負載均衡---ribbon

時間 2019-11-29

原文原文鏈接

Ribbon:提供雲端負載均衡，有多種負載均衡策略可供選擇，可配合服務發現和斷路器使用。java

上一篇簡單講解了eureka的使用，這一篇文章基於上一篇的基礎上，講一下springcloud的另外一個重要的組件ribbon。git

這篇文章須要新建三個工程，service（8762），service（8763），service-ribbon（8764），三個服務分別向eureka-server註冊中心註冊，本文的服務使用的註冊中心都是本人建立的測試eureka--eureka.dalaoyang.cn。web

首先新建一個service（8762），括號內的8762是項目的端口號，加入eureka依賴，pom文件以下：spring

<?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>com.dalaoyang</groupId>
    <artifactId>springcloud_service</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springcloud_service</name>
    <description>springcloud_service</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Edgware.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</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>
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配置文件apache

##端口號
server.port=8762

##服務名稱
spring.application.name=service

##註冊中心地址
eureka.client.service-url.defaultZone=http://eureka.dalaoyang.cn/eureka/
複製代碼

啓動類使用註解@EnableEurekaClient向註冊中心註冊，代碼以下：springboot

package com.dalaoyang;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
@EnableEurekaClient
public class SpringcloudServiceApplication {

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


    @Value("${server.port}")
    String port;

    @Value("${spring.application.name}")
    String serviceName;

    @GetMapping("/")
    public String index(){
        return "serviceName=" + serviceName + "-------port=" + port;
    }
}
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到這裏service（8762）建立完成，而後複製一個項目，端口號改成8763做爲service（8763）。bash

而後新建項目service-ribbon（8764），pom文件加入ribbon依賴，pom完整代碼以下：app

<?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>com.dalaoyang</groupId>
    <artifactId>springcloud_ribbon</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springcloud_ribbon</name>
    <description>springcloud_ribbon</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Edgware.SR1</spring-cloud.version>
    </properties>

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

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

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

            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
        </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>

複製代碼

配置文件以下：負載均衡

##端口號
server.port=8764

##服務名稱
spring.application.name=service_ribbon

##註冊中心地址
eureka.client.service-url.defaultZone=http://eureka.dalaoyang.cn/eureka/
複製代碼

因爲只是一個簡單demo，全部我將java代碼都寫在了啓動類裏面，解釋一下，@LoadBalanced放在RestTemplate上面，代表RestTemplate開啓負載均衡。代碼以下：maven

package com.dalaoyang;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
@RestController
public class SpringcloudRibbonApplication {

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

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

	@Value("${server.port}")
	String port;

	@Value("${spring.application.name}")
	String serviceName;

	@GetMapping("/")
	public String index(){
		return restTemplate().getForObject("http://service/",String.class);
	}
}
複製代碼