Spring Cloud 2.x学习笔记：2、feign改进（Greenwich版本）

谁借莪１个温暖的怀抱￠ 2022-04-25 09:44 158阅读 0赞

### 1、Feign简介 ###

Feign 整合了ribbon，具有负载均衡的能力；Feign 采用的是基于接口的注解

### 2、新建模块 ###

新建一个服务消费者模块consumer-feign，代码结构如下图所示。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70]

#### 2.1 pom文件 ####

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <groupId>com.cntaiping.tpa</groupId>
        <artifactId>consumer-feign</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <packaging>jar</packaging>
        <name>consumer-feign</name>
        <description>Demo project for Spring Boot</description>
    
        <parent>
            <groupId>com.cntaiping.tpa</groupId>
            <artifactId>cloud</artifactId>
            <version>1.0-SNAPSHOT</version>
        </parent>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>
        </dependencies>
    
    </project>

#### 2.2 配置文件application.yml ####

eureka:
      client:
        serviceUrl:
          defaultZone: http://localhost:8800/eureka/
    server:
      port: 8500
    spring:
      application:
        name: consumer-feign

#### 2.3 启动类 ####

package com.cntaiping.tpa.consumerfeign;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.openfeign.EnableFeignClients;
    
    @SpringBootApplication
    @EnableFeignClients
    public class ConsumerFeignApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(ConsumerFeignApplication.class, args);
        }
    
    }

#### 2.4 服务消费类 ####

（1）Service层  
定义一个feign接口，通过@ FeignClient（“服务名”），来指定消费哪个服务。

package com.cntaiping.tpa.consumerfeign.service;
    
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    
    @FeignClient(value = "producer")
    public interface SchedualService {
        @RequestMapping(value = "/get",method = RequestMethod.GET)
        String hello(@RequestParam(value = "name") String name);
    }

（2）controller层

package com.cntaiping.tpa.consumerfeign.controller;
    
    import com.cntaiping.tpa.consumerfeign.service.SchedualService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class MessageController {
    
        @Autowired
        SchedualService schedualService;
    
        @GetMapping(value = "/hello")
        public String hello(@RequestParam String name) {
            return schedualService.hello( name );
        }
    }

#### 2.5 运行效果 ####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 1]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 2]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70]: /images/20220125/b0d94163e0774457bd25035b43bd9cef.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 1]: /images/20220125/12ff70c985804852aa0c28dda0cc9ad0.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5neXVxaWFuZw_size_16_color_FFFFFF_t_70 2]: /images/20220125/4bc4f633458f4723a5661047461b557f.png