springcloud Feign断路器实战和问题总结

断路由是防止该服务调用其他外服务时，外服务宕机或者出差时，影响到本服务的宕机，引起大面积的瘫痪，所以才有了断路由的由来。

springcloud Feign已经实现了Hystrix ,所以不用再引Hystrix的maven依赖

1. 搭建一个eureka注册中心和service参考下面的文章

springcloud项目实战

2. 创建项目如下

2.1 pom 文件

<?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.xue</groupId>
<artifactId>spring-curstomA</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>spring-curstomA</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> 
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>

<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</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>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RELEASE</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>

2.2 application.properties配置文件

#服务名称
spring.application.name=ribbon-consumer
#端口号
server.port=5555
#注册中心
eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka/
spring.cloud.config.discovery.enabled=true
#注册中心的服务id
spring.cloud.config.discovery.serviceId=compute-server
#打开对Hystrix断路由
feign.hystrix.enabled=true

2.3 启动类注解

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
public class SpringCurstomAApplication {
public static void main(String[] args) {
SpringApplication.run(SpringCurstomAApplication.class, args);
}
}

2.4 controller层

@RestController
public class MyController {
@Autowired
HelloService service;
@RequestMapping("/feign-customer")
public String testA() {
return service.hello();
}
}

2.5 feign 接口

//服务名和回调类
@FeignClient(value="COMPUTE-SERVICE1",fallback=HelloServiceFallback.class)
public interface HelloService {
@RequestMapping("/info") //对应具体服务中的接口地址（具体服务controller 层的暴露接口）可以指定具体的get/post
String hello();
}

2.6 feign 实现类

@Component//该注解不能少，否则报错
public class HelloServiceFallback implements HelloService {
@Override
public String hello() {
return "request error";
}
}

效果把要调用的服务停止后如下图

总结

如果项目还是报错，要检查三个地方

1. pom文件

<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RELEASE</version>//一定要是Dalston 不能是 Brixton
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>

2. application.properties

#打开对Hystrix断路由
feign.hystrix.enabled=true

3. 启动类注解

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients//该注解不能少
public class SpringCurstomAApplication {
public static void main(String[] args) {
SpringApplication.run(SpringCurstomAApplication.class, args);
}
}

springcloud Feign断路器实战和问题总结

springcloud Feign断路器实战和问题总结

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