springcloud(Brixton版) EurekaServer Feign

柔情只为你懂 2023-08-17 16:26 88阅读 0赞

序：Feign集成了Ribbon。Ribbon+eureka是面向微服务编程，而Feign是面向接口编程。

Ribbon  
是一个基于 HTTP 和 TCP 客户端 的负载均衡的工具。  
它可以 在客户端 配置 RibbonServerList（服务端列表），使用 HttpClient 或 RestTemplate 模拟http请求，步骤相当繁琐。

Feign  
Feign 是在 Ribbon的基础上进行了一次改进，是一个使用起来更加方便的 HTTP 客户端。

采用接口的方式， 只需要创建一个接口，然后在上面添加注解即可 ，将需要调用的其他服务的方法定义成抽象方法即可， 不需要自己构建http请求。

然后就像是调用自身工程的方法调用，而感觉不到是调用远程方法，使得编写 客户端变得非常容易。

1.创建springboot项目

2.pom.xml

<?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.didispace</groupId>
       <artifactId>eureka-feign</artifactId>
       <version>1.0.0</version>
       <packaging>jar</packaging>
    
       <name>eureka-feign</name>
       <description>Spring Cloud project</description>
    
       <parent>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-parent</artifactId>
          <version>1.3.5.RELEASE</version>
          <relativePath/> 
       </parent>
    
       <properties>
          <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
          <java.version>1.8</java.version>
       </properties>
    
       <dependencies>
          <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-feign</artifactId>
          </dependency>
          <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-eureka</artifactId>
          </dependency>
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
          </dependency>
    
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
          </dependency>
       </dependencies>
    
       <dependencyManagement>
          <dependencies>
             <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Brixton.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
             </dependency>
          </dependencies>
       </dependencyManagement>
    
       <build>
          <plugins>
             <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
             </plugin>
          </plugins>
       </build>
    
    </project>

3.application.properties

spring.application.name=feign-consumer
    server.port=4444
    
    eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka/

4.feign service

import org.springframework.cloud.netflix.feign.FeignClient;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    
    @FeignClient("compute-service") //这里指定所掉接口所在的服务的微服务名称
    public interface ComputeClient {
    
        @RequestMapping(method = RequestMethod.GET, value = "/add") //这就是对应的微服务里面的具体的add的方法
        Integer add(@RequestParam(value = "a") Integer a, @RequestParam(value = "b") Integer b);
    
    }

5.controller

import com.didispace.service.ComputeClient;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class ConsumerController {
    
        @Autowired
        ComputeClient computeClient;
    
        @RequestMapping(value = "/add", method = RequestMethod.GET)
        public Integer add() {
            return computeClient.add(10, 20);
        }
    
    }

6.启动类

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.netflix.feign.EnableFeignClients;
    
    @SpringBootApplication
    @EnableDiscoveryClient
    @EnableFeignClients
    public class FeignApplication {
    
       public static void main(String[] args) {
          SpringApplication.run(FeignApplication.class, args);
       }
    
    }

7.访问：[http://localhost:1111/][http_localhost_1111]

![20190928174039818.png][]

[http://192.168.8.1:4444/add][http_192.168.8.1_4444_add]

![20190928174056930.png][]

这样就调用了计算服务的add的方法。

[http_localhost_1111]: http://localhost:1111/
[20190928174039818.png]: /images/20230810/d43116c5411240db9e572342b487358c.png
[http_192.168.8.1_4444_add]: http://192.168.8.1:4444/add
[20190928174056930.png]: /images/20230810/1afabffb071d47a3aba18155601a2e16.png