SpringCloud-rest+ribbon

Ribbon简介

ribbon
在微服务架构中，业务都会被拆分成一个独立的服务，服务与服务的通讯是基于http restful的。Spring cloud有两种服务调用方式，一种是ribbon+restTemplate，另一种是feign。在这一篇文章首先讲解下基于ribbon+rest;
ribbon是一个负载均衡客户端，可以很好的控制htt和tcp的一些行为。Feign默认集成了ribbon.

Ribbon使用

创建工程

1.Cloud Discovery>>Eureka Discovery工程

2.pom.xml中添加web依赖：

  <!--web-->
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
  </dependency>

  <!--不写getter/setter的插件-->
  <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
  </dependency>

3.启动类添加@EnableEurekaClient注解：

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

4.application.yml配置文件配置服务注册地址：

  eureka:
    client:
      service-url:
        defaultZone: http://172.96.251.101:8761/eureka
  spring:
    application:
      name: service-Ribbon
            #service-restTemplate-Ribbon
  
  ##更改ribbon默认的负载均衡方式（默认是轮循，改为随机）
  ##WXPROJECT：目标应用的名称
  #WXPROJECT:
  #  ribbon:
  #    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule
  
  server:
    port: 8084

5.依然调用WXPROJECT这个服务的productInfo方法，所以创建实体类Product.java

    @Data
      public class Product {
      
          private String productId;
          private String productName;
          private BigDecimal productPrice;
          private Integer productStock;
          private String productDescription;
          private String productIcon;
          private String productStatus;
          private String categoryType;
          private Date createTime;
          private Date updateTime;    
      }

6.创建RestTemplateConfig.java

  package com.ux.resttemplateribbon.restTemplateConfig;

  import org.springframework.cloud.client.loadbalancer.LoadBalanced;
  import org.springframework.context.annotation.Bean;
  import org.springframework.stereotype.Component;
  import org.springframework.web.client.RestTemplate;
  
  @Component
  public class RestTemplateConfig {
  
      @Bean
      @LoadBalanced
      public RestTemplate restTemplate() {
          return new RestTemplate();
      }
  }

7.利用RestTeamlate+LoadBalanced注解实现对远程服务的调用：

  package com.ux.resttemplateribbon.controller;

  import com.ux.resttemplateribbon.pojo.Product;
  import lombok.extern.slf4j.Slf4j;
  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.RequestParam;
  import org.springframework.web.bind.annotation.RestController;
  import org.springframework.web.client.RestTemplate;
  
  /**
   * 利用RestTeamlate+LoadBalanced注解实现对远程服务的调用：
   * **************@Bean
   * **************@LoadBalanced public RestTemplate restTemplate() {
   * **************return new RestTemplate();
   * **************}
   * <p>
   * <p>
   * 本质依然是RestTeamlate+loadBalancerClient
   */
  
  @Slf4j
  @RestController
  @RequestMapping("/client/product")
  public class ProductController {
  
      @Autowired
      RestTemplate restTemplate;
  
      @GetMapping("/info")
      public Product info(@RequestParam("productId") String productId) {
  
          Product result = restTemplate.getForObject("http://WXPROJECT/product/productInfo?productId=" + productId, Product.class);
  
          log.info("~~~~~Product={}", result);
          return result;
      }
  }

小结

利用RestTeamlate+LoadBalanced注解实现对远程服务的调用本质依然是RestTeamlate+loadBalancerClient，RestTeamlate+loadBalancerClient调用方式如下，不需要单独写RestTemplateConfig.java了：

  package com.ux.resttemplateribbon.controller;

  import com.ux.resttemplateribbon.pojo.Product;
  import lombok.extern.slf4j.Slf4j;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.cloud.client.ServiceInstance;
  import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RequestParam;
  import org.springframework.web.bind.annotation.RestController;
  import org.springframework.web.client.RestTemplate;
  
  /**
   * restTeamlate+loadBalancerClient(根据服务名称获取host和端口构造成url)实现服务之间的请求调用
   */
  
  @Slf4j
  @RestController
  @RequestMapping("/client/product")
  public class ProductController2 {
  
      @Autowired
      LoadBalancerClient loadBalancerClient;
  
      @GetMapping("/info2")
      public Product info(@RequestParam("productId") String productId) {
  
          RestTemplate restTemplate = new RestTemplate();
          //根据服务名称获取服务信息
          ServiceInstance instance = loadBalancerClient.choose("WXPROJECT");
          //获取服务端口
          Integer port = instance.getPort();
          //获取服务host
          String host = instance.getHost();
          //构造（拼接）url  形式为：http://192.168.1.102:8081/product/productInfo?productId=11
          String url = String.format("http://%s:%s", host, port + "/product/productInfo?productId=" + productId);
          Product result = restTemplate.getForObject(url, Product.class);
          //Product result = restTemplate.getForObject("http://WXPROJECT/product/productInfo?productId="+productId, Product.class);
          log.info("~~~~~Product={}", url);
          return result;
      }
  }