springcloud(二) 负载均衡器 ribbon

代码地址：https://github.com/showkawa/springBoot_2017/tree/master/spb-demo

ribbon是一个负载均衡客户端 类似nginx反向代理，可以很好的控制htt和tcp的一些行为。Feign默认集成了ribbon（默认的负载均衡策略是轮询策略）。

1.启动brian-query-service服务工程，端口号分别为8002、8005，spb-job工程 使用负载均衡策略轮训到会员服务接口。

1.1.1  服务提供者的yml配置应用名称需保持一致

1.1.2 此处仅仅为了测试负载均衡的轮询机制，spb-brian-query-service2服务接口固定返回id=34的数据

1.2  修改spb-job项目，使其成为brian-query-service服务的消费者

1.2.1  yml配置文件添加负载均衡器

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.kawa</groupId>
        <artifactId>spb-demo</artifactId>
        <version>0.0.2</version>
    </parent>

    <groupId>com.kawa</groupId>
    <artifactId>spb-job</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spb-job</name>
    <description>控制中心</description>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
            <version>2.0.2.RELEASE</version>
            <exclusions>
                <exclusion>
                    <artifactId>servlet-api</artifactId>
                    <groupId>javax.servlet</groupId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-rabbin</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</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>Dalston.RC1</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>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
</project>

1.2.1 spb-job 启动类开启ribbon

@LoadBalanced注解表明这个restRemplate开启负载均衡的功能。

package com.kawa.spbjob;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableScheduling
@EnableEurekaClient
public class SpbJobApplication {

    @Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        return new RestTemplate();
    }

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

}

3.启动spb-job测试接口服务