12、Feign整合断路器Hystrix

2024-12-05 技术教程

公众号： java乐园

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>  <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-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@EnableFeignClientspublic 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: 5800application.ymlspring: application: name: sc-eureka-client-consumer-feign-hystrixeureka: 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;@Componentpublic 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

（2）MySQL服务关闭时访问
http://127.0.0.1:5800/feign/user/listUser

再看下后台日志：

其他接口可以自行按照以上方式进行验证，看看断路器是否启动

源码 https://gitee.com/hjj520/spring-cloud-2.x