SpringCloud从入门到精通——本地负载均衡算法

r囧r小猫 2023-09-29 11:23 91阅读 0赞

## 本地负载均衡算法 ##

#### 目录 ####

*  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 {
        
        /**
         * 负载均衡算法：给我多个地址，负载均衡会取出一个地址返回使用
         * @param serviceId
         * @return
         */
        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;
    
    /**
     * @Author: JYC
     * @Title: RoundLoadBalance
     * @Description: TODO
     * @Date: 2022/4/22 11:23
     */
    @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<ServiceInstance> 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;
    
    /**
     * @Author: JYC
     * @Title: OrderToMemberService
     * @Description: TODO
     * @Date: 2022/4/21 14:04
     */
    @RestController
    public class OrderToMemberService {
        
        @Autowired
        private DiscoveryClient discoveryClient;
        @Autowired
        private RoundLoadBalance roundLoadBalance;
    
        /**
         * 订单服务，调用 会员服务接口
         */
        @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";
            /**
             * 根据服务名称，从注册中心获取会员的接口地址
             */
    //        List<ServiceInstance> 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.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;
    
    /**
     * @Author: JYC
     * @Title: RandomLoadBalance
     * @Description: TODO
     * @Date: 2022/4/22 11:37
     */
    @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<ServiceInstance> 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;
    
    /**
     * @Author: JYC
     * @Title: OrderToMemberService
     * @Description: TODO
     * @Date: 2022/4/21 14:04
     */
    @RestController
    public class OrderToMemberService {
        
        @Autowired
        private DiscoveryClient discoveryClient;
        @Autowired
        private RoundLoadBalance roundLoadBalance;
        @Autowired
        private RandomLoadBalance randomLoadBalance;
    
        /**
         * 订单服务，调用 会员服务接口
         */
        @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";
            /**
             * 根据服务名称，从注册中心获取会员的接口地址
             */
    //        List<ServiceInstance> 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;
    
    /**
     * @Author: JYC
     * @Title: OrderToMemberService
     * @Description: TODO
     * @Date: 2022/4/21 14:04
     */
    @RestController
    @Slf4j
    public class OrderToMemberService {
        
        @Autowired
        private DiscoveryClient discoveryClient;
    
        /**
         * 订单服务，调用 会员服务接口
         */
        @RequestMapping("/orderToMember")
        public String OrderToMember() {
        
            /**
             * 根据服务名称，从注册中心获取会员的接口地址
             */
            List<ServiceInstance> 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;
    
    /**
     * @Author: JYC
     * @Title: WeightLoadBalance
     * @Description: TODO
     * @Date: 2022/4/22 14:38
     */
    @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<ServiceInstance> instances = discoveryClient.getInstances(serviceId);
            if (instances == null) {
        
                return null;
            }
    
            List<ServiceInstance> 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;
    
    /**
     * @Author: JYC
     * @Title: OrderToMemberService
     * @Description: TODO
     * @Date: 2022/4/21 14:04
     */
    @RestController
    @Slf4j
    public class OrderToMemberService {
        
        @Autowired
        private DiscoveryClient discoveryClient;
        @Autowired
        private WeightLoadBalance weightLoadBalance;
    
        /**
         * 订单服务，调用 会员服务接口
         */
        @RequestMapping("/orderToMember")
        public String OrderToMember() {
        
            /**
             * 根据服务名称，从注册中心获取会员的接口地址
             */
    //        List<ServiceInstance> 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);
        }
    }

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