ribbon是什么?
- Spring Cloud Ribbon是一个基于HTTP和TCP的客户端负载均衡工具,它基于Netflix Ribbon实现
- Ribbon客户端组件提供一系列完善的配置项如连接超时,重试等。简单的说,Ribbon是一个客户端负载均衡器,我们可以在配置文件中Load Balancer后面的所有机器,Ribbon会自动的帮助你基于某种规则(如简单轮询,随机连接等)去连接这些机器,我们也很容易使用Ribbon实现自定义的负载均衡算法
- 常见的负载均衡软件有Nginx、Lvs 等等。
- 负载均衡简单说就是将用户的请求平摊的分配到多个服务器上,从而达到系统的HA(高可用)
入门案例
- 客户端引入依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
- 客户端yml配置文件
server:
port: 80
eureka:
client:
register-with-eureka: false
service-url:
defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/
- 客户端config配置类
package com.kuang.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;
@Configuration
public class ConfigBean { //@Configuration -- spring applicationContext.xml
//配置负载均衡实现RestTemplate
// IRule
// RoundRobinRule 轮询
// RandomRule 随机
// AvailabilityFilteringRule : 会先过滤掉,跳闸,访问故障的服务~,对剩下的进行轮询~
// RetryRule : 会先按照轮询获取服务~,如果服务获取失败,则会在指定的时间内进行,重试
@Bean
@LoadBalanced //Ribbon
public RestTemplate getRestTemplate(){
return new RestTemplate();
}
}
- 客户端Controller层
package com.kuang.springcloud.controller;
import com.kuang.springcloud.pojo.Dept;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
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 java.util.List;
@RestController
public class DeptConsumerController {
@Autowired
private RestTemplate restTemplate;
private static final String REST_URL_PREFIX = "http://SPRINGCLOUD-PROVIDER-DEPT";
@RequestMapping("/consumer/dept/add")
public boolean add(Dept dept){
return restTemplate.postForObject(REST_URL_PREFIX+"/dept/add",dept,Boolean.class);
}
@RequestMapping("/consumer/dept/get/{id}")
public Dept get(@PathVariable("id") Long id){
return restTemplate.getForObject(REST_URL_PREFIX+"/dept/get/"+id,Dept.class);
}
@RequestMapping("/consumer/dept/list")
public List<Dept> list(){
return restTemplate.getForObject(REST_URL_PREFIX+"/dept/list",List.class);
}
}
- 客户端入口
package com.kuang.springcloud;
import com.kuang.myrule.KuangRule;
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;
@SpringBootApplication
@EnableEurekaClient
public class DeptConsumer_80 {
public static void main(String[] args) {
SpringApplication.run(DeptConsumer_80.class,args);
}
}
自定义均衡负载算法
- 编写myrule组件,注意不可以放在主应用程序的上下文,会被componentscan扫描到。
package com.kuang.myrule;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RoundRobinRule;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class KuangRule {
@Bean
public IRule myRule(){
return new KuangRandomRule();
}
}
package com.kuang.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 KuangRandomRule extends AbstractLoadBalancerRule {
private int total = 0;
private int currentIndex = 0;
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) {
return null;
}
if (total<5){
server = upList.get(currentIndex);
total++;
}else {
total = 0;
currentIndex++;
if (currentIndex>upList.size()){
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) {
}
}
- 自定义主文件入口
package com.kuang.springcloud;
import com.kuang.myrule.KuangRule;
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;
@SpringBootApplication
@EnableEurekaClient
@RibbonClient(name = "SPRINGCLOUD-PROVIDER-DEPT",configuration = KuangRule.class)
public class DeptConsumer_80 {
public static void main(String[] args) {
SpringApplication.run(DeptConsumer_80.class,args);
}
}
- 文件目录:(myrule、springcloud、与主程序同级)
[1]: 代码来源:狂神说Java