SpringCloud Netflix Ribbon超详细讲解

     <!--引入Eureka的依赖-->
     <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>
        <!--引入ribbon-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>
    </dependencies>

package com.you.controller;
import com.you.pojo.Dept;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;
import java.util.List;
@RestController
@ResponseBody
public class DeptComsumerController {
    @Autowired
    RestTemplate restTemplate;
//    public static final String REST_URL_PREFIX = "http://localhost:8001";
    public static final String REST_URL_PREFIX = "http://SPRINGCLOUD-PROVIDER-DEPT";
    @GetMapping("/consumer/dept/getDept/{id}")
    public Dept getDeptOfId(@PathVariable("id") Long id)
    {
        System.out.println(REST_URL_PREFIX+"/dept"+"/aDept/"+id);
        return restTemplate.getForObject(REST_URL_PREFIX + "/dept" + "/aDept/"+id, Dept.class);
    }
}

package com.you.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 {
    @Bean
    @LoadBalanced  //ribbon
    /*配置负载均衡实现RestTemplate*/
    /*IRule*/
    /*RoundRobinRule 轮询 */
    /*RandomRule 随机*/
    /*AvailabilityFilteringRule 优先过滤掉跳闸、访问故障的服务，对剩下的进行轮询 */
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }
}

package com.you;
import com.tan.tanRule;
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
/*下面是处理负载均衡算法*/
@RibbonClient(name = "SPRINGCLOUD-PROVIDER-DEPT",configuration = tanRule.class)
public class DeptConsumer_80 {
    public static void main(String[] args) {
        SpringApplication.run(DeptConsumer_80.class,args);
    }
}

package com.tan;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;
import org.springframework.context.annotation.Bean;
public class tanRule {
    @Bean
    public IRule myRule()
    {
        return new tanRandomRule();
    }
}

package com.tan;
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 tanRandomRule extends AbstractLoadBalancerRule {
   int total = 0;
   int currentIndex = 0;
   public tanRandomRule() {
   }
   @SuppressWarnings({"RCN_REDUNDANT_NULLCHECK_OF_NULL_VALUE"})
   public Server choose(ILoadBalancer lb, Object key) {
       if (lb == null) {
           return null;
       } else {
           Server server = null;
           while(server == null) {
               if (Thread.interrupted()) {
                   return null;
               }
               List<Server> upList = lb.getReachableServers();
               List<Server> allList = lb.getAllServers();
               if(total<5)
               {
                   server = (Server)upList.get(currentIndex);
                   total++;
               }else{
                   total = 0;
                   currentIndex++;
                   if(currentIndex>2)
                   {
                       currentIndex = 0;
                   }
                   server = (Server)upList.get(currentIndex);
               }
               System.out.println("CurrentIndex:"+currentIndex);
               System.out.println("Total:"+total);
               System.out.println("sever 的值是:"+server);
               if (server == null) {
                   Thread.yield();
               } else {
                   if (server.isAlive()) {
                       return server;
                   }
                   server = null;
                   Thread.yield();
               }
           }
           return server;
       }
   }
   protected int chooseRandomInt(int serverCount) {
       return ThreadLocalRandom.current().nextInt(serverCount);
   }
   public Server choose(Object key) {
       return this.choose(this.getLoadBalancer(), key);
   }
   public void initWithNiwsConfig(IClientConfig clientConfig) {
   }
}