负载均衡框架 ribbon 二

Ribbon 负载均衡机制

官方文档地址：https://github.com/Netflix/ribbon/wiki/Working-with-load-balancers

1. Ribbon 内置的负载均衡规则

　　① RoundRobinRule

　　　　此规则是默认规则，通过轮询服务器列表的方式选择服务器

　　② AvailabilityFilteringRule

　　　　此规则会跳过短路的服务器和有高并发连接数的服务器

　　　　默认情况下RestClient最近3次无法与服务建立连接，会被置为短路状态。可以通过配置修改次数，具体可通过上述连接查看文档

　　③ WeightedResponseTimeRule

　　　　每个服务器根据其平均响应时间给予权重。响应时间越长，权重就越小。此规则随机选择服务器，其中可能性有服务器的权重决定

　　④ ZoneAvoidanceRule

　　　　以可用的服务器为基础，对服务器进行分类选择

　　④ BestAvailiableRuel

　　　　略短路的机器，并选择并发数较低的服务器

　　⑤ RandomRule

　　　　随机选择一个可用的服务器

　　⑥ RetryRule

　　　　重试机制的选择逻辑

2.自定义规则

　（1）默认轮询规则

import com.netflix.loadbalancer.BaseLoadBalancer;
import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.Server;

import java.util.ArrayList;
import java.util.List;

public class LoadBalancerTest {
    public static void main(String[] args) {
        ILoadBalancer loadBalancer = new BaseLoadBalancer();

        List<Server> servers = new ArrayList<>();
        servers.add(new Server("localhost", 8080));
        servers.add(new Server("localhost", 8081));

        loadBalancer.addServers(servers);

        for (int i = 0; i < 10; i++) {
           Server server =  loadBalancer.chooseServer(null);
           System.out.println(server);
        }

    }
}

　　（2）自定义规则

import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.Server;

import java.util.List;
import java.util.Random;

public class MyRule implements IRule {

    private ILoadBalancer iLoadBalancer;

    @Override
    public Server choose(Object o) {
        List<Server> servers = iLoadBalancer.getAllServers();

        Random random = new Random();
        int num = random.nextInt(10);
        if (num > 7) {
            return getServerByPort(servers, 8081);
        }
        return getServerByPort(servers, 8080);
    }

    @Override
    public void setLoadBalancer(ILoadBalancer iLoadBalancer) {
        this.iLoadBalancer = iLoadBalancer;
    }

    @Override
    public ILoadBalancer getLoadBalancer() {
        return this.iLoadBalancer;
    }

    private Server getServerByPort(List<Server> servers, int port) {
        for (Server server : servers) {
            if (server.getPort() == port) {
                return server;
            }
        }
        return null;
    }
}

import com.idelan.test.rules.MyRule;
import com.netflix.client.ClientFactory;
import com.netflix.client.http.HttpRequest;
import com.netflix.client.http.HttpResponse;
import com.netflix.config.ConfigurationManager;
import com.netflix.loadbalancer.BaseLoadBalancer;
import com.netflix.loadbalancer.Server;
import com.netflix.niws.client.http.RestClient;

import java.net.URI;
import java.util.ArrayList;
import java.util.List;

public class TestMyRule {

    public static void main(String[] args) throws Exception{
        //customRules();

        testRibbon();
    }

    //自定义负载均衡规则
    public static void customRules() {
        BaseLoadBalancer loadBalancer = new BaseLoadBalancer();
        MyRule rule = new MyRule();
        rule.setLoadBalancer(loadBalancer);
        loadBalancer.setRule(rule);

        List<Server> servers = new ArrayList<>();
        servers.add(new Server("localhost", 8080));
        servers.add(new Server("localhost", 8081));
        loadBalancer.addServers(servers);

        for (int i = 0; i < 10; i++) {
           Server server =  loadBalancer.chooseServer(null);
           System.out.println(server);
        }
    }

    //通过自定义负载均衡规则访问服务端接口
    public static void testRibbon() throws Exception{
        //通过properties配置文件导入配置信息
        //ConfigurationManager.loadPropertiesFromResources("my-ribbon.properties");

        //通过java代码导入配置信息
        ConfigurationManager.getConfigInstance().setProperty(
                "my-client.ribbon.listOfServers", "localhost:8080, localhost:8081");
        ConfigurationManager.getConfigInstance().setProperty("my-client.ribbon.NFLoadBalancerRuleClassName", MyRule.class.getName());

        RestClient client = (RestClient) ClientFactory.getNamedClient("my-client");
        HttpRequest request = HttpRequest.newBuilder().uri(new URI("/person")).build(); //
        for (int i = 0; i < 10; i++)  {
            HttpResponse response = client.executeWithLoadBalancer(request); //
            System.out.println("返回结果为 Status code for " + response.getRequestedURI() + "  :" + response.getStatus()+"内容："+response.getEntity(String.class));
        }
    }
}

说明：此处需要导入的jar包和上一篇博客（负载均衡框架 ribbon 一）中需要导入的jar包一样