SpringCloud之Hystrix

在微服务架构中,微服务之间互相依赖较大,相互之间调用必不可免的会失败。但当下游服务A因为瞬时流量导致服务崩溃,其他依赖于A服务的B、C服务由于调用A服务超时耗费了大量的资源,长时间下去,B、C服务也会崩溃。Hystrix就是用来解决服务之间相互调用失败,避免产生蝴蝶效应的熔断器,以及提供降级选项。Hystrix通过隔离服务之间的访问点,阻止它们之间的级联故障以及提供默认选项来实现这一目标,以提高系统的整体健壮性。

它主要解决什么问题?

用来避免由于服务之间依赖较重,出现个别服务宕机、停止服务导致大面积服务雪崩的情况。

一、Maven依赖

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<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

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

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

</dependencies>

二、启动类配置

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package com.springcloud.blog;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@EnableCircuitBreaker
@EnableFeignClients
public class BlogRibbonClientApplication {

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

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

三、修改配置文件(application.yml)

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eureka:
client:
fetchRegistry: true
serviceUrl:
defaultZone: http://localhost:8761/eureka/
ribbon:
okhttp:
enabled: true #
NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule # 默认为;轮询,这里改为随机
ConnectTimeout: 5000 # 连接超时时间(ms)
ReadTimeout: 5000 # 通信超时时间(ms)
hystrix:
enabled: true
command:
default:
execution:
isolation:
thread:
timeoutInMilliseconds: 6000 #
server:
port: 8765
spring:
application:
name: blog-ribbon-client

四、测试类

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package com.springcloud.blog.example;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;

@FeignClient(value="blog-api")
public interface FeignTestService {

@GetMapping("/juhe/getIpInfo")
String getIpInfo(@RequestParam String ip);


}

五、测试效果

也可以自定义fallback实现返回值,只不过我觉得默认的看起来效果比较好,就直接默认的。

文章目录
  1. 1. 一、Maven依赖
  2. 2. 二、启动类配置
  3. 3. 三、修改配置文件(application.yml)
  4. 4. 四、测试类
  5. 5. 五、测试效果