Ribbon支持多种客户端负载均衡算法，如轮询，最小响应时间，随机等等.

这里简单使用一下随机的Ribbon客户端负载均衡算法

使用上一章的项目，在spring-cloud-consumer-01项目中添加一个配置类，在里面构建一个随机负载均衡的bean

配置类的方式配置父子均衡算法

spring-cloud-consumer-01

消费端添加了对随机负载均衡的支持

LoadBarentConfig.java

package com.example.config;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;
@Configuration
public class LoadBarentConfig {

    /**
     * 随机规则
     * @param config
     * @return
     */
    @Bean
    public IRule iRuleBean(){
        return new RandomRule();
    }
}

特别注意

LoadBarentConfig不能被spring扫描器扫描到

所以LoadBarentConfig.java不能和SpringCloudConsumer01Application.java文件在同一级别或者下一级子目录中

SpringCloudConsumer01Application.java

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;

import com.example.config.LoadBarentConfig;
@EnableEurekaClient
@SpringBootApplication
@RibbonClient(name="spring-cloud-provider-test",configuration={LoadBarentConfig.class})
public class SpringCloudConsumer01Application {
    public static void main(String[] args) {
        SpringApplication.run(SpringCloudConsumer01Application.class, args);
    }
}

UserConstroller.java

package com.example.demo.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.example.demo.model.User;
@RestController
@RequestMapping(value="/user")
public class UserConstroller {
    @Autowired
    private RestTemplate restTemplate;
    @ResponseBody
    @GetMapping("/get")
    public User get(String uid){
        return restTemplate.getForObject("http://spring-cloud-provider/user/get?id="+uid, User.class);
    }

    @ResponseBody
    @GetMapping("/random_get")
    public User randomGet(String uid){
        return restTemplate.getForObject("http://spring-cloud-provider-test/user/get?id="+uid, User.class);
    }


}

spring-cloud-provider

这个服务包含spring-cloud-provider-01和spring-cloud-provider-02项目,这一组微服务提供的接口和前一节相同

spring-cloud-provider-test

这个服务包含spring-cloud-provider-03和spring-cloud-provider-04项目

spring-cloud-provider-03

package com.example.demo.controller;
import java.util.HashMap;
import java.util.Map;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import com.example.demo.model.User;

@RestController
@RequestMapping(value="/user")
public class UserController {
    private Map<String, User> umap = new HashMap();
    public UserController(){
        umap.put("1", new User("1", "xiaoming3", 30));
        umap.put("2", new User("2", "xiaohong3", 20));
        umap.put("3", new User("3", "zhangsan3", 80));
        umap.put("4", new User("4", "lisi3", 10));
        umap.put("5", new User("5", "wangwu3", 22));
    }
    @GetMapping(value="/get")
    @ResponseBody
    public User get(String id){
        return umap.get(id);
    }
}

spring-cloud-provider-04

package com.example.demo.controller;
import java.util.HashMap;
import java.util.Map;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import com.example.demo.model.User;

@RestController
@RequestMapping(value="/user")
public class UserController {
    private Map<String, User> umap = new HashMap();
    public UserController(){
        umap.put("1", new User("1", "xiaoming4", 30));
        umap.put("2", new User("2", "xiaohong4", 20));
        umap.put("3", new User("3", "zhangsan4", 80));
        umap.put("4", new User("4", "lisi4", 10));
        umap.put("5", new User("5", "wangwu4", 22));
    }
    @GetMapping(value="/get")
    @ResponseBody
    public User get(String id){
        return umap.get(id);
    }
}

验证

浏览器多次刷新http://192.168.88.101:9000/user/random_get?uid=1

内容随机显示

{"id":"1","userName":"xiaoming4","age":30,"birthday":null}
{"id":"1","userName":"xiaoming3","age":30,"birthday":null}

浏览器多次刷新http://192.168.88.101:9000/user/get?uid=1

内容轮询显示

{"id":"1","userName":"xiaoming","age":30,"birthday":null}
{"id":"1","userName":"xiaoming1","age":30,"birthday":null}

配置文件配置客户端负载均衡

推荐使用这种方式配置负载均衡

application.yaml

spring-cloud-provider-test: 
  ribbon: 
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule