Spring Cloud之Feign

Feign集合了Ribbon和Hystrix，封装了RestTemplate，用于远程服务调用，可存在于任一客户端。话不多说，上代码。
新建一个spring-cloud-feign工程：
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.example</groupId>
    <artifactId>spring-cloud-feign</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-cloud-feign</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.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>Edgware.SR2</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-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-feign</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>


</project>

启动类SpringCloudFeignApplication添加注解@EnableDiscoveryClient，@EnableFeignClients

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 SpringCloudFeignApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringCloudFeignApplication.class, args);
    }
}

application.properties

spring.application.name=spring-cloud-feign
server.port=8885
eureka.client.service-url.defaultZone=http://localhost:8761/eureka/
eureka.instance.prefer-ip-address=true
eureka.instance.instance-id=${spring.cloud.client.ipAddress}:${server.port}

新建一个HelloController.java

@RestController
public class HelloController {
    
    

    @Autowired
    IHelloService helloService;

    @RequestMapping(value = "hello", method = RequestMethod.GET)
    public String hello(@RequestParam String name) {
        return helloService.hello(name);
    }

}

IHelloService.java

@FeignClient(value = "SPRING-CLOUD-DEMO")
public interface IHelloService {

    @RequestMapping(value = "/hello", method = RequestMethod.POST)
    String hello(String name);

}

@FeignClient表示是远程调用的客户端，SPRING-CLOUD-DEMO是服务注册到eureka的实例名。

spring-cloud-demo工程地址：
https://github.com/perfiffer/micro-service/tree/master/spring-cloud-demo
spring-cloud-feign工程地址：
https://github.com/perfiffer/micro-service/tree/master/spring-cloud-feign
启动spring-cloud-feign工程和spring-cloud-demo工程，访问http://localhost:8885/hello?name=perfiffer，页面返回”Hello, perfiffer”。