SpringCloud（六） Hystrix入门

前提

• 一个可用的Eureka注册中心（文中以之前博客中双节点注册中心，不重要）
• 一个连接到这个注册中心的服务提供者

快速入门

项目搭建

搭建一个新maven项目，artifactid为Ribbon-consum-hystrix，依赖是在ribbon-customer项目上加入hystrix依赖，这里直接给出，pom.xml配置如下：

<?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.cnblogs.hellxz</groupId>
<artifactId>Ribbon-consum-hystrix</artifactId>
<version>1.0-SNAPSHOT</version>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/>
</parent>

<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>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
<version>RELEASE</version>
</dependency>
<!--暴露各种指标-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

<!--hystrix熔断器-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix</artifactId>
<version>RELEASE</version>
</dependency>
</dependencies>

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

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>

新建包com.cnblogs.hellxz,新建应用入口类RibbonApplication:

package com.cnblogs.hellxz;

import org.springframework.boot.SpringApplication;
import org.springframework.cloud.client.SpringCloudApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

/**
* @Author : Hellxz
* @Description: Hystrix熔断器使用HelloWorld
* @Date : 2018/4/20 10:03
*/
@SpringCloudApplication
public class RibbonApplication {

@Bean
@LoadBalanced
RestTemplate getRestTemplate(){
return new RestTemplate();
}

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

resources目录下添加配置文件application.yml，其中defaultZone的url为实际注册中心defaultZone地址

server:
port: 8088

spring:
application:
name: ribbon-hystrix

eureka:
client:
serviceUrl:
defaultZone: http://peer1:1111/eureka/,http://peer2:1112/eureka/

在com.cnblogs.hellxz包下分别新建controller包和service包，controller包中新建RibbonController，代码如下：

package com.cnblogs.hellxz.controller;

import com.cnblogs.hellxz.servcie.RibbonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
* @Author : Hellxz
* @Description: Ribbon消费者controller
* @Date : 2018/4/20 10:07
*/
@RestController
public class RibbonController {

@Autowired
RibbonService service;

@GetMapping("/hystrix/test")
public String helloHystrix(){
//调用服务层方法
return service.helloService();
}

}

service包下新建RibbonService，代码如下：

package com.cnblogs.hellxz.servcie;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

/**
* @Author : Hellxz
* @Description: Ribbon服务层
* @Date : 2018/4/20 10:08
*/
@Service
public class RibbonService {

@Autowired
private RestTemplate restTemplate;

@HystrixCommand(fallbackMethod = "hystrixFallback")
public String helloService(){
//调用服务提供者接口，正常则返回hello字符串
return restTemplate.getForEntity("http://hello-service/hello", String.class).getBody();
}

/**
* 调用服务失败处理方法
* @return “error"
*/
public String hystrixFallback(){
return "error";
}
}

项目最后的结构如图

测试

分别启动

注册中心

--->

服务提供者

--->

刚新建的项目

访问http://localhost:8088/hystrix/test
因为现在服务是正常的，返回了

hello

，如图

此时关闭服务提供者项目，再次访问，返回了

error

，如图