SpringCloud组件三之Feign-服务消费（G版本）

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

@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/> <!-- lookup parent from repository -->
    </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

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();
    }
}