Spring Cloud Alibaba 02_使用 ribbon 实现负载均衡

客官°小女子只卖身不卖艺 2022-12-16 13:01 138阅读 0赞

**Spring Cloud Alibaba 02\_使用 ribbon 实现负载均衡**

注：Ribbon 是 Netflix 提供的组件，不是 Alibaba 的组件

*  **修改 ConsumerConfiguration，添加 @LoadBalanced 注解**

package com.blu.configuration;
    
    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 ConsumerConfiguration { 
    
        @Bean
        @LoadBalanced
        public RestTemplate restTemplate(){ 
            return new RestTemplate();
        }
    
    }

*  **修改 ConsumerController 中的 index 方法：**

**Ribbon会将服务名 provider 解析为相应的 uri**

@GetMapping("index")
    public String index(){ 
    	String result = restTemplate.getForObject("http://provider/index", String.class);
        return "调用的端口为："+ result;
    }

*  **启动访问：[http://localhost:8100/index][http_localhost_8100_index]**

**这里的负载均衡策略默认是轮询**

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JMVV8xMTE_size_16_color_FFFFFF_t_70_pic_left]  
**修改负载均衡策略**

*  **随机算法：**

只需修改配置文件即可：

server:
      port: 8100
    
    provider:
      ribbon:
        NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule

*  **基于权重的算法：**

添加 NacosWeightedRule 类

package com.blu.configuration;
    
    import com.alibaba.cloud.nacos.NacosDiscoveryProperties;
    import com.alibaba.cloud.nacos.ribbon.NacosServer;
    import com.alibaba.nacos.api.exception.NacosException;
    import com.alibaba.nacos.api.naming.NamingService;
    import com.alibaba.nacos.api.naming.pojo.Instance;
    import com.netflix.client.config.IClientConfig;
    import com.netflix.loadbalancer.AbstractLoadBalancerRule;
    import com.netflix.loadbalancer.BaseLoadBalancer;
    import com.netflix.loadbalancer.ILoadBalancer;
    import com.netflix.loadbalancer.Server;
    import org.springframework.beans.factory.annotation.Autowired;
    
    public class NacosWeightedRule extends AbstractLoadBalancerRule { 
    
        @Autowired
        private NacosDiscoveryProperties nacosDiscoveryProperties;
    
        @Override
        public void initWithNiwsConfig(IClientConfig clientConfig) { 
            //读取配置文件
        }
    
        @Override
        public Server choose(Object key) { 
            ILoadBalancer loadBalancer = this.getLoadBalancer();
            BaseLoadBalancer baseLoadBalancer = (BaseLoadBalancer) loadBalancer;
            //获取要请求的服务名
            String name = baseLoadBalancer.getName();
            //获取服务发现的相关API
            NamingService namingService = nacosDiscoveryProperties.namingServiceInstance();
            try{ 
                Instance instance = namingService.selectOneHealthyInstance(name);
                return new NacosServer(instance);
            } catch (NacosException e) { 
                e.printStackTrace();
                return null;
            }
    
        }
    }

修改配置文件，指定负载均衡策略的类：

server:
      port: 8100
    
    provider:
      ribbon:
        NFLoadBalancerRuleClassName: com.blu.configuration.NacosWeightedRule

可在 nacos 中修改指定实例的权重：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JMVV8xMTE_size_16_color_FFFFFF_t_70_pic_left 1]

[http_localhost_8100_index]: http://localhost:8100/index
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JMVV8xMTE_size_16_color_FFFFFF_t_70_pic_left]: /images/20221123/dc22fa07679849079d09f085dff627cf.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JMVV8xMTE_size_16_color_FFFFFF_t_70_pic_left 1]: /images/20221123/9b5282a04dd14db090eeeea246be1192.png