Spring Cloud Netflix入门（Feign）

Feign是一个很好用的REST通讯包，十分强大。

1、MyFeignClient

package com.neohope.springcloud.test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import feign.hystrix.FallbackFactory;


import org.springframework.stereotype.Component;

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients(clients = {MyFeignClient.IServiceClient.class})
@RestController
public class MyFeignClient 
{
	@Value("${spring.application.name}")
	private String appName;
	
	@RequestMapping("/appName")
	public String appName() {
		return appName;
	}
	
	public static void main(String[] args)
	{
		new SpringApplicationBuilder(MyFeignClient.class).web(true).run(args);
	}
	
	@RequestMapping("/")
	public String hello() {
		return "It works";
	}
	
	@Autowired
	private IServiceClient aClient;
	
	@RequestMapping("/invokeC")
	public String invokeC() {
		return aClient.invokeA();
	}
	
	@RequestMapping("/invokeC/{clientName}")
    String invokeC(@PathVariable("clientName") String clientName)
    {
		if(aClient==null)
		{
			return "aClient is null";
		}
		else
		{
			//return aClient.invokeA(clientName);
			return aClient.invokeA();
		}
    }
	
	//primary = false
	@FeignClient(name="netflix-feign-server", configuration = MyFeignClientConfiguration.class, fallbackFactory=HystrixClientFallbackFactory.class)
	public interface IServiceClient {
	    @RequestMapping(method = RequestMethod.GET, value = "/invokeA")
	    String invokeA();

	    //@RequestMapping(method = RequestMethod.GET, value = "/invokeA/{clientName}", consumes = "application/json")
	    //String invokeA(@PathVariable("clientName") String clientName);
	}
	
	@Component
    public static class HystrixClientFallbackFactory implements FallbackFactory<IServiceClient>{
    	@Override
    	public IServiceClient create(final Throwable cause) {
    		return new IServiceClient() {
    			@Override
    		    public String invokeA()
    		    {
    				return "invokeA failed: "+cause.getMessage();
    		    }

    			//@Override
    			//public String invokeA(String clientName)
    		    //{
    			//	return "invokeA with clientName "+clientName+" failed: "+cause.getMessage();
    		    //}
    		};
    	}
    }
}

2、MyFeignClientConfiguration

package com.neohope.springcloud.test;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import feign.Logger;
import feign.auth.BasicAuthRequestInterceptor;

@Configuration
public class MyFeignClientConfiguration {
	@Bean
	public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
		return new BasicAuthRequestInterceptor("user", "hystrix");
	}

	/*
	@Bean
	Logger.Level feignLoggerLevel() {
		return Logger.Level.FULL;
	}
	*/
}

3、pom.xml

<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.cloud.stream.app</groupId>
		<artifactId>app-starters-build</artifactId>
		<version>1.1.3.M1</version>
	</parent>

	<groupId>com.neohope.springcloud.test</groupId>
	<artifactId>netflix-feign-client</artifactId>
	<version>1.0.0</version>
	<packaging>jar</packaging>

	<name>netflix-feign-client</name>
	<url>http://maven.apache.org</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>4.3.6.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>4.3.6.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>com.netflix.hystrix</groupId>
			<artifactId>hystrix-javanica</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-feign</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-hystrix</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-actuator</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-eureka</artifactId>
			<version>1.3.0.M1</version>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot</artifactId>
			<version>1.5.1.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-autoconfigure</artifactId>
			<version>1.5.1.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

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

4、application.properties

spring.application.name=feign-client
server.port=7002
security.user.name=user
security.user.password=hystrix
eureka.client.serviceUrl.defaultZone=http://user:hystrix@localhost:7000/eureka/
eureka.client.preferSameZoneEureka=true
eureka.client.healthcheck.enabled=true
eureka.instance.metadataMap.zone = zone1
eureka.instance.statusPageUrlPath=${management.context-path}/info
eureka.instance.healthCheckUrlPath=${management.context-path}/health
eureka.instance.lease-renewal-interval-in-seconds=5
eureka.instance.lease-expiration-duration-in-seconds=10
feign.hystrix.enabled=true
#feign.compression.request.enabled=true
#feign.compression.response.enabled=true
#feign.compression.request.enabled=true
#feign.compression.request.mime-types=text/xml,application/xml,application/json
#feign.compression.request.min-request-size=2048
#NONE,BASIC,HEADERS,FULL
logging.level.com.neohope.springcloud.test.MyFeignClient.IServiceClient=BASIC