Spring Cloud入门系列（十）- 服务熔断与降级之Hystrix（已停更，建议切换到Sentinel）

模块构建

新建 客户端 模块：cloud-consumer-feign-hystrix-order80

结构图，如下：

pom.xml

<?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">
    <parent>
        <artifactId>cloud201230</artifactId>
        <groupId>com.banana</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-consumer-feign-hystrix-order80</artifactId>

    <dependencies>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--hystrix-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
        <!--eureka  client-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!--引入自定义的api通用包，可以使用Payment支付Entity-->
        <dependency>
            <groupId>com.banana</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>
</project>

application.yml

server:
  port: 80

eureka:
  client:
    #是否将自己注册到注册中心, 默认true
    register-with-eureka: false
    #是否从EurekaServer抓取已有的注册信息,单机无所谓,集群必须设置为true配合ribbon使用负载均衡
    #fetch-registry: true
    service-url:
      defaultZone: http://localhost:7001/eureka  #单机版

feign:
  hystrix:
    enabled: true

FeignHystrixOrder80

package com.banana.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.cloud.openfeign.EnableFeignClients;

/**
 * @author layman
 * @date 2021/1/18
 */
@SpringBootApplication
@EnableFeignClients
@EnableHystrix
public class FeignHystrixOrder80 {
    public static void main(String[] args) {
            SpringApplication.run(FeignHystrixOrder80.class,args);
        }
}

OpenFeignOrderService

package com.banana.springcloud.service;

import com.banana.springcloud.service.fallback.OpenFeignOrderFallbackService;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

/**
 * FeignClient注解中的value属性指定了要调用的{服务}名
 * @author layman
 * @date 2021/1/18
 * fallback为value指定的服务名，提供统一的服务降级处理类OpenFeignOrderFallbackService。
 *      如果正常访问，不会走fallback指定的OpenFeignOrderFallbackService类，而是直接访问。
 *      如果异常访问，需要服务降级，才会走fallback指定的OpenFeignOrderFallbackService。
 *          A:如果是feignSuccess方法出现异常，那么就会去OpenFeignOrderFallbackService.class找对应的feignSuccess方法，处理fallback
 */
@Component
@FeignClient(value = "CLOUD-PROVIDER-HYSTRIX-PAYMENT",fallback = OpenFeignOrderFallbackService.class)
public interface OpenFeignOrderService {

    /**
     * 模拟成功访问
     * @param id：主键
     * @return CommonResult<Payment>
     */
    @GetMapping(value = "/payment/hystrix/success/{id}")
    String feignSuccess(@PathVariable("id") Long id);
    /**
     * 模拟openFeign访问超时
     * @param id：主键
     * @return String
     */
    @GetMapping("/payment/hystrix/timeout/{id}")
    String feignTimeout(@PathVariable("id") Long id);
}

OpenFeignOrderFallbackService

package com.banana.springcloud.service.fallback;

import com.banana.springcloud.service.OpenFeignOrderService;
import org.springframework.stereotype.Component;

/**
 * 全局服务降级处理类
 * @author layman
 * @date 2021/1/18
 */
@Component
public class OpenFeignOrderFallbackService implements OpenFeignOrderService {
    /**
     * 模拟成功访问
     * @param id ：主键
     * @return CommonResult<Payment>
     */
    @Override
    public String feignSuccess(Long id) {
        return "-------OpenFeignOrderFallbackService, feignSuccess出错啦 , o(╥﹏╥)o";
    }
    /**
     * 模拟openFeign访问超时
     * @param id ：主键
     * @return String
     */
    @Override
    public String feignTimeout(Long id) {
        return "-------OpenFeignOrderFallbackService, feignTimeout出错啦 , o(╥﹏╥)o";
    }
}

OpenFeignOrderController

package com.banana.springcloud.controller;

import com.banana.springcloud.service.OpenFeignOrderService;
import com.netflix.hystrix.contrib.javanica.annotation.DefaultProperties;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/**
 * @author layman
 * @date 2021/1/18
 */
@RestController
@RequestMapping("/consumer/hyxtrix")
@DefaultProperties(defaultFallback = "payment_Global_FallbackMethod")
public class OpenFeignOrderController {

    @Resource
    private OpenFeignOrderService openFeignOrderService;

    @GetMapping("/success/{id}")
    public String feignSuccess(@PathVariable("id") Long id){
        return openFeignOrderService.feignSuccess(id);
    }

    @GetMapping("/timeout/{id}")
    @HystrixCommand(fallbackMethod = "feignTimeoutHandler", commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "1000")
    })
    public String feignTimeout(@PathVariable("id") Long id){
        return openFeignOrderService.feignTimeout(id);
    }

    public String feignTimeoutHandler(@PathVariable("id") Long id){
        return "对方支付系统繁忙，请稍后重试！";
    }

    /**
    * HystrixCommand注解没有配置属性，走全局fallback方法
    */
    @GetMapping("/global/fallback")
    @HystrixCommand
    public String feignGlobalFallback(){
        String result = null;
        return result.toString();
    }
    /**
     * 全局fallback 降级方法
     */
    public String payment_Global_FallbackMethod() {
        return "Global异常处理信息，请稍后再试，o(╥﹏╥)o";
    }
}