Feign是一个声明式的Web服务客户端。能很简单的调用其他服务的API。并且实现负载均衡。
1、创建Feign模块
在前两篇文章的基础上继续改造工程。
Spring Cloud 之 服务注册与发现 Eureka组件
Spring Cloud 之 负载均衡 Ribbon组件
新建model:service-feign
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.server</groupId>
<artifactId>feign</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>feign</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>com.cloud</groupId>
<artifactId>test</artifactId>
<version>1.0-SNAPSHOT</version>
</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.RELEASE</spring-cloud.version>
</properties>
<dependencies>
<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>
</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>
配置文件application.yml
eureka:
client:
serviceUrl:
# 注明自己的服务注册中心的地址
defaultZone: http://localhost:7777/eureka/
server:
port: 8005
spring:
application:
name: service-feign
在应用主类上表明为eureka-client,向服务注册中心注册
@SpringBootApplication
@EnableEurekaClient
//注解开启Feign
@EnableFeignClients
public class FeignApplication {
public static void main(String[] args) {
SpringApplication.run(FeignApplication.class, args);
}
}
创建调用接口FeignService
@Service
@FeignClient(value = "service-hello")
public interface FeignService {
@RequestMapping(value = "/hi",method = RequestMethod.GET)
String sayHiFromClientOne(@RequestParam(value = "name") String name);
}
@FeignClient(value = “service-hello”),value 指明要调用的服务名
Controller
@RestController
public class HiController {
@Autowired
FeignService feignService;
@RequestMapping(value = "/hi", method = RequestMethod.GET)
public String sayHi(@RequestParam String name) {
return feignService.sayHiFromClientOne(name);
}
}
2、测试
启动service-feign
可以再服务注册中心看到实例:
浏览器多次访问:http://localhost:8005/hi?name=mistra,会交替出现
- hi mistra,i am from port:8002
- hi mistra,i am from port:8003
service-feign远程调用了eureka-client的服务,并且实现了负载均衡。