SpringCloud组件三之Feign-服务消费（G版本）

ゝ一纸荒年。 2022-02-20 07:25 191阅读 0赞

## 1. 服务消费 ##

SpringCloud组件中服务消费组件有二：Ribbon和Feign。在上一篇中讲解了如何使用Ribbon，现在讲解如何去使用Feign。

## 2.现状 ##

我们有一个注册中心（resitry），一个服务提供者（provider），provider中编写一个接口/hello  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMDA4NTM1_size_16_color_FFFFFF_t_70]

@RestController
    public class TsetController { 
    
        @GetMapping("hello")
        public String hello(){ 
            return "hello";
        }
    }

## 3.注册服务（Feign） ##

新建项目Feign：new module → SpringBoot项目 → 添加相应组件 web+Eureka+Feign  
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>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.4.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>cn.lll</groupId>
        <artifactId>feign</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>feign</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
            <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.4</version>
            </dependency>
        </dependencies>
    
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>${ spring-cloud.version}</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>

启动类

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

yml文件配置

server:
      port: 8083
    spring:
      application:
        name: feign-server
    eureka:
      client:
        service-url:
          defaultZone: http://127.0.0.1:10010/eureka

## 4.添加Feign服务 ##

添加注释：@EnableFeignClients

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

编写一个Client和Controller  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMDA4NTM1_size_16_color_FFFFFF_t_70 1]  
HelloClient

@FeignClient(value = "SERVER-PROVIDER")
    public interface HelloClient { 
    	
        @GetMapping("hello")
        String hello();
    }

HelloController

@RestController
    @Slf4j
    public class HelloController { 
        @Autowired
        private HelloClient hello;
    
        @GetMapping("hello")
        public String sayHello(){ 
            String str = "8083端口正在被调用:";
            log.info(str);
            return str+hello.hello();
        }
    }

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