搭建springcloud的demo之Ribbon负载均衡(五)

Ribbon的负载均衡算法

默认简单轮询算法:一台服务器一次

Ribbon在工作时分成两步
第一步先选择EurekaServer,它优先选择在同一个区域内负载较少的server;
第二步再根据用户指定的策略,在从server取到的服务注册列表中选择一个地址;

参考microservicecloud-provider-dept-8001,新建两份,分别命名为8002,8003

<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.yt.springcloud</groupId>
    <artifactId>microservicecloud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <artifactId>microservicecloud-provider-dept-8002</artifactId>
  
  <dependencies>
  
  <!-- 引入自己已定义的api通用包,可以使用Dept部门Entity -->
  	<dependency>
  		<groupId>com.yt.springcloud</groupId> 
  		<artifactId>microservicecloud-api</artifactId>
  		<version>${project.version}</version>
  	</dependency>
  	
  	 <!-- junit的jar包 -->
  	<dependency>
  		<groupId>junit</groupId>
  		<artifactId>junit</artifactId>
  	</dependency>
  	
  	 <!-- mysql的jar包 -->
  	<dependency>
  		<groupId>mysql</groupId>
  		<artifactId>mysql-connector-java</artifactId>
  	</dependency>
  	
  	 <!-- druid的jar包 -->
  	<dependency>
  		<groupId>com.alibaba</groupId>
  		<artifactId>druid</artifactId>
  	</dependency>
  	
  	 <!-- mybatis的整合 -->
  	<dependency>
  		<groupId>org.mybatis.spring.boot</groupId>
  		<artifactId>mybatis-spring-boot-starter</artifactId>
  	</dependency>
  	
  	 <!-- springboot的整合jetty 微服务架构不发布在tomcat下面,内嵌的父容器 -->
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-jetty</artifactId>
  	</dependency>
  	
  	 <!-- springboot的整合web-->
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-web</artifactId>
  	</dependency>
  	
  	 <!-- springboot的整合测试 -->
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-test</artifactId>
  	</dependency>
  	
  	
  	 <!-- 修改后立即生效,热部署 (一修改,自动发布,自动构建)-->
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>springloaded</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-devtools</artifactId>
  	</dependency>
  	
  	 <!-- 将微服务provider侧注册进入eureka(引入eureka的client端) -->
  	<dependency>
  		<groupId>org.springframework.cloud</groupId>
  		<artifactId>spring-cloud-starter-eureka</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.cloud</groupId>
  		<artifactId>spring-cloud-starter-config</artifactId>
  	</dependency>
  	
  	 <!-- actuator监控信息完善 -->
  	<dependency>
  		<groupId>org.springframework.boot</groupId> 
  		<artifactId>spring-boot-starter-actuator</artifactId>
  	</dependency>
  	
  </dependencies>
  
</project>

<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.yt.springcloud</groupId>
    <artifactId>microservicecloud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <artifactId>microservicecloud-provider-dept-8003</artifactId>
  
  <dependencies>
  
  <!-- 引入自己已定义的api通用包,可以使用Dept部门Entity -->
  	<dependency>
  		<groupId>com.yt.springcloud</groupId> 
  		<artifactId>microservicecloud-api</artifactId>
  		<version>${project.version}</version>
  	</dependency>
  	
  	 <!-- junit的jar包 -->
  	<dependency>
  		<groupId>junit</groupId>
  		<artifactId>junit</artifactId>
  	</dependency>
  	
  	 <!-- mysql的jar包 -->
  	<dependency>
  		<groupId>mysql</groupId>
  		<artifactId>mysql-connector-java</artifactId>
  	</dependency>
  	
  	 <!-- druid的jar包 -->
  	<dependency>
  		<groupId>com.alibaba</groupId>
  		<artifactId>druid</artifactId>
  	</dependency>
  	
  	 <!-- mybatis的整合 -->
  	<dependency>
  		<groupId>org.mybatis.spring.boot</groupId>
  		<artifactId>mybatis-spring-boot-starter</artifactId>
  	</dependency>
  	
  	 <!-- springboot的整合jetty 微服务架构不发布在tomcat下面,内嵌的父容器 -->
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-jetty</artifactId>
  	</dependency>
  	
  	 <!-- springboot的整合web-->
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-web</artifactId>
  	</dependency>
  	
  	 <!-- springboot的整合测试 -->
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-starter-test</artifactId>
  	</dependency>
  	
  	
  	 <!-- 修改后立即生效,热部署 (一修改,自动发布,自动构建)-->
  	<dependency>
  		<groupId>org.springframework</groupId>
  		<artifactId>springloaded</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.boot</groupId>
  		<artifactId>spring-boot-devtools</artifactId>
  	</dependency>
  	
  	 <!-- 将微服务provider侧注册进入eureka(引入eureka的client端) -->
  	<dependency>
  		<groupId>org.springframework.cloud</groupId>
  		<artifactId>spring-cloud-starter-eureka</artifactId>
  	</dependency>
  	<dependency>
  		<groupId>org.springframework.cloud</groupId>
  		<artifactId>spring-cloud-starter-config</artifactId>
  	</dependency>
  	
  	 <!-- actuator监控信息完善 -->
  	<dependency>
  		<groupId>org.springframework.boot</groupId> 
  		<artifactId>spring-boot-starter-actuator</artifactId>
  	</dependency>
  	
  </dependencies>
  
</project>

新建8002/8003数据库,各自微服务分别连接各自的数据库

DROP DATABASE IF EXISTS cloudDB02;
CREATE DATABASE cloudDB02 CHARACTER SET UTF8;
USE cloudDB02;
CREATE TABLE dept(
	deptno BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
	dname VARCHAR(60),
	db_source VARCHAR(60)
);

INSERT INTO dept(dname,db_source)VALUES ('开发部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('人事部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('财务部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('市场部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('运维部',DATABASE());

SELECT * FROM dept;

DROP DATABASE IF EXISTS cloudDB03;
CREATE DATABASE cloudDB03 CHARACTER SET UTF8;
USE cloudDB03;
CREATE TABLE dept(
	deptno BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
	dname VARCHAR(60),
	db_source VARCHAR(60)
);

INSERT INTO dept(dname,db_source)VALUES ('开发部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('人事部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('财务部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('市场部',DATABASE());
INSERT INTO dept(dname,db_source)VALUES ('运维部',DATABASE());

SELECT * FROM dept;

修改8002的yml

server:
  port: 8002                                         # 当前微服务的端口
  
mybatis:
  config-location: classpath:mybatis/mybatis.cfg.xml # mybatis配置文件所在路径
  type-aliases-package: com.yt.springcloud.entity    # 所有饿entity实体类所在包
  mapper-locations:
  - classpath:mybatis/mapper/**/*.xml                # mapper映射文件

spring:
  application:
   name: microservicecloud-dept                      # 对外暴露的微服务的名字(很重要)
  datasource:
   type: com.alibaba.druid.pool.DruidDataSource      # 当前数据源操作类型
   driver-class-name: org.gjt.mm.mysql.Driver        # mysql驱动包
   url: jdbc:mysql://localhost:3306/cloudDB02        # 数据库名称
   username: root
   password: hannong
   dbcp2:
    min-idle: 5                                      # 数据库连接池的最小维持连接数 
    initial-size: 5                                  # 初始化连接数
    max-total: 5                                     # 最大连接数
    max-wait-millis: 200                             # 等待连接获取的最大超时时间
    
eureka:
   client:   #客户端注册进eureka服务列表内
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/      #去注册中心的地址
      #defaultZone:7001,7002,7003 去注册中心的地址
   instance: 
      instance-id: microservicecloud-dept8002        #修改eureka的服务路径名称
      prefer-ip-address: true                        #访问路径可以显示ip地址

info:
   app.name: yt-microservicecloud                    #
   company.name: www.yt.com                          #
   build.artifactId: $project.artifactId$            #
   build.version: $project.version$                  #


       

修改8003的yml

server:
  port: 8003                                         # 当前微服务的端口
  
mybatis:
  config-location: classpath:mybatis/mybatis.cfg.xml # mybatis配置文件所在路径
  type-aliases-package: com.yt.springcloud.entity    # 所有饿entity实体类所在包
  mapper-locations:
  - classpath:mybatis/mapper/**/*.xml                # mapper映射文件

spring:
  application:
   name: microservicecloud-dept                      # 对外暴露的微服务的名字(很重要)
  datasource:
   type: com.alibaba.druid.pool.DruidDataSource      # 当前数据源操作类型
   driver-class-name: org.gjt.mm.mysql.Driver        # mysql驱动包
   url: jdbc:mysql://localhost:3306/cloudDB03        # 数据库名称
   username: root
   password: hannong
   dbcp2:
    min-idle: 5                                      # 数据库连接池的最小维持连接数 
    initial-size: 5                                  # 初始化连接数
    max-total: 5                                     # 最大连接数
    max-wait-millis: 200                             # 等待连接获取的最大超时时间
    
eureka:
   client:   #客户端注册进eureka服务列表内
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/      #去注册中心的地址
      #defaultZone:7001,7002,7003 去注册中心的地址
   instance: 
      instance-id: microservicecloud-dept8003        #修改eureka的服务路径名称
      prefer-ip-address: true                        #访问路径可以显示ip地址

info:
   app.name: yt-microservicecloud                    #
   company.name: www.yt.com                          #
   build.artifactId: $project.artifactId$            #
   build.version: $project.version$                  #


       

启动3个eureka集群配置区
启动3个Dept微服务并各自测试通过



启动microservicecloud-consumer-dept-80:http://localhost:8003/dept/list

客户端通过Ribbon完成负载均衡并访问上一步的Dept微服务

总结:Ribbon其实就是一个软负载均衡的客户端组件,它可以和其他所需请求的客户端结合使用,和eureka结合只是其中的一个实例;

Ribbon核心组件IRule:根据特定算法中从服务列表中选取一个要访问的服务;

默认的简单轮询算法,改成随机算法

package com.yt.springcloud.cfgbeans;

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;

import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;

@Configuration//其实就是ApplicationContext.xml
public class ConfigBean {
	
	/**
	 * RestTemplate提供了多种便捷访问远程Http服务的方法
	 * 是一种简单便捷的访问restful服务模板类,是Spring提供的用于访问Rest服务的客户端模板工具集
	 * @return
	 */
	@Bean
	@LoadBalanced//ribbon是客户端的负载均衡工具,所以在rest去访问微服务的时候,自带负载均衡,这个注解是开启负载均衡的
	public RestTemplate getRestTemplate() {
		return new RestTemplate();
	}
	
	/**
	 * 有显示的声明算法,就覆盖默认的轮询算法
	 * @return
	 */
	@Bean
	public IRule myRule() {
		
		//return new RoundRobinRule();//轮询算法
		return new RandomRule();//随机算法
	}

}

Ribbon自定义算法

修改microservicecloud-consumer-dept-80
主启动类添加@RibbonClient

package com.yt.springcloud;

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;

import com.yt.myrule.MySelfRule;

@SpringBootApplication
@EnableEurekaClient
//在启动该微服务的时候就能去加载我们的自定义Ribbon配置类，从而使配置生效
@RibbonClient(name="MICROSERVICECLOUD-DEPT",configuration=MySelfRule.class)
public class DeptConsumer80_App {
	
	public static void main(String[] args) {
		SpringApplication.run(DeptConsumer80_App.class, args);
	}

}

注意配置细节

package com.yt.myrule;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;

//自定义负载均衡算法类
@Configuration
public class MySelfRule {
	
	@Bean
	public IRule myRule() {
		return new RandomRule();//Ribbon默认是轮询,我自定义为随机
	}

}

启动3个eureka集群和8001,8002,8003,80等

自定义规则深度解析
创建RandomRule_YT

package com.yt.myrule;

import java.util.List;

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

public class RandomRule_YT extends AbstractLoadBalancerRule{

	// total = 0 // 当total==5以后，我们指针才能往下走，
	// index = 0 // 当前对外提供服务的服务器地址，
	// total需要重新置为零，但是已经达到过一个5次，我们的index = 1
	// 分析：我们5次，但是微服务只有8001 8002 8003 三台，OK？
	// 
	
	private int total = 0; 			// 总共被调用的次数，目前要求每台被调用5次
	private int currentIndex = 0;	// 当前提供服务的机器号

	/**
	 * 返回具体服务的服务器(是8001还是8002还是8003) 
	 * @param lb
	 * @param key
	 * @return
	 */
	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();//活着的,可以对外提供服务的服务器
			List<Server> allList = lb.getAllServers();

			int serverCount = allList.size();//得到服务器的台数
			if (serverCount == 0) {//为0就不进去
				/*
				 * No servers. End regardless of pass, because subsequent passes only get more
				 * restrictive.
				 */
				return null;
			}

//			int index = rand.nextInt(serverCount);// java.util.Random().nextInt(3);
//			server = upList.get(index);

			
//			private int total = 0; 			// 总共被调用的次数，目前要求每台被调用5次
//			private int currentIndex = 0;	// 当前提供服务的机器号
            if(total < 5)
            {
	            server = upList.get(currentIndex);
	            total++;
            }else {
	            total = 0;
	            currentIndex++;
	            if(currentIndex >= upList.size())
	            {
	              currentIndex = 0;
	            }
            }			
			
			
			if (server == null) {
				/*
				 * The only time this should happen is if the server list were somehow trimmed.
				 * This is a transient condition. Retry after yielding.
				 */
				Thread.yield();
				continue;
			}

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

			// Shouldn't actually happen.. but must be transient or a bug.
			server = null;
			Thread.yield();
		}

		return server;

	}

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

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

	}

}

修改MySelfRule类的返回类

package com.yt.myrule;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.netflix.loadbalancer.IRule;

//自定义负载均衡算法类
@Configuration
public class MySelfRule {
	
	@Bean
	public IRule myRule() {
		return new RandomRule_YT();//Ribbon默认是轮询,我自定义为随机
	}

}

启动3个eureka集群,8001,8002,8003,80等