Spring Cloud(Dalston.SR5)--Feign 与 Hystrix 断路器整合

  • 创建项目

    要使 Feign 与 Hystrix 进行整合,我们需要增加 Feign 和 Hystrix 的依赖,修改 POM.xml 中增加以下依赖项如下:

    <?xmlversion="1.0"encoding="UTF-8"?>

    <projectxmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

     
     

    <groupId>org.lixue</groupId>

    <artifactId>spring-cloud-hystrix-client</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

     
     

    <name>spring-cloud-hystrix-client</name>

    <description>DemoprojectforSpringBoot</description>

     
     

    <parent>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-parent</artifactId>

    <version>1.5.4.RELEASE</version>

    <relativePath/><!--lookupparentfromrepository-->

    </parent>

     
     

    <properties>

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

    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>

    <java.version>1.8</java.version>

    <spring-cloud.version>Dalston.SR5</spring-cloud.version>

    </properties>

     
     

    <dependencies>

    <dependency>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-web</artifactId>

    </dependency>

    <dependency>

    <groupId>org.springframework.cloud</groupId>

    <artifactId>spring-cloud-starter-eureka</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-ribbon</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-test</artifactId>

    <scope>test</scope>

    </dependency>

    </dependencies>

     
     

    <dependencyManagement>

    <dependencies>

    <dependency>

    <groupId>org.springframework.cloud</groupId>

    <artifactId>spring-cloud-dependencies</artifactId>

    <version>${spring-cloud.version}</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>

 
 

  • 增加配置

    还需要在 src/main/resources/application.yml 中,开启 Feign 的配置,如下:

    #配置应用名称

    spring:

    application:

    name:spring-cloud-hystrix-client

    #服务端口

    server:

    #启用feign的hystrix支持

    feign:

    hystrix:

    enabled:true

    #设置eureka服务注册中心的地址,如果多个以逗号分割

    eureka:

    client:

    service-url:

    defaultZone:http://eurekaserver01:9000/eureka/,http://eurekaserver02:9000/eureka/

     
     

  • 创建 Feign 客户端

    创建 Feign 客户端接口,增加回退的类实现,在 @FeignClient 注解中,设置 fallback 属性,如下:

    package org.lixue;

     
     

    import org.springframework.cloud.netflix.feign.FeignClient;

    import org.springframework.stereotype.Component;

    import org.springframework.web.bind.annotation.RequestMapping;

    import org.springframework.web.bind.annotation.RequestMethod;

    import org.springframework.web.bind.annotation.RequestParam;

     
     

    @FeignClient(name="HELLOWORLD-PROVIDER",fallback=HelloWorldFeignClient.HelloWorldFallback.class)

    public interface HelloWorldFeignClient{

     
     

    @RequestMapping(path="/speaks",method=RequestMethod.GET)

    String speak(@RequestParam(name="names")Stringname);

     
     

    @Component

    class HelloWorldFallback implements HelloWorldFeignClient{

     
     

    @Override

    public String speak(String name){

    return"speakfallbackisname="+name;

    }

    }

    }

 
 

  • 创建调用类

    只需要使用 @Autowired 注解标注 HelloWorldFeignClient 实例进行自动注入,然后调用 HelloWorldFeignClient 实例的方法即完成调用,如下:

    package org.lixue;

     
     

    import org.springframework.beans.factory.annotation.Autowired;

    import org.springframework.web.bind.annotation.RequestMapping;

    import org.springframework.web.bind.annotation.RequestMethod;

    import org.springframework.web.bind.annotation.RequestParam;

    import org.springframework.web.bind.annotation.RestController;

     
     

    import java.util.List;

    import java.util.Map;

    import java.util.concurrent.ExecutionException;

    import java.util.concurrent.Future;

     
     

    @RestController

    public class InvokerController{

     
     

    @Autowired

    private HelloWorldFeignClient helloWorldFeignClient;

     
     

    @RequestMapping(method=RequestMethod.GET,path="/speakFeign")

    public String speakFeign(@RequestParam("name")String name){

    return helloWorldFeignClient.speak(name);

    }

    }

 
 

 
 

  • 启动类

    增加 @EnableCircuitBreaker 和 @EnableFeignClients 注解,启用 Feign 和 Hystrix 功能,如下:

    package org.lixue;

     
     

    import org.springframework.boot.SpringApplication;

    import org.springframework.boot.autoconfigure.SpringBootApplication;

    import org.springframework.boot.web.servlet.ServletComponentScan;

    import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;

    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

    import org.springframework.cloud.netflix.feign.EnableFeignClients;

     
     

    @SpringBootApplication

    @EnableDiscoveryClient

    @EnableCircuitBreaker

    @EnableFeignClients

    @ServletComponentScan

    public class SpringCloudHystrixClientApplication{

     
     

    public static void main(String[]args){

    SpringApplication.run(SpringCloudHystrixClientApplication.class,args);

    }

    }

     
     

  • 测试验证

    由于我们使用了 Ribbon 因此首先启动 eureka-server 和 service-provider 服务,然后启动该项目,访问 http://localhost:8077/speak?name=abc 可以看到能正常返回信息,如下:

    Hello World abc Port=8080

    此时,关闭 service-provider 服务,然后在访问地址 http://localhost:8077/speak?name=abc 可以看到,由于服务已经不可用,因此执行了该方法的回退返回,返回如下:

    speak fallback is name=abc

     
     

  • 配置说明

    Feign 与 Hystrix 整合使用时,会自动帮我们生成 CommandKey,格式为:Feign 客户端接口名称#方法名() ,生成的 GroupKey 为 @FeignClient 注解的 name 属性,例如,上面示例生成的 CommandKey 为 HelloWorldFeignClient#speak() ,Groupkey 为 HELLOWORLD-PROVIDER,如果需要针对该 Feign 客户端设置 Hystrix 的配置属性,在 application.yml 中增加配置如下:

    #设置Hystrix的属性

    hystrix:

    command:

    HelloWorldFeignClient#speak():

    execution:

    isolation:

    thread:

    如果需要设置默认全局属性,则修改 application.yml 配置如下:

    #设置Hystrix的属性

    hystrix:

    command:

    default:

    execution:

    isolation:

    thread:

     
     

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