SpringCloud(Hoxton)--Hystrix服务降级（注解）-白红宇

SpringCloud(Hoxton)--Hystrix服务降级（注解）

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发布时间：2019-05-10

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cloud-provider-hystrix-payment8001模拟支付模块

依赖：


   
       
            
     
      cloud2020
             
     
      pers.zhang.springcloud
             
     
      1.0-SNAPSHOT
         
        
    
     4.0.0
        
    
     cloud-provider-hystrix-payment8001
        
            
             
                 
      
       org.springframework.cloud
                  
      
       spring-cloud-starter-netflix-hystrix
              
             
             
                 
      
       org.springframework.cloud
                  
      
       spring-cloud-starter-netflix-eureka-client
              
             
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-web
              
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-actuator
              
             
     
                  
      
       pers.zhang.springcloud
                  
      
       cloud-api-commons
                  
      
       ${project.version}
              
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-devtools
                  
      
       runtime
                  
      
       true
              
             
                 
      
       org.projectlombok
                  
      
       lombok
                  
      
       true
              
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-test
                  
      
       test

配置：application.yml

server:  port: 8001spring:  application:    name: cloud-provider-hystrix-paymenteureka:  client:    register-with-eureka: true    fetch-registry: true    service-url:      defaultZone: http://eureka7001.com:7001/eureka      #defaultZone: http://eureka7001.com:7001/eureka,http://wureka7002.com:7002/eureka

Service：

@Servicepublic class PaymentService {
       /**     * 正常访问，肯定OK     * @param id     * @return     */    public String paymentInfo_OK(Integer id) {
           return "线程池：" + Thread.currentThread().getName() + " paymentInfo_OK, id:" + id;    }    /**     * 超时错误     * @param id     * @return     */    @HystrixCommand(fallbackMethod = "paymentInfo_TimeOutHandler", commandProperties = {
               @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "2000")    })//指定超时回调,时间为2秒    public String paymentInfo_TimeOut(Integer id) {
           //int a = 10 / 0;        try {
   //睡3秒，模拟超时            TimeUnit.SECONDS.sleep(3);        } catch (InterruptedException e) {
               e.printStackTrace();        }        return "线程池：" + Thread.currentThread().getName() + " paymentInfo_TimeOut, id:" + id;    }    public String paymentInfo_TimeOutHandler(Integer id) {
           return "线程池：" + Thread.currentThread().getName() + " 系统繁忙，请稍后再试, id:" + id + "超时回调";    }}

Controller:

@RestController@Slf4jpublic class PaymentController {
       @Resource    PaymentService paymentService;    @Value("${server.port}")    String serverPort;    @GetMapping("/payment/hystrix/ok/{id}")    public String paymentInfo_OK(@PathVariable("id") Integer id) {
           String result = paymentService.paymentInfo_OK(id);        log.info("*****result:" + result);        return result;    }    @GetMapping("/payment/hystrix/timeout/{id}")    public String paymentInfo_TimeOut(@PathVariable("id") Integer id) {
           String result = paymentService.paymentInfo_TimeOut(id);        log.info("*****result:" + result);        return result;    }}

启动类：

@SpringBootApplication@EnableEurekaClient@EnableCircuitBreaker//开启public class PaymentHystrixMain8001 {
       public static void main(String[] args) {
           SpringApplication.run(PaymentHystrixMain8001.class, args);    }}

cloud-consumer-feign-hystrix-order80模拟订单模块

依赖：


   
       
            
     
      cloud2020
             
     
      pers.zhang.springcloud
             
     
      1.0-SNAPSHOT
         
        
    
     4.0.0
        
    
     cloud-consumer-feign-hystrix-order80
        
            
             
                 
      
       org.springframework.cloud
                  
      
       spring-cloud-starter-openfeign
              
             
             
                 
      
       org.springframework.cloud
                  
      
       spring-cloud-starter-netflix-hystrix
              
             
             
                 
      
       org.springframework.cloud
                  
      
       spring-cloud-starter-netflix-eureka-client
              
             
             
                 
      
       pers.zhang.springcloud
                  
      
       cloud-api-commons
                  
      
       ${project.version}
              
             
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-web
              
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-actuator
              
             
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-devtools
                  
      
       runtime
                  
      
       true
              
             
                 
      
       org.projectlombok
                  
      
       lombok
                  
      
       true
              
             
                 
      
       org.springframework.boot
                  
      
       spring-boot-starter-test
                  
      
       test

配置：application.yml

server:  port: 80eureka:  client:    register-with-eureka: false    service-url:      defaultZone: http://eureka7001.com:7001/eureka/feign:  hystrix:    enabled: true #开启hystrix

Service:

@Component@FeignClient(value = "CLOUD-PROVIDER-HYSTRIX-PAYMENT")//指定调用的服务名public interface PaymentHystrixService {
       @GetMapping("/payment/hystrix/ok/{id}")    public String paymentInfo_OK(@PathVariable("id") Integer id);    @GetMapping("/payment/hystrix/timeout/{id}")    public String paymentInfo_TimeOut(@PathVariable("id") Integer id);}

Controller:

@RestController@Slf4jpublic class OrderHystrixController {
       @Resource    PaymentHystrixService paymentHystrixService;    @GetMapping("/consumer/payment/hystrix/ok/{id}")    public String paymentInfo_OK(@PathVariable("id") Integer id) {
           String result = paymentHystrixService.paymentInfo_OK(id);        return result;    }    @GetMapping("/consumer/payment/hystrix/timeout/{id}")    @HystrixCommand(fallbackMethod = "paymentTimeOutFallbackMethod", commandProperties = {
               @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "1500")//超时1.5秒    })    public String paymentInfo_TimeOut(@PathVariable("id") Integer id) {
           String result = paymentHystrixService.paymentInfo_TimeOut(id);        return result;    }    public String paymentTimeOutFallbackMethod(@PathVariable("id") Integer id) {
           return "我是消费者80，对方支付系统繁忙，请10秒后再试或者自己运行出错请检查自己。";    }}

启动类：

@SpringBootApplication@EnableFeignClients@EnableHystrix//开启Hystrixpublic class OrderHystrixMain80 {
       public static void main(String[] args) {
           SpringApplication.run(OrderHystrixMain80.class, args);    }}

测试

我们在服务的提供方和消费方都使用了Hystrix，但是多数情况下只在消费方配置Hystrix。

启动Eureka，在启动支付和订单微服务。

先在8001端口进行本地测试：

访问：localhost:8001/payment/hystrix/ok/35，成功

访问：localhost:8001/payment/hystrix/timeout/33,失败，程序中睡眠3秒，触发Hystrix设置的2秒时限，服务降级，调用fallback方法：

通过80端口使用Feign调用8001：

访问：localhost/consumer/payment/hystrix/ok/22：成功：

访问：localhost/consumer/payment/hystrix/timeout/11：失败，订单模块作为消费方做出的超时限制为1.5秒，等待1.5秒无返回立即触发服务降级，调用fallback方法。

@DefaultProperties

每个方法都有一个fallback方法，为了避免代码膨胀，应该有一个同一的方法和自定义的fallback方法分开。

可以在类上加@Defaultproperties注解指定一个通用的fallback方法，凡是标注了@HystrixCommand但没有指定@HystrixProperty的方法，均使用@DefaultProperties指定的fallback方法。

修改80端口的Controller：

@RestController@Slf4j@DefaultProperties(defaultFallback = "payment_Global_FallbackMethod")public class OrderHystrixController {
       @Resource    PaymentHystrixService paymentHystrixService;    @GetMapping("/consumer/payment/hystrix/ok/{id}")    public String paymentInfo_OK(@PathVariable("id") Integer id) {
           String result = paymentHystrixService.paymentInfo_OK(id);        return result;    }    @GetMapping("/consumer/payment/hystrix/timeout/{id}")    //未指定fallback，使用@DefaultProperties指定的payment_Global_FallbackMethod    @HystrixCommand    // @HystrixCommand(fallbackMethod = "paymentTimeOutFallbackMethod", commandProperties = {
       //         @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "1500")//超时1.5秒    // })    public String paymentInfo_TimeOut(@PathVariable("id") Integer id) {
           int a = 10 / 0;        String result = paymentHystrixService.paymentInfo_TimeOut(id);        return result;    }    public String paymentTimeOutFallbackMethod(@PathVariable("id") Integer id) {
           return "我是消费者80，对方支付系统繁忙，请10秒后再试或者自己运行出错请检查自己。";    }        //默认fallback    public String payment_Global_FallbackMethod() {
           return "Global异常处理信息，请稍后再试...";    }}

重启，访问：localhost/consumer/payment/hystrix/timeout/33，失败，跳转到全局fallback：

fallback解耦

目前业务逻辑和fallback都混在一起，应该将两者分开。

只需要为Feign客户端定义的接口添加一个服务降级处理的实现类即可实现解耦。

新建类PaymentFallbackService，实现PaymentHystrixService接口：

@Componentpublic class PaymentFallbackService implements PaymentHystrixService {
       @Override    public String paymentInfo_OK(Integer id) {
           return "-------PaymentFallbackService paymentInfo_OK fall back--------";    }    @Override    public String paymentInfo_TimeOut(Integer id) {
           return "-------PaymentFallbackService paymentInfo_TimeOut fall back--------";    }}

在@FeignClient中指明fallback处理类：