SpringCloud从入门到精通——本地负载均衡算法

本地负载均衡算法

本地负载均衡算法
- 1. 轮询算法
- 2. 随机算法
- 3. 故障转移算法
- 4. 权重算法

1. 轮询算法

package com.demo.loadbalance;

import org.springframework.cloud.client.ServiceInstance;

public interface LoadBalance {
    
    ServiceInstance getInstances(String serviceId);
}

package com.demo.loadbalance;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;


@Component
public class RoundLoadBalance implements LoadBalance {
    @Autowired
    private DiscoveryClient discoveryClient;
    private AtomicInteger atomicCount = new AtomicInteger(0);

    @Override
    public ServiceInstance getInstances(String serviceId) {
        // 1. 根据服务的名称，获取该服务集群地址列表
        List instances = discoveryClient.getInstances(serviceId);
        // 2. 判断是否为null
        if (instances == null || instances.size() == 0) {
            return  null;
        }
        // 3. 使用负载均衡算法
        int index = atomicCount.incrementAndGet();
        return instances.get(index);
    }
}

package com.demo.service;

import com.demo.loadbalance.RoundLoadBalance;
import com.demo.utils.HttpClientUtils;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;


@RestController
public class OrderToMemberService {
    @Autowired
    private DiscoveryClient discoveryClient;
    @Autowired
    private RoundLoadBalance roundLoadBalance;

    
    @RequestMapping("/orderToMember")
    public String OrderToMember() {
        // HttpClient 工具类 实现RPC远程调用
//        String memberUrl = "http://192.168.66.1:8080/getMember";
        
//        List instances = discoveryClient.getInstances("demo-member");
//        ServiceInstance serviceInstance = instances.get(0);
        ServiceInstance serviceInstance = roundLoadBalance.getInstances("demo-member");
        // 会员服务的ip和端口
        String memberUrl = "http://" + serviceInstance.getHost() + ":" + serviceInstance.getPort() + "/" + "getMember";
        return "订单服务调用会员服务：" + HttpClientUtils.doGet(memberUrl, null);
    }
}

2. 随机算法

package com.demo.loadbalance;

import org.springframework.cloud.client.ServiceInstance;

public interface LoadBalance {
    
    ServiceInstance getInstances(String serviceId);
}

package com.demo.loadbalance;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.stereotype.Component;

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


@Component
public class RandomLoadBalance implements LoadBalance{
    @Autowired
    private DiscoveryClient discoveryClient;


    @Override
    public ServiceInstance getInstances(String serviceId) {
        // 1. 根据服务的名称，获取该服务集群地址列表
        List instances = discoveryClient.getInstances(serviceId);
        // 2. 判断是否为null
        if (instances == null || instances.size() == 0) {
            return  null;
        }
        // 生成随机数范围
        Random random = new Random();
        int index = random.nextInt(instances.size());
        return instances.get(index);
    }
}

package com.demo.service;

import com.demo.loadbalance.RandomLoadBalance;
import com.demo.loadbalance.RoundLoadBalance;
import com.demo.utils.HttpClientUtils;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;


@RestController
public class OrderToMemberService {
    @Autowired
    private DiscoveryClient discoveryClient;
    @Autowired
    private RoundLoadBalance roundLoadBalance;
    @Autowired
    private RandomLoadBalance randomLoadBalance;

    
    @RequestMapping("/orderToMember")
    public String OrderToMember() {
        // HttpClient 工具类 实现RPC远程调用
//        String memberUrl = "http://192.168.66.1:8080/getMember";
        
//        List instances = discoveryClient.getInstances("demo-member");
//        ServiceInstance serviceInstance = instances.get(0);
//        ServiceInstance serviceInstance = roundLoadBalance.getInstances("demo-member");
        ServiceInstance serviceInstance = randomLoadBalance.getInstances("demo-member");
        // 会员服务的ip和端口
        String memberUrl = "http://" + serviceInstance.getHost() + ":" + serviceInstance.getPort() + "/" + "getMember";
        return "订单服务调用会员服务：" + HttpClientUtils.doGet(memberUrl, null);
    }
}

3. 故障转移算法

package com.demo.service;

import com.demo.loadbalance.RandomLoadBalance;
import com.demo.loadbalance.RoundLoadBalance;
import com.demo.utils.HttpClientUtils;
import lombok.extern.slf4j.Slf4j;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;


@RestController
@Slf4j
public class OrderToMemberService {
    @Autowired
    private DiscoveryClient discoveryClient;

    
    @RequestMapping("/orderToMember")
    public String OrderToMember() {
        
        List instances = discoveryClient.getInstances("demo-member");
        for (int i = 0; i < instances.size(); i++) {
            try {
                ServiceInstance serviceInstance = instances.get(i);
                // 会员服务的ip和端口
                String memberUrl = "http://" + serviceInstance.getHost() + ":" + serviceInstance.getPort() + "/" + "getMember";
            }catch (Exception e) {
                log.error("[rpc远程调用发生了故障，开始故障转移，切换下一个地址调用 e:{}]", e);
            }
        }
        return "fail";
    }
}

4. 权重算法

package com.demo;

import com.demo.loadbalance.LoadBalance;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.stereotype.Component;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;


@Component
public class WeightLoadBalance implements LoadBalance {
    @Autowired
    private DiscoveryClient discoveryClient;
    private AtomicInteger countAtomicInteger = new AtomicInteger(0);

    @Override
    public ServiceInstance getInstances(String serviceId) {
        // 1.根据服务Id名称，获取该接口多个实例
        List instances = discoveryClient.getInstances(serviceId);
        if (instances == null) {
            return null;
        }

        List newInstances = new ArrayList<>();
        // 循环遍历该服务名称，对应的多个实例
        instances.forEach((service) -> {
            // 获取该服务实例对应的权重比例
            Double weight = Double.parseDouble(service.getMetadata().get("nacos.weight"));
            for (int i = 0; i < weight; i++) {
                newInstances.add(service);
            }
        });
        // 线程安全
        return newInstances.get(countAtomicInteger.incrementAndGet() % newInstances.size());
    }
}

package com.demo.service;

import com.demo.WeightLoadBalance;
import com.demo.loadbalance.RandomLoadBalance;
import com.demo.loadbalance.RoundLoadBalance;
import com.demo.utils.HttpClientUtils;
import lombok.extern.slf4j.Slf4j;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;


@RestController
@Slf4j
public class OrderToMemberService {
    @Autowired
    private DiscoveryClient discoveryClient;
    @Autowired
    private WeightLoadBalance weightLoadBalance;

    
    @RequestMapping("/orderToMember")
    public String OrderToMember() {
        
//        List instances = discoveryClient.getInstances("demo-member");
//        ServiceInstance serviceInstance = instances.get(0);
        ServiceInstance serviceInstance = weightLoadBalance.getInstances("demo-member");
        // 会员服务的ip和端口
        String memberUrl = "http://" + serviceInstance.getHost() + ":" + serviceInstance.getPort() + "/" + "getMember";
        return "订单服务调用会员服务：" + HttpClientUtils.doGet(memberUrl, null);
    }
}

SpringCloud从入门到精通——本地负载均衡算法

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