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 lzh
 * create 2019-11-05-9:58
 */
@Configuration
public class ConfigBean {

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

}

import com.lzh.cloud.model.Dept;
import com.lzh.cloud.service.DeptService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

import java.util.List;

/**
 * @author lzh
 * create 2019-11-05-10:27
 */
@Service
public class DeptServiceImpl implements DeptService {


    /**
     * 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;

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

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

    @Override
    public Dept get(Long id) {
        return restTemplate.getForObject(REST_URL_PREFIX + "/dept/get/" + id, Dept.class);
    }

    @Override
    public List<Dept> list() {
        return restTemplate.getForObject(REST_URL_PREFIX + "/dept/list/", List.class);
    }

    @Override
    public Object discovery() {
        return restTemplate.getForObject(REST_URL_PREFIX + "/dept/discovery", Object.class);
    }
}

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

/**
 * @author lzh
 * create 2019-05-19-17:10
 */

@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_LZH(); // 我自定义为每台机器5次
    }

}

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;

public class RandomRule_LZH 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

    }

}

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;


/**
 * @author lzh
 * create 2019-11-04-22:26
 */
@SpringBootApplication
@EnableEurekaClient
//自定义负载均衡规则
//在启动该为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
//configuration = MySelfRule.class  把MySelfRule配置类加载进容器
@RibbonClient(name = "MICROSERVICECLOUD-DEPT",configuration = MySelfRule.class)
@EnableDiscoveryClient
public class MyConsumerApplication_80 {
    public static void main(String[] args) {
        SpringApplication.run(MyConsumerApplication_80.class);
    }
}