springcloud Feign断路器实战和问题总结

ゞ浴缸里的玫瑰 2022-05-30 07:07 157阅读 0赞

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][springcloud]

#### 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 ####

![20180307151542477][]

#### 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]: http://blog.csdn.net/u010938610/article/details/79282624
[20180307151542477]: /images/20220530/aed8784bf02e4c378e9cdaf3c8c2a2c9.png