Spring Cloud Ribbon 整合 Hystrix

在前面随笔 Spring Cloud 之 Ribbon 的ribbon工程基础上进行改造

1.pom.xml

加入依赖

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

即pom.xml为

<?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.dzpykj</groupId>
    <artifactId>ribbon</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>ribbon</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 /> <!-- lookup parent from repository -->
    </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>

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

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-hystrix</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
</project>

2.application.yml文件配置不变

spring:
  application:
    name: ribbon
server:
  port: 8765
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3.启动类加入@EnableCircuitBreaker注解开启Hystrix

package com.dzpykj;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker //@EnableCircuitBreaker注解表明使用断路器
public class RibbonApplication {

    @Autowired
    private RestTemplateBuilder builder;

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate() {
        return builder.build();
    }

//    @Bean
//    @LoadBalanced
//    RestTemplate restTemplate() {
//        return new RestTemplate();
//    }

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

4.新建HelloService类

重点是@HystrixCommand注解,fallbackMethod为异常时的回调方法

package com.dzpykj.hystrixService;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;

@Service
public class HelloService {

    @Value("${server.port}")
    String port;

    @Autowired
    RestTemplate restTemplate;

    @HystrixCommand(fallbackMethod = "helloErrorFallBack")
    public String hello(String name) {
        return restTemplate.getForObject("http://eurekaclient/hi?name="+name, String.class);
    }

    public String helloErrorFallBack(String name) {
        return "Sorry "+name+",when you are visting ribbon project,port:"+port+",you meet an error";
    }
}

5.改造HelloController,调用HelloService的hello方法

package com.dzpykj.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.dzpykj.hystrixService.HelloService;

@RestController
public class HelloController {

    @Autowired
    RestTemplate restTemplate;

    @Autowired
    HelloService helloService;

    @RequestMapping("/hello/{name}")
    public String hello(@PathVariable String name) {
        return restTemplate.getForObject("http://eurekaclient/hi?name="+name, String.class);
    }

    @RequestMapping("/hi/{name}")
    public String hi(@PathVariable String name) {
        return helloService.hello(name);
    }
}

6.准备工作完成,开始测试.依次启动Eureka服务集群、Eureka单个客户端、Ribbon工程

6.1 按照Spring Cloud Eureka Server集群Demo级搭建的步骤启动Eureka服务peer1,peer2集群

6.2按照Spring Cloud Eureka服务Demo级搭建启动8763的Eureka客户端

6.3启动Ribbon工程

7.访问 http://localhost:8765/hi/chaixy

8.模拟eurekaclient服务异常:手动将eurekaclient服务关闭,再次访问 http://localhost:8765/hi/chaixy

可以看到,当eurekaclient服务关闭时,访问遇到异常,回调了异常时的回调方法helloErrorFallBack方法(HelloService类内的方法)