SpringCloud之Spring Cloud Stream：消息驱动

时间  2019-11-24
标签 springcloud spring cloud stream 消息 驱动 栏目 Spring 繁體版
原文   原文链接

Spring Cloud Stream 是一个构建消息驱动微服务的框架，该框架在Spring Boot的基础上整合了Spring Integrationg来链接消息代理中间件(RabbitMQ, Kafka等)，提供了个性化的自动化配置实现，并引入了发布-订阅、消费组、分区这三个核心概念。
应用程序经过input通道或者output通道来与Spring Cloud Stream中binder（绑定器）交互，经过配置来binding. 而Spring Cloud Stream的binder负责与中间件交互。java

开发工具：IntelliJ IDEA 2019.2.3web

1、服务器端spring

一、建立项目apache

IDEA中建立一个新的SpringBoot项目，名称为“spring-server”，SpringBoot版本选择2.1.10，在选择Dependencies(依赖)的界面勾选Spring Cloud Discovery -> Eureka Server。
pom.xml完整内容以下：浏览器

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>spring-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-server</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

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

</project>
View Code

二、修改配置application.yml服务器

修改端口号为8761；取消将本身信息注册到Eureka服务器，不从Eureka服务器抓取注册信息。app

server:
  port: 8761
eureka:
  client:
    register-with-eureka: false
    fetch-registry: false

三、修改启动类代码框架

增长注解@EnableEurekaServermaven

package com.example.springserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class SpringServerApplication {

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

}
View Code

2、消息生产者ide

一、建立项目
IDEA中建立一个新的SpringBoot项目，名称为“spring-producer”，SpringBoot版本选择2.1.10，在选择Dependencies(依赖)的界面勾选Web -> Spring Web，Spring Cloud Discovery -> Eureka Discovery Client。
打开pom.xml，添加依赖spring-cloud-starter-stream-rabbit，会自动引入spring-cloud-stream和spring-cloud-stream-binder。
pom.xml完整内容以下：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>spring-producer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-producer</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-stream-rabbit</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-stream-test-support</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

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

</project>
View Code

二、修改配置application.yml

pom.xml使用RabbitMQ，默认状况下，链接本地的5672端口。下面这段rabbitmq也可省略。

server:
  port: 8081
spring:
  application:
    name: spring-producer
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
rabbitmq:
  host: localhost
  post: 5672
  username: guest
  password: guest

三、编写发送服务

方法sendOrder使用@Output("myInput")注解表示建立myInput的消息通道。调用该方法后，会向myInput通道投递消息。
若是不使用参数myInput，则使用方法名做为通道名称。

package com.example.springproducer;

import org.springframework.cloud.stream.annotation.Output;
import org.springframework.messaging.SubscribableChannel;

public interface SendService {
    @Output("myInput")
    SubscribableChannel sendOrder();
}

四、修改启动类代码

加入注解@EnableBinding以开启Spring容器的绑定功能，以SendService.class为参数，Spring容器启动时，会自动绑定SendService接口中定义的通道。

package com.example.springproducer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.stream.annotation.EnableBinding;

@SpringBootApplication
@EnableEurekaClient
@EnableBinding(SendService.class)
public class SpringProducerApplication {

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

}

五、添加一个控制器类

调用SendService的发送方法，往服务器发送消息。

package com.example.springproducer;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ProducerController {

    @Autowired
    SendService sendService;

    @RequestMapping(value="/send",method= RequestMethod.GET)
    public String sendRequest(){
        //建立消息
        Message msg = MessageBuilder.withPayload("hello world".getBytes()).build();
        //发送消息
        sendService.sendOrder().send(msg);
        return "SUCCESS";
    }
}

3、消息消费者

一、建立项目

IDEA中建立一个新的SpringBoot项目，名称为“spring-consumer”，SpringBoot版本选择2.1.10，在选择Dependencies(依赖)的界面勾选Web -> Spring Web，Spring Cloud Discovery -> Eureka Discovery Client。
打开pom.xml，添加依赖

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>spring-consumer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-consumer</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-stream-rabbit</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

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

</project>
View Code

二、修改配置application.yml

server:
  port: 8080
spring:
  application:
    name: spring-consumer
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
rabbitmq:
  host: localhost
  post: 5672
  username: guest
  password: guest

三、缩写接受消息的通道接口

package com.example.springconsumer;

import org.springframework.cloud.stream.annotation.Input;
import org.springframework.messaging.SubscribableChannel;

public interface ReceiveService {
    @Input("myInput")
    SubscribableChannel myInput();
}

四、修改启动类代码

一样绑定消息通道

package com.example.springconsumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.stream.annotation.EnableBinding;
import org.springframework.cloud.stream.annotation.StreamListener;

@SpringBootApplication
@EnableBinding(ReceiveService.class)
public class SpringConsumerApplication {

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

    //订阅myInput通道的消息
    @StreamListener("myInput")
    public void receive(byte[] msg){
        System.out.println("接收到的消息：" + new String(msg));
    }
}

五、测试

（1）检查服务里面的RabbitMQ是否有启动（默认启动）；

（2）启动spring-server（8761端口）；

（3）启动spring-producer（8081端口）；

（4）启动spring-consumer（8080端口）；

（5）浏览器访问http://localhost:8081/send，spring-consumer项目的控制台输出：

接收到的消息：hello world

说明消费者已经能够从消息代理中获取到消息。

4、更换绑定器

上面使用了RabbitMQ做为消息代理，若是使用Kafka，能够更换Maven依赖实现。在生产者和消费者的pom.xml中，将spring-cloud-starter-stream-rabbit修改成spring-cloud-starter-stream-kafka。

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