spring cloud之hystrix

 

 

 

1，hystrix降级（启动类上开启（@EnableHystrix）

     01-1在接口上添加注解
         @HystrixCommand(fallbackMethod ="payment_fail_handle",commandProperties = {
         @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "1500")
         })
     01-2 编写payment_fail_handle方法
         缺点：每个方法上都要加，代码冗余
    改进

    02-1 在类上添加@DefaultProperties(defaultFallback = "payment_default_fallBackMethod")
           在接口上添加@HystrixCommand
     02-2 编写payment_default_fallBackMethod方法

     在升级

  03-1在调用service上加上@FeignClient(value = "CLOUD-PAYMENT-HYSTRIX-SERVECE",fallback = PaymentHystrixFallBackService.class)

 

 

 03-2 编写PaymentHystrixFallBackService类实现service

 

 

 

2，hystrix熔断

        在启动类上添加 @EnableCircuitBreaker

         在需要熔断的方法上添加

@HystrixCommand(fallbackMethod = "paymentCircuitBreaker_fallBack", commandProperties = {
        @HystrixProperty(name = "circuitBreaker.enabled", value = "true"),//是否开启断路器
        @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "10"),//请求次数
        @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds", value = "10000"),//时间窗口期
        @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage", value = "60"),//失败率达到多少后跳闸
})
解释：在10000（10秒）内，10次请求失败率达到60%，即该接口熔断，返回paymentCircuitBreaker_fallBack方法返回结果

编写 paymentCircuitBreaker_fallBack方法，该方法为熔断调用的方法

 

 

3，hystrix 限流

 

4，hystrix图形化dashboard搭建

     新建moudle1模块（端口9001）

 

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
    <version>2.2.2.RELEASE</version>
</dependency>

在启动类上加@EnableHystrixDashboard

监测的模块

<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>

在启动类上添加@EnableCircuitBreaker
在启动类里注入

@Bean
public ServletRegistrationBean getServlet(){
    HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();
    ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet);
    registrationBean.setLoadOnStartup(1);
    registrationBean.addUrlMappings("/hystrix.stream");
    registrationBean.setName("HystrixMetricsStreamServlet");
    return registrationBean;
}

访问moudle1模块  http://localhost:9001/hystrix