12、Feign整合断路器Hystrix

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BUG弄潮儿 2019-08-03 20:38:52 博主文章分类：spring ©著作权

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上编说了《RestTemplate+Ribbon整合断路器Hystrix》，这篇来看看如何Feign整合断路器Hystrix，Feign整合断路器Hystrix也是相对比较简单的。Feign默认已经自带断路器Hystrix，所以不需要像RestTemplate+Ribbon整合断路器Hystrix那样需要在SpringBoot的启动类添加注解。但是Feign自带断路器并没有打开，需要做些额外的配置。

feign:
	 hystrix:
		 enabled: true

1、新建项目sc-eureka-client-consumer-feign-hystrix，对应的pom.xml文件如下

<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>spring-cloud</groupId>
	<artifactId>sc-eureka-client-consumer-feign</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>sc-eureka-client-consumer-feign</name>
	<url>http://maven.apache.org</url>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.4.RELEASE</version>
	</parent>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>Finchley.RELEASE</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>

		</dependencies>
	</dependencyManagement>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<maven.compiler.source>1.8</maven.compiler.source>
		<maven.compiler.target>1.8</maven.compiler.target>
	</properties>

	<dependencies>

		<!-- 说明是一个 eureka client -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<!-- <dependency> 
						<groupId>org.springframework.cloud</groupId> 
						<artifactId>spring-cloud-starter-feign</artifactId> 
					<version>1.4.5.RELEASE</version> 
			 </dependency> -->

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-openfeign</artifactId>
		</dependency>

	</dependencies>
</project>

备注：从继续关系可以看出spring-cloud-starter-openfeign已经集成断路器Hystrix 2、新建springboot启动类

package sc.consumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
public class ConsumerFeignApplication {

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

}

3、新建配置文件bootstrap.yml和application.yml bootstrap.yml

server:
	port: 5800

application.yml

spring:
	application:
		name: sc-eureka-client-consumer-feign-hystrix

eureka:
	client:
		registerWithEureka: true #是否将自己注册到Eureka服务中，默认为true
		fetchRegistry: true #是否从Eureka中获取注册信息，默认为true
		serviceUrl:
			defaultZone: http://localhost:5001/eureka/

feign:
	hystrix:
enabled: true

说明：在application.yml配置文件添加了开启断路器Hystrix的配置项

4、新建服务消费者类UserService.java

package sc.consumer.service;

import java.util.Map;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;

import sc.consumer.model.User;
import sc.consumer.service.hystrix.UserServiceHystrix;

@FeignClient(value="sc-eureka-client-provider", fallback=UserServiceHystrix.class)
public interface UserService {

	@GetMapping("/user/getUser/{id}")
	Map<String, Object> getUser(@PathVariable(value ="id") Long id);

	@RequestMapping("/user/listUser")
	Map<String, Object> listUser();

	@PostMapping("/user/addUser")
	Map<String, Object> addUser(@RequestBody User user);

	@PutMapping("/user/updateUser")
	Map<String, Object> updateUser(@RequestBody User user);

	@DeleteMapping("/user/deleteUser/{id}")
	Map<String, Object> deleteUser(@PathVariable(value ="id") Long id);

}

可以看到在该类的FeignClient注解上添加了一个属性fallback

5、新建断路器处理类UserServiceHystrix.java

package sc.consumer.service.hystrix;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.stereotype.Component;

import sc.consumer.model.User;
import sc.consumer.service.UserService;

@Component
public class UserServiceHystrix  implements UserService{

	@Override
	public Map<String, Object> getUser(Long id) {
		Map<String, Object> result = new HashMap<String, Object>();
		result.put("code", "000000");
		result.put("msg", "success");
		User u = new User();
		u.setId(-1L);
		u.setUserName("failBackName");
		result.put("body", u);
		return result;
	}

	@Override
	public Map<String, Object> listUser() {
		Map<String, Object> result = new HashMap<String, Object>();
		result.put("code", "000000");
		result.put("msg", "success");
		List<User> list = new ArrayList<User>();
		User u = new User();
		u.setId(-1L);
		u.setUserName("failBackName");
		list.add(u);
		result.put("body", list);
		return result;
	}

	@Override
	public Map<String, Object> addUser(User user) {
		Map<String, Object> result = new HashMap<String, Object>();
		result.put("code", "000000");
		result.put("msg", "success");
		result.put("body", 0);
		return result;
	}

	@Override
	public Map<String, Object> updateUser(User user) {
		Map<String, Object> result = new HashMap<String, Object>();
		result.put("code", "000000");
		result.put("msg", "success");
		result.put("body", 0);
		return result;
	}

	@Override
	public Map<String, Object> deleteUser(Long id) {
		Map<String, Object> result = new HashMap<String, Object>();
		result.put("code", "000000");
		result.put("msg", "success");
		result.put("body", 0);
		return result;
	}

}

该类实现了UserService接口，并实现了该接口的所有方法。

6、分别启动注册中心sc-eureka-server和服务提供者sc-eureka-client-provider

7、启动sc-eureka-client-consumer-feign-hystrix，并验证是否启动成功方式一：查看日志看看对应的端口是启动
方式二：查看注册中心是否注册成功 8、使用postman验证断路器是否启用上篇从服务提供者是否正常启动验证断路器是否启动，今天看看从数据库是否启动来验证断路器是否启动（1）MySQL服务正常启动时访问： http://127.0.0.1:5800/feign/user/listUser