【SpringCloud】SpringCloud基础教程(4)

前言：

本文内容：Ribbon：负载均衡及Ribbon、使用Ribbon实现负载均衡、自定义负载均衡策略

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Ribbon：负载均衡及Ribbon

Ribbon是什么

Spring Cloud Ribbon是基于Netflix Ribbon实现的一套客户端负载均衡工具
Ribbon主要提供客户端软件负载均衡算法，将Netflix的中间层服务连接在一起。Ribbon的客户端组件提供一系列完整的配置

Ribbon能干什么

LB，即负载均衡(Load Balance)，在微服务或分布式集群中经常使用
负载均衡简单说就是将用户的请求平均分摊到多个服务上，从而达到系统的HA(高可用)
常见的负载均衡有Nginx、Lvs等
Dubbo和SpringCloud均为我们提供了负载均衡，SpringCloud的负载均衡算法可以自定义
负载均衡简单分类：
- 集中式LB
  - 即在服务的消费方和提供方之间使用独立的LB设施，如Nginx，由该设施负责把访问请求通过某种策略转发至服务提供方
- 进程式LB
  - 将LB逻辑集成到消费方，消费方从服务注册中心获知有哪些地址可用，然后再从这些地址中选出一个合适的服务器
  - Ribbon属于进程内LB，它只是一个类库，集成于消费方进程，消费方通过它来获取服务提供方地址

环境搭建

打开springcloud-consumer-dept-80的pom文件，引入依赖

<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-netflix-ribbon</artifactId>
</dependency>

打开application，添加配置

# Eureka
eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002,http://eureka7003.com:7003

打开主启动类，添加注解

package com.jokerdig.springcloud;

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

/**
 * @author Joker大雄
 * @data 2022/8/3 - 15:28
 **/
@SpringBootApplication
@EnableEurekaClient
public class DeptConsumer_80 {
    public static void main(String[] args) {
        SpringApplication.run(DeptConsumer_80.class,args);
    }
}

在config包下的ConfigBean中配置负载均衡

package com.jokerdig.springcloud.config;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

/**
 * @author Joker大雄
 * @data 2022/8/3 - 15:14
 **/
@Configuration
public class ConfigBean {

    @Bean
    @LoadBalanced // Ribbon负载均衡
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }
}

修改controller包下的DeptConsumerController类中的内容

1
2
3

// private static final String REST_URL_PREFIX="http://localhost:8001";
// Ribbon实现
private static final String REST_URL_PREFIX="http://SPRINGCLOUD-PROVIDER-DEPT";

启动端口为7001，7002，7003，8001，80的模块，运行测试

http://localhost/consumer/dept/list

[{"deptno":1,"dname":"开发部","db_source":"db01"},{"deptno":2,"dname":"生产部","db_source":"db01"},{"deptno":3,"dname":"研发部","db_source":"db01"},{"deptno":4,"dname":"人事部","db_source":"db01"},{"deptno":5,"dname":"运维部","db_source":"db01"}]

小结

Ribbon和Eureka整合后，客户端可以直接调用，不用关心IP地址和端口号

Ribbon：使用Ribbon实现负载均衡

创建多个服务提供者进行负载均衡

新建db02和db03数据库

db02

create database db02;

use db02;

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for dept
-- ----------------------------
DROP TABLE IF EXISTS `dept`;
CREATE TABLE `dept`  (
  `deptno` bigint(0) NOT NULL AUTO_INCREMENT,
  `dname` varchar(60) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `db_source` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  PRIMARY KEY (`deptno`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci COMMENT = '部门表' ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of dept
-- ----------------------------
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('开发部', DATABASE());
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('生产部', DATABASE());
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('研发部', DATABASE());
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('人事部', DATABASE());
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('运维部', DATABASE());

SET FOREIGN_KEY_CHECKS = 1;

db03

create database db03;

use db03;

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for dept
-- ----------------------------
DROP TABLE IF EXISTS `dept`;
CREATE TABLE `dept`  (
  `deptno` bigint(0) NOT NULL AUTO_INCREMENT,
  `dname` varchar(60) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `db_source` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  PRIMARY KEY (`deptno`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci COMMENT = '部门表' ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of dept
-- ----------------------------
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('开发部', DATABASE());
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('生产部', DATABASE());
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('研发部', DATABASE());
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('人事部', DATABASE());
INSERT INTO `dept`(`dname`,`db_source`) VALUES ('运维部', DATABASE());

SET FOREIGN_KEY_CHECKS = 1;

创建springcloud-provider-dept-8002(数据库db02)和springcloud-provider-dept-8003数据库db03)的Module，内容与springcloud-provider-dept-8002基本一致，除了数据库的变化

博主8G内存同时运行4个项目已经占用已经满了，这部分推荐16G以上内存的电脑运行 orz
按顺序启动7001，7002，7003(可选)，8001，8002，8003(可选)，80等端口的项目/(ㄒoㄒ)/~~

运行测试

http://localhost/consumer/dept/list

每一次刷新访问，都会按照负载均衡的算法去访问最优的服务提供者

// 每一次刷新访问
[{"deptno":1,"dname":"开发部","db_source":"db01"},{"deptno":2,"dname":"生产部","db_source":"db01"},{"deptno":3,"dname":"研发部","db_source":"db01"},{"deptno":4,"dname":"人事部","db_source":"db01"},{"deptno":5,"dname":"运维部","db_source":"db01"}]

// 每一次刷新访问
[{"deptno":1,"dname":"开发部","db_source":"db03"},{"deptno":2,"dname":"生产部","db_source":"db03"},{"deptno":3,"dname":"研发部","db_source":"db03"},{"deptno":4,"dname":"人事部","db_source":"db03"},{"deptno":5,"dname":"运维部","db_source":"db03"}]

// 每一次刷新访问
[{"deptno":1,"dname":"开发部","db_source":"db02"},{"deptno":2,"dname":"生产部","db_source":"db02"},{"deptno":3,"dname":"研发部","db_source":"db02"},{"deptno":4,"dname":"人事部","db_source":"db02"},{"deptno":5,"dname":"运维部","db_source":"db02"}]

Ribbon：自定义负载均衡策略

打开springcloud-consumer-dept-80项目config包下的ConfigBean，配置官方的IRule

package com.jokerdig.springcloud.config;

import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

/**
 * @author Joker大雄
 * @data 2022/8/3 - 15:14
 **/
@Configuration
public class ConfigBean {

    // 配置负载均衡实现RestTemplate
    // IRule
    // RoundRobinRule 轮询
    // RandomRule 随机
    // AvailabilityFilterIngRule：过滤掉故障服务
    // RetryRule 先按照轮询获取服务，如果获取失败，在指定时间内重试
    @Bean
    @LoadBalanced // 负载均衡
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }

    // 随机 这是官方写好的
    // 自定义Rule的时候这个方法要注释掉
    @Bean
    public IRule myIRule(){
        return new RandomRule();
    }
}

启动所有的Module进行测试

http://localhost/consumer/dept/list

每一次刷新，都会随机访问服务提供者

1
2
3

// 每一次刷新访问
[{"deptno":1,"dname":"开发部","db_source":"db01"},{"deptno":2,"dname":"生产部","db_source":"db01"},{"deptno":3,"dname":"研发部","db_source":"db01"},{"deptno":4,"dname":"人事部","db_source":"db01"},{"deptno":5,"dname":"运维部","db_source":"db01"}]
// .......省略

自定义IRule，新建包com.jokerdig.myrule，在包下新建JokerdigRule和JokerdigRandomRule

这里包没有建在springcloud下而是它上一级的jokerdig下是为了防止被主启动类扫描到，导致自定义与原生的发生冲突

JokerdigRule

package com.jokerdig.myrule;

import com.netflix.loadbalancer.IRule;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @author Joker大雄
 * @data 2022/8/5 - 13:03
 **/
@Configuration
public class JokerdigRule {


    // 自定义
    @Bean
    public IRule myIRule(){
        return new JokerdigRandomRule();
    }
}

JokerdigRandomRule

package com.jokerdig.myrule;

import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.Server;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

public class JokerdigRandomRule extends AbstractLoadBalancerRule {

    // 自定义 这里所写内容仅供测试和了解自定义 并非实际使用
    private int total = 0; // 被调用次数
    private int currentIndex = 0; // 当前提供服务者


    public Server choose(ILoadBalancer lb, Object key) {
        if (lb == null) {
            return null;
        }
        Server server = null;

        while (server == null) {
            if (Thread.interrupted()) {
                return null;
            }
            List<Server> upList = lb.getReachableServers();// 获取存活的服务
            List<Server> allList = lb.getAllServers();// 获取全部服务

            int serverCount = allList.size();
            if (serverCount == 0) {
                return null;
            }

            // nt index = chooseRandomInt(serverCount); // 生成区间随机数
            // server = upList.get(index); // 从存活的服务中随机获取一个
            // 自定义
            if(total<5){
                server = upList.get(currentIndex);
                total++;
            }else{
                total = 0;
                currentIndex++;
                if(currentIndex>upList.size()-1){
                    currentIndex = 0;
                }
                server = upList.get(currentIndex);
            }


            if (server == null) {
                Thread.yield();
                continue;
            }

            if (server.isAlive()) {
                return (server);
            }

           server = null;
            Thread.yield();
        }

        return server;

    }

    protected int chooseRandomInt(int serverCount) {
        return ThreadLocalRandom.current().nextInt(serverCount);
    }

    @Override
    public Server choose(Object key) {
        return choose(getLoadBalancer(), key);
    }

    @Override
    public void initWithNiwsConfig(IClientConfig clientConfig) {
        // TODO Auto-generated method stub

    }
}

修改主启动类，添加@RibbonClient的注解

package com.jokerdig.springcloud;

import com.jokerdig.myrule.JokerdigRule;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;

/**
 * @author Joker大雄
 * @data 2022/8/3 - 15:28
 **/
@SpringBootApplication
@EnableEurekaClient
// 在微服务启动就能加载自定义的Ribbon类
@RibbonClient(name = "SPRINGCLOUD-PROVIDER-DEPT",configuration = JokerdigRule.class)
public class DeptConsumer_80 {
    public static void main(String[] args) {
        SpringApplication.run(DeptConsumer_80.class,args);
    }
}

启动所有模块，进行测试

http://localhost/consumer/dept/list

每刷新到第5次，会更换所访问服务提供者