                .env(env)
                .dispatcher(Environment.THREAD_POOL)
                .get();
    }
}

6. Controller层用于通过reactor.notify发送事件

package org.springboot.reactor.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import reactor.core.Reactor;
import reactor.event.Event;

@RestController
@RequestMapping("/api")
public class ReactorController {

	@Autowired
	private Reactor reactor;

	@RequestMapping("/test")
	public void test() throws InterruptedException{
		User user = new User();
		user.firstName = "Chetan";
		user.lastName = "Birajdar";
		user.address = "410 S Hauser";
		user.city = "Los Angeles";
		reactor.notify("eventHandler", Event.wrap(user));
		System.out.println("y0, I sent something for you!!");
	}
}

7. 事件的监听器，以便于接收发送的事件并处理。需要实现 Consumer<Event<T>> 接口，其中 T 是处理程序接收的数据类型，要根据具体业务设置

package org.springboot.reactor.example;

import org.springframework.stereotype.Service;

import reactor.event.Event;
import reactor.function.Consumer;

@Service
public class AppListener implements Consumer<Event<User>>{

	public void accept(Event<User> event) {
		System.out.println("Received user object with "
				+ "first name:"
				+ event.getData().firstName
				+ ", last name:"
				+ event.getData().lastName
				+ ", address:"
				+ event.getData().address
				+ ", city:"
				+ event.getData().city
				+ "");
	}
}

8. ReactorService，实现InitializingBean接口，以便将发送的事件绑定到指定的监听器

package org.springboot.reactor.example;

import static reactor.event.selector.Selectors.$;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import reactor.core.Reactor;

@Service
public class ReactorService implements InitializingBean{

	@Autowired
	private Reactor reactor;

	@Autowired
	private AppListener appListener;

	@Override
	public void afterPropertiesSet() throws Exception {
		reactor.on($("eventHandler"), appListener);
	}
}

9. 当启动应用时，调用/api/test接口，向eventHandler的topic发送User事件，监听器即可接收到相关的事件并处理