【Spring Cloud】服务消费者

创建Spring Boot项目并添加依赖

创建项目过程略

添加依赖

<!-- 用于进行WEB开发，向外提供服务接口-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- 添加spring cloud eureka-client-->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

服务配置

• application.yml

  spring:
    application:
      name: service-consumer
  server:
    port: 8082
  eureka:
    client:
      service-url:
        defaultZone: http://localhost:8000/eureka/ //对应服务注册中心的配置，指定服务注册中心地址
  

• 启动类添加注解@EnableEurekaClient

  @EnableEurekaClient
  @SpringBootApplication
  public class ServiceProductApplication {
      @Bean
      public RestTemplate restTemplate() {
          return new RestTemplate();
      }
      
      public static void main(String[] args) {
          SpringApplication.run(ServiceProductApplication.class, args);
      }
  }
  

添加服务接口

Get /department/consumer (不推荐)

• 创建DepartmentController

  package com.example.serviceconsumer.controller;
  
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.beans.factory.annotation.Qualifier;
  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.PathVariable;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;
  import org.springframework.web.client.RestTemplate;
  
  @RestController
  @RequestMapping("/department")
  public class DepartmentController {
  
      @Autowired
      private RestTemplate restTemplate;
  
      @Autowired
      private LoadBalancerClient loadBalancerClient;
  
      @GetMapping("/consumer")
      public String getUser() {
          ServiceInstance serviceInstance = loadBalancerClient.choose("service-producter");
          // 客户端负载时请的URL 通过服务实例拼接的并对服务依赖太大，所以感觉不够友好
          String url = "http://" + serviceInstance.getHost() + ":" + serviceInstance.getPort() + "/user/123";
          return restTemplate.getForObject(url, String.class);
      }
  }
  

• 测试接口

  访问http://localhost:8082/consumer，返回结果如下

  name: gary, id: 123
  

Get /department/consumer /{id}(推荐)

• 修改主程序入口类
  添加注解@LoadBalanced

@EnableEurekaClient
@SpringBootApplication
public class ServiceConsumerApplication {
  
    @Bean("restTemplateWithLB")
    @LoadBalanced
    public RestTemplate restTemplateWithLB() {
        return new RestTemplate();
  }
  
    public static void main(String[] args) {
        SpringApplication.run(ServiceConsumerApplication.class, args);
    }
  }

• 修改DepartmentController

  package com.example.serviceconsumer.controller;
  
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.beans.factory.annotation.Qualifier;
  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.PathVariable;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;
  import org.springframework.web.client.RestTemplate;
  
  @RestController
  @RequestMapping("/department")
  public class DepartmentController {
  
    @Autowired
    @Qualifier("restTemplateWithLB")
    private RestTemplate restTemplateWithLB;
  
      @GetMapping("/consumer/{id}")
    public String getUserInfo(@PathVariable("id") String id) {
        // 此处只依赖于服务名称
        String url = "http://service-producter/user/" + id;
        return restTemplateWithLB.getForObject(url, String.class);
    }
  }

• 测试接口
  访问http://localhost:8082/consumer/666，返回结果如下

name: gary, id: 666