SpringCloud 学习 | 第四篇： 服务消费者 feign

Feign介绍

Feign是一个声明式的web service客户端，它使得编写web service客户端更为容易。创建接口，为接口添加注解，即可使用Feign。Feign可以使用Feign注解或者JAX-RS注解，还支持热插拔的编码器和解码器。Spring Cloud为Feign添加了Spring MVC的注解支持，并整合了Ribbon和Eureka来为使用Feign时提供负载均衡。译自：http://projects.spring.io/spring-cloud/docs/1.0.3/spring-cloud.html#spring-cloud-feign创建springboot应用pom.xml如下<?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.example</groupId>
<artifactId>service_feign</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>service_feign</name>
<description>Demo project for Spring Boot</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Finchley.M8</spring-cloud.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</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>
</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>

<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>

</project>配置文件application.ymleureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/,http://localhost:8760/eureka/ server:
port: 8765

spring:
application:
name: service_feign编辑启动类添加@EnableFeignClients 开启feign@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
//使用EnableFeignClients 开启Feign
public class ServiceFeignApplication {

public static void main(String[] args) {
SpringApplication.run(ServiceFeignApplication.class, args);
}
}测试接口//通过@ FeignClient（“服务名”），来指定调用哪个服务。比如在代码中调用了service-hi服务的“/hi”接口，还可以使用url参数指定一个URL
@FeignClient(value = "SUPPLY-HI")
public interface HiSend {

@RequestMapping(value = "/hi",method = RequestMethod.GET)
String sayHiFromClientOne(@RequestParam(value = "name") String name);//添加参数name 相当于/hi?name=xxx
}controller类@RestController
public class HiController {

@Autowired
HiSend hiSend;
@RequestMapping(value = "/hi",method = RequestMethod.GET)
public String sayHi(String name){
return hiSend.sayHiFromClientOne(name);
}
}测试 多次请求http://localhost:8765/hi?name=forezp 



至此，服务消费者 feign编写完成且实现了均衡负载。