SpringCloud客户端的负载均衡Ribbon的实现

程序员文章站 2023-12-18 21:24:04

前言：微服务架构，不可避免的存在单个微服务有多个实例，那么客户端如何将请求分摊到多个微服务的实例上呢？这里我们就需要使用负载均衡了一、ribbon简介 ribbon是...

前言：微服务架构，不可避免的存在单个微服务有多个实例，那么客户端如何将请求分摊到多个微服务的实例上呢？这里我们就需要使用负载均衡了

一、ribbon简介

ribbon是netflix发布的负载均衡器，它有助于控制http和tcp客户端的行为。为ribbon配置服务提供者地址列表后，ribbon就可基于某种负载均衡算法，自动地帮助服务消费者去请求。ribbon默认为我们提供了很多的负载均衡算法，例如：轮询，随机等，也可自定义；

ribbon的github： https://github.com/netflix/ribbon

而在springcloud中使用ribbon和eureka时，ribbon会自动从eurekaserver中获取服务提供者地址列表，并基于负载均衡算法。

二、ribbon实战

1、创建eurekaserver，eurekaclient1，eurekaclient2，之前已经说过了eureka的使用，这里直接上代码：

eurekaserver：

serverapplication.java

@springbootapplication
@enableeurekaserver
public class serverapplication {

  public static void main(string[] args) {
    springapplication.run(serverapplication.class,args);
  }

}

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>com.cn</groupid>
 <artifactid>eureka-ribbon-server</artifactid>
 <version>1.0-snapshot</version>

 <properties>
  <project.build.sourceencoding>utf-8</project.build.sourceencoding>
  <java.version>1.8</java.version>
 </properties>

 <parent>
  <groupid>org.springframework.boot</groupid>
  <artifactid>spring-boot-starter-parent</artifactid>
  <version>1.5.13.release</version>
 </parent>

 <dependencies>
  <dependency>
   <groupid>org.springframework.</groupid>
   <artifactid></artifactid>
  </dependency>
  <dependency>
   <groupid>org.springframework.cloud</groupid>
   <artifactid>spring-cloud-starter-eureka-server</artifactid>
  </dependency>
 </dependencies>
 <dependencymanagement>
  <dependencies>
   <dependency>
    <groupid>org.springframework.cloud</groupid>
    <artifactid>spring-cloud-dependencies</artifactid>
    <version>edgware.sr3</version>
    <type>pom</type>
    <scope>import</scope>
   </dependency>
  </dependencies>
 </dependencymanagement>
 <!-- 添加spring-boot的maven插件 -->
 <build>
  <plugins>
   <plugin>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-maven-plugin</artifactid>
   </plugin>
  </plugins>
 </build>
</project>

application.properties

server.port=8761
#注意：这两个配置eureka默认为true，要改成false，否则会报错，connot connect server
#表示是否将自己注册在eurekaserver上
eureka.client.register-with-eureka=false
#表示是否从eurekaserver获取注册信息
eureka.client.fetch-registry=false

eureka.client.service-url.defaultzone=http://localhost:8761/eureka/

eurekaclient1:

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>com.cn</groupid>
 <artifactid>eureka-ribbon-client</artifactid>
 <version>1.0-snapshot</version>

 <properties>
  <project.build.sourceencoding>utf-8</project.build.sourceencoding>
  <java.version>1.8</java.version>
 </properties>

 <parent>
  <groupid>org.springframework.boot</groupid>
  <artifactid>spring-boot-starter-parent</artifactid>
  <version>1.5.13.release</version>
 </parent>

 <dependencies>
  <dependency>
   <groupid>org.springframework.cloud</groupid>
   <artifactid>spring-cloud-starter-ribbon</artifactid>
  </dependency>
  <dependency>
   <groupid>org.springframework.cloud</groupid>
   <artifactid>spring-cloud-starter-eureka</artifactid>
  </dependency>
 </dependencies>
 <dependencymanagement>
  <dependencies>
   <dependency>
    <groupid>org.springframework.cloud</groupid>
    <artifactid>spring-cloud-dependencies</artifactid>
    <version>edgware.sr3</version>
    <type>pom</type>
    <scope>import</scope>
   </dependency>
  </dependencies>
 </dependencymanagement>
 <!-- 添加spring-boot的maven插件 -->
 <build>
  <plugins>
   <plugin>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-maven-plugin</artifactid>
   </plugin>
  </plugins>
 </build>
</project>

server.port=8762
spring.application.name=client-8762
eureka.client.service-url.defaultzone=http://localhost:8761/eureka/

而在启动类中加入resttemplate远程调用实例到容器中，并且添加loadbalanced注解，使resttemplate具备负载均衡的能力：

@springbootapplication
@enablediscoveryclient
public class clientapplication {

  public static void main(string[] args) {
    springapplication.run(clientapplication.class, args);
  }

  /** 
   * @description: 加入@loadbalanced注解，就可以为resttemplate加入负载均衡的能力 
   * @param:
   * @return: 
   * @author: 
   * @date: 2018/6/15 
   */ 
  @bean
  @loadbalanced
  public resttemplate getresttemplate() {
    return new resttemplate();
  }

}

创建controller，注入resttemplate、loadbalancerclient实例：

package com.cn.controller;

import org.springframework.beans.factory.annotation.autowired;
import org.springframework.cloud.client.serviceinstance;
import org.springframework.cloud.client.loadbalancer.loadbalancerclient;
import org.springframework.stereotype.controller;
import org.springframework.web.bind.annotation.getmapping;
import org.springframework.web.bind.annotation.responsebody;
import org.springframework.web.client.resttemplate;

/**
 * @program: springcloud-example
 * @description:
 * @author: 
 * @create: 2018-06-15 15:55
 **/
@controller
public class ribboncontroller {

  @autowired
  private loadbalancerclient loadbalancerclient;

  @autowired
  private resttemplate resttemplate;

  @getmapping("/loadinstance")
  @responsebody
  public string loadinstance() {
    serviceinstance choose = this.loadbalancerclient.choose("client-87");
    system.out.println(choose.getserviceid()+":"+choose.gethost()+":"+choose.getport());
    return choose.getserviceid() + ":" + choose.gethost() + ":" + choose.getport();
  }

}

package com.cn;

import org.springframework.boot.springapplication;
import org.springframework.boot.autoconfigure.springbootapplication;
import org.springframework.cloud.client.discovery.enablediscoveryclient;

/**
 * @program: springcloud-example
 * @description:
 * @author: 535504
 * @create: 2018-06-15 16:05
 **/
@springbootapplication
@enablediscoveryclient
public class clientapplication {

  public static void main(string[] args) {
    springapplication.run(clientapplication.class, args);
  }

}

eurekaclient2：

pom.xml与eurekaclient1中一致

application.xml:

server.port=8763
spring.application.name=client-87
eureka.client.service-url.defaultzone=http://localhost:8761/eureka

clientcontroller.java:

package com.cn.contorller;

import org.springframework.stereotype.controller;
import org.springframework.web.bind.annotation.getmapping;
import org.springframework.web.bind.annotation.responsebody;

/**
 * @program: springcloud-example
 * @description:
 * @author: 
 * @create: 2018-06-15 16:12
 **/
@controller
public class clientcontroller {

  @getmapping("/getuser")
  @responsebody
  public string getuser() {
    system.out.println("获取用户成功");
    return "获取用户成功";
  }

}

2、启动顺序：

①、依次启动eurekaserver =》 eurekaclient1 =》 eurekaclient2 ；

②、然后将eurekaclient2中的application.properties的server.port=8763改为server.port=8764，再次启动该项目;

③、打开eurekaserver的配置页面（http://localhost:8761/），如下：

SpringCloud客户端的负载均衡Ribbon的实现