springcloud-Ribbon 客户端负载均衡技术

ribbon：是一个实现负载均衡的客户端组件

ribbon和eureka整合之后，客户端直接调用，不用关心ip地址。

负载均衡：讲用户的请求分摊到众多服务器，提到效率

客户端微服务：pom.xml

<!--        eureka配置-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
            <version>1.4.7.RELEASE</version>
        </dependency>

<!--        ribbon-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
            <version>1.4.7.RELEASE</version>
        </dependency>

eureka client开启

使用注解  @EnableEurekaClient

package com.wang.springcloud;


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

@SpringBootApplication
@EnableEurekaClient
public class DeptConsumer {
    public static void main(String[] args) {
        SpringApplication.run(DeptConsumer.class,args);
    }
}

配置修改

server:
  port: 80


eureka:
  client:
    register-with-eureka: false  #不像eureka 注册自己
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/

负载均衡开启

导入ribbon依赖之后，可以通过注解开启负载均衡

@LoadBalanced 开启负载均衡

package com.wang.springcloud.config;


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 ConfigBean {


    @Bean
    //    配置负载均衡请求
    @LoadBalanced  //Ribbon
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
    
}

controller 访问服务的url变动

之前是写死，直接访问服务提供端的url,ribbon 之后，使用服务名称，ribbon自己根据服务名称路由对应可用的服务，通过eureka访问。

private  static final String REST_URL_PREFIX = "http://SPRINGCLOUD-PROVIDER-DEPT" ;

package com.wang.springcloud.controller;


import com.wang.springcloud.pojo.Dept;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.xml.crypto.KeySelector;
import java.util.List;


@RestController
public class DeptConsumerController {

    //消费者，不应该有service层
    //RestTemplate

    @Autowired
    private RestTemplate restTemplate;
    //访问服务端url  这里写死的，做不到负载均衡效果
//    private  static final String REST_URL_PREFIX = "http://localhost:8001" ;
//    由于之前已经通过eureka实现服务的集群，这里通过服务名访问

    private  static final String REST_URL_PREFIX = "http://SPRINGCLOUD-PROVIDER-DEPT" ;

    @RequestMapping("/consumer/dept/add")
    public boolean add(Dept dept){
        //参数1：url
        //参数2: post方式,请求入参
        //参数3：返回类型
        return restTemplate.postForObject(REST_URL_PREFIX+"/dept/add",dept,Boolean.class);
    }

    @RequestMapping("/consumer/dept/get/{id}")
    public Dept get(@PathVariable("id") int id){
        return restTemplate.getForObject(REST_URL_PREFIX+"/dept/get/"+id,Dept.class);
    }


    @RequestMapping("/consumer/dept/list")
    public List<Dept> queryAll(){
        return restTemplate.getForObject(REST_URL_PREFIX+"/dept/list",List.class);
    }


}

测试：

通过客户端访问