SpringCloud服务发现与负载均衡ribbon（三）

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SpringCloud学习总结

3、服务发现与负载均衡ribbon

一、服务发现

修改provider8001主启动类，增加注解@EnableDiscoveryClient

package com.atguigu.springcloud;

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

@SpringBootApplication
@EnableEurekaClient //本服务启动后会自动注册进eureka服务中
@EnableDiscoveryClient //服务发现
public class DeptProvider8001_App
{
	public static void main(String[] args)
	{
		SpringApplication.run(DeptProvider8001_App.class, args);
	}
}

修改provider8001中的Controller

package com.atguigu.springcloud.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.atguigu.springcloud.entities.Dept;
import com.atguigu.springcloud.service.DeptService;

@RestController
public class DeptController
{
	@Autowired
	private DeptService service;
	@Autowired
	private DiscoveryClient client;

	@RequestMapping(value = "/dept/add", method = RequestMethod.POST)
	public boolean add(@RequestBody Dept dept)
	{
		return service.add(dept);
	}

	@RequestMapping(value = "/dept/get/{id}", method = RequestMethod.GET)
	public Dept get(@PathVariable("id") Long id)
	{
		return service.get(id);
	}

	@RequestMapping(value = "/dept/list", method = RequestMethod.GET)
	public List<Dept> list()
	{
		return service.list();
	}

	
//	@Autowired
//	private DiscoveryClient client;
	@RequestMapping(value = "/dept/discovery", method = RequestMethod.GET)
	public Object discovery()
	{
		List<String> list = client.getServices();
		System.out.println("**********" + list);

		List<ServiceInstance> srvList = client.getInstances("MICROSERVICECLOUD-DEPT");
		for (ServiceInstance element : srvList) {
			System.out.println(element.getServiceId() + "\t" + element.getHost() + "\t" + element.getPort() + "\t"
					+ element.getUri());
		}
		return this.client;
	}

}

修改服务消费consumer80的服务处理类

package com.atguigu.springcloud.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.atguigu.springcloud.entities.Dept;

@RestController
public class DeptController_Consumer
{

	//private static final String REST_URL_PREFIX = "http://localhost:8001";
	private static final String REST_URL_PREFIX = "http://MICROSERVICECLOUD-DEPT";

	/**
	 * 使用 使用restTemplate访问restful接口非常的简单粗暴无脑。 (url, requestMap,
	 * ResponseBean.class)这三个参数分别代表 REST请求地址、请求参数、HTTP响应转换被转换成的对象类型。
	 */
	@Autowired
	private RestTemplate restTemplate;

	@RequestMapping(value = "/consumer/dept/add")
	public boolean add(Dept dept)
	{
		return restTemplate.postForObject(REST_URL_PREFIX + "/dept/add", dept, Boolean.class);
	}

	@RequestMapping(value = "/consumer/dept/get/{id}")
	public Dept get(@PathVariable("id") Long id)
	{
		return restTemplate.getForObject(REST_URL_PREFIX + "/dept/get/" + id, Dept.class);
	}

	@SuppressWarnings("unchecked")
	@RequestMapping(value = "/consumer/dept/list")
	public List<Dept> list()
	{
		return restTemplate.getForObject(REST_URL_PREFIX + "/dept/list", List.class);
	}

	// 测试@EnableDiscoveryClient,消费端可以调用服务发现
	@RequestMapping(value = "/consumer/dept/discovery")
	public Object discovery()
	{
		return restTemplate.getForObject(REST_URL_PREFIX + "/dept/discovery", Object.class);
	}

}

发送请求查看服务发现的情况 http://localhost:80/consumer/dept/discovery

二、负载均衡ribbon

新建服务提供者provider8001模块

拷贝provider8001的pom文件以及yml文件

server:
 port: 8002

mybatis:
 config-location: classpath:mybatis/mybatis.cfg.xml        # mybatis配置文件所在路径
 type-aliases-package: com.atguigu.springcloud.entities    # 所有Entity别名类所在包
 mapper-locations:
 - classpath:mybatis/mapper/**/*.xml                       # mapper映射文件

spring:
  application:
   name: microservicecloud-dept
  datasource:
   type: com.alibaba.druid.pool.DruidDataSource            # 当前数据源操作类型
   driver-class-name: com.mysql.jdbc.Driver              # mysql驱动包
   url: jdbc:mysql://localhost:3306/cloudDB02              # 数据库名称
   username: root
   password: 123321
   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/
 instance:
   instance-id: microservicecloud-dept8002 #自定义服务名称信息
   prefer-ip-address: true     #访问路径可以显示IP地址
#
info:
 app.name: atguigu-microservicecloud
 company.name: www.atguigu.com
 build.artifactId: $project.artifactId$
 build.version: $project.version$

注意：不同的微服务提供者可以连接不同的数据库！！！ 8001连接cloudDB01 8002连接cloudDB02

修改consumer80中的配置类

在注入的RestTemplate 上标注注解@LoadBalanced则可实现负载均衡

package com.atguigu.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.RetryRule;

@Configuration
public class ConfigBean 
{ 
	@Bean
	@LoadBalanced //Spring Cloud Ribbon是基于Netflix Ribbon实现的一套客户端       负载均衡的工具。
	public RestTemplate getRestTemplate()
	{
		return new RestTemplate();
	}
}

启动三个eureka,启动两个provider,启动consumer,查看结果
http://localhost:80/consumer/dept/list

三、选择载均衡算法与自定义算法

在consumer80创建一个配置类

在容器中注入相应的算法类

package com.atguigu.myrule;

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

import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RoundRobinRule;

@Configuration
public class MySelfRule
{
	@Bean
	public IRule myRule()
	{
		//return new RandomRule();// Ribbon默认是轮询，我自定义为随机
		//return new RoundRobinRule();// Ribbon默认是轮询，我自定义为随机
		
		return new RandomRule_ZY();// 我自定义为每台机器5次
	}
}

自定义负载均衡算法

注意：要实现自定义算法，配置类与算法类不能与主启动类在同一个包下！！！，自定义算法类，继承AbstractLoadBalancerRule

//循环调用每个微服务，并且每个调用5次
package com.atguigu.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_ZY 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

	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();
			List<Server> allList = lb.getAllServers();

			int serverCount = allList.size();
			if (serverCount == 0) {
				/*
				 * 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
	}
}

有点模糊，看结构图

仅仅选择不同的负载均衡算法，则直接在ConfigBean里面 注入相应的类
自定义算法，则在myrule包下新建配置类与算法类。
主启动类在springcloud包下

启动三个eureka,启动两个provider,启动consumer,再次查看结果
http://localhost:80/consumer/dept/list

后续：负载均衡feign与Hystrix断路器…