Spring Cloud Alibaba 2.2 服务消费者(Feign)

电玩女神 2022-12-28 07:40 161阅读 0赞

### 文章目录 ###

*   *   *  1 摘要
         *  2 核心 Maven 依赖
         *  3 核心代码
         *   *  3.1 application 配置文件
             *  3.2 Service 层-服务调用
             *  3.3 Controller 控制层
             *  3.4 SpringBoot 启动类
             *  3.5 其他相关代码
         *  4 请求测试
         *   *  4.1 GET 方式请求接口
             *  4.2 POST 方式请求接口
         *  5 推荐参考资料
         *  6 Github 源码

### 1 摘要 ###

Feign 是微服务之间相互调用使用最广泛的工具，其内部集成了 Ribbon ，直接在接口上使用注解，极大地简化了微服务的调用过程。本文将介绍基于 Spring Cloud Alibaba 2.2 搭建使用 Feign 的服务消费者。

### 2 核心 Maven 依赖 ###

./cloud-alibaba-server-consumer-feign/pom.xml

<dependencies>
            
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
                <version>${spring-cloud-openfeign.version}</version>
            </dependency>
            
            
    
        </dependencies>
    
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>com.alibaba.cloud</groupId>
                    <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                    <version>${spring-cloud-alibaba.version}</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>

其中 `${spring-cloud-alibaba.version}` 的版本为 `2.2.3.RELEASE` , `${spring-cloud-openfeign.version}` 的版本为 `2.2.5.RELEASE`

**注意事项**: Spring Cloud Alibaba 2.2.3.RELEASE 版本支持的 Spring Boot 版本为 `2.3.1.RELEASE` ，建议在搭建项目时要保持版本的一致性，Spring Boot 版本过高或过低都可能导致不兼容问题

### 3 核心代码 ###

#### 3.1 application 配置文件 ####

./cloud-alibaba-server-consumer-feign/src/main/resources/application.yml

## config
    
    ## server
    server:
      port: 8604
    
    ## spring
    spring:
      application:
        name: cloud-alibaba-server-consumer-feign
      cloud:
        nacos:
          discovery:
            server-addr: 172.16.140.10:8688
    
    ## endpoint
    management:
      endpoints:
        web:
          exposure:
            include: "*"

简要配置说明:

`spring.application.name`: 应用名称，同时也是服务的名称

`spring.cloud.nacos.discovery.server-addr`: Nacos 服务的地址，包括 ip 和 端口，这里需要保证 Nacos 服务器的端口可访问

#### 3.2 Service 层-服务调用 ####

./cloud-alibaba-server-consumer-feign/src/main/java/com/ljq/demo/springboot/alibaba/server/consumer/feign/service/NacosConsumerService.java

package com.ljq.demo.springboot.alibaba.server.consumer.feign.service;
    
    import com.ljq.demo.springboot.alibaba.server.consumer.feign.common.constant.NacosConst;
    import com.ljq.demo.springboot.alibaba.server.consumer.feign.model.param.HelloParam;
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.cloud.openfeign.SpringQueryMap;
    import org.springframework.http.MediaType;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestBody;
    
    /** * @Description: Nacos 服务消费者业务层 * @Author: junqiang.lu * @Date: 2020/12/2 */
    @FeignClient(NacosConst.NACOS_SERVER_PROVIDER_NAME)
    public interface NacosConsumerService { 
    
        /** * hello * @param helloParam * @return */
        @GetMapping(value = "/api/nacos/hello", produces = { MediaType.APPLICATION_JSON_VALUE})
        ResponseEntity<String> hello(@SpringQueryMap HelloParam helloParam);
    
        /** * 回复 * * @param helloParam * @return */
        @PostMapping(value = "/api/nacos/replay", produces = { MediaType.APPLICATION_JSON_VALUE})
        ResponseEntity<String> replay(@RequestBody HelloParam helloParam);
    
    
    }

`@FeignClient` : Feign 客户端注解，用在接口上，`value/name` 属性用于指定请求服务的 ID

在接口中的方法上使用 Spring 的 `@RequestMapping/@GetMapping/@PostMapping`等注解，指定服务提供者的接口路径和请求方法

#### 3.3 Controller 控制层 ####

./cloud-alibaba-server-consumer-feign/src/main/java/com/ljq/demo/springboot/alibaba/server/consumer/feign/controller/NacosConsumerController.java

package com.ljq.demo.springboot.alibaba.server.consumer.feign.controller;
    
    import com.ljq.demo.springboot.alibaba.server.consumer.feign.model.param.HelloParam;
    import com.ljq.demo.springboot.alibaba.server.consumer.feign.service.NacosConsumerService;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.http.MediaType;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.*;
    
    /** * @Description: nacos 服务消费者控制层 * @Author: junqiang.lu * @Date: 2020/12/2 */
    @Slf4j
    @RestController
    @RequestMapping("/api/nacos/consumer")
    public class NacosConsumerController { 
    
        @Autowired
        private NacosConsumerService consumerService;
    
        @GetMapping(value = "/hello", produces = { MediaType.APPLICATION_JSON_VALUE})
        public ResponseEntity<String> hello(HelloParam helloParam) { 
            ResponseEntity<String> response = consumerService.hello(helloParam);
            log.info("response: {}", response.getBody());
            return response;
        }
    
        @PostMapping(value = "/replay", produces = { MediaType.APPLICATION_JSON_VALUE})
        public ResponseEntity<String> replay(@RequestBody HelloParam helloParam) { 
            ResponseEntity<String> response = consumerService.replay(helloParam);
            log.info("response: {}", response.getBody());
            return response;
        }
    
    
    }

#### 3.4 SpringBoot 启动类 ####

./cloud-alibaba-server-consumer-feign/src/main/java/com/ljq/demo/springboot/alibaba/server/consumer/feign/CloudAlibabaServerConsumerFeignApplication.java

package com.ljq.demo.springboot.alibaba.server.consumer.feign;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.openfeign.EnableFeignClients;
    
    /** * @author junqiang.lu */
    @EnableDiscoveryClient
    @EnableFeignClients
    @SpringBootApplication
    public class CloudAlibabaServerConsumerFeignApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(CloudAlibabaServerConsumerFeignApplication.class, args);
        }
    
    }

`@EnableFeignClients` ：启用 Feign 的注解

#### 3.5 其他相关代码 ####

常量类

./cloud-alibaba-server-consumer-feign/src/main/java/com/ljq/demo/springboot/alibaba/server/consumer/feign/common/constant/NacosConst.java

package com.ljq.demo.springboot.alibaba.server.consumer.feign.common.constant;
    
    /** * @Description: Nacos 相关常量 * @Author: junqiang.lu * @Date: 2020/12/2 */
    public class NacosConst { 
    
        private NacosConst() { 
        }
    
        public static final String NACOS_SERVER_PROVIDER_NAME = "cloud-alibaba-server-provider";
    }

请求参数接收类

./cloud-alibaba-server-provider/src/main/java/com/ljq/demo/pringboot/alibaba/server/provider/model/param/HelloParam.java

package com.ljq.demo.pringboot.alibaba.server.provider.model.param;
    
    import lombok.Data;
    
    import java.io.Serializable;
    
    /** * @Description: 用户实体类 * @Author: junqiang.lu * @Date: 2020/12/2 */
    @Data
    public class HelloParam implements Serializable { 
    
        private static final long serialVersionUID = 2958405318099108563L;
    
        /** * 用户名 */
        private String name;
    }

### 4 请求测试 ###

依次启动服务提供者项目 `cloud-alibaba-server-provider`，服务消费者项目 `cloud-alibaba-server-consumer-feign`

打开 Nacos 控制台，可以看到两个服务

![Nacos 控制台][Nacos]

请求服务消费者的接口

#### 4.1 GET 方式请求接口 ####

接口地址与请求参数:

http://127.0.0.1:8604/api/nacos/consumer/hello?name=%E5%BE%B7%E7%8E%9B%E8%A5%BF%E4%BA%9A

请求方式: GET

返回结果:

Hello,德玛西亚

服务消费者日志:

2020-12-15 15:30:20.457  INFO 76432 --- [nio-8604-exec-1] .l.d.s.a.s.c.f.c.NacosConsumerController : response: Hello,德玛西亚

服务提供者日志:

2020-12-15 15:30:20.353  INFO 76411 --- [nio-8600-exec-1] c.l.d.p.a.s.p.c.NacosProviderController  : serverPort: 8600
    2020-12-15 15:30:20.353  INFO 76411 --- [nio-8600-exec-1] c.l.d.p.a.s.p.c.NacosProviderController  : result: Hello,德玛西亚

#### 4.2 POST 方式请求接口 ####

接口地址:

http://127.0.0.1:8604/api/nacos/consumer/replay

请求参数:

{ 
        "name": "卢本伟"
    }

请求方式: POST

返回结果:

Hi,卢本伟,I'm fine,Thank you.

服务消费者日志:

2020-12-15 15:31:26.906  INFO 76432 --- [nio-8604-exec-3] .l.d.s.a.s.c.f.c.NacosConsumerController : response: Hi,卢本伟,I'm fine,Thank you.

服务提供者日志:

2020-12-15 15:31:26.904  INFO 76411 --- [nio-8600-exec-3] c.l.d.p.a.s.p.c.NacosProviderController  : result: Hi,卢本伟,I'm fine,Thank you.

至此，一个基于 Spring Cloud Alibaba 2.2 使用 Feign 的服务消费者框架已经搭建完成

### 5 推荐参考资料 ###

[Spring Cloud Alibaba系列教程 - Spring Cloud Alibaba 创建服务消费者(Feign)][Spring Cloud Alibaba_ - Spring Cloud Alibaba _Feign]

### 6 Github 源码 ###

**Gtihub 源码地址** : [https://github.com/Flying9001/springBootDemo][https_github.com_Flying9001_springBootDemo]

个人公众号:**404Code**,分享半个互联网人的技术与思考，感兴趣的可以关注.  
![404Code][]

[Nacos]: /images/20221120/7091437cf3464b1ab0d4becec008214e.png
[Spring Cloud Alibaba_ - Spring Cloud Alibaba _Feign]: https://www.jianshu.com/p/ff9480117b82
[https_github.com_Flying9001_springBootDemo]: https://github.com/Flying9001/springBootDemo
[404Code]: /images/20221120/137f809e6b6c45bbbb8027532469633e.png