SpringCloud学习笔记（14）----Spring Cloud Netflix之Hystrix对Feign的支持

1. Hystrix对Feign的支持

　　添加Feign中IUserBiz的实现类HystrixFallBack：

package com.wangx.cloud.springcloud02consumer.configure;

import com.wangx.cloud.springcloud02consumer.api.UserApi;
import org.springframework.stereotype.Component;

@Component
public class HystrixFallBack implements UserApi {
    @Override
    public String getUser(Integer id) {
        System.out.println("连接超时.....");
        return "system error";
    }


}

　　使用@component注解注册成组件。在@FeignClient注解里面添加fallback属性即可。

　　如下：

package com.wangx.cloud.springcloud02consumer.api;

import com.wangx.cloud.springcloud02consumer.configure.FooConfiguration;
import com.wangx.cloud.springcloud02consumer.configure.HystrixFallBack;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

@FeignClient(value = "spring-cloud-provider", configuration = FooConfiguration.class, fallback = HystrixFallBack.class)
public interface UserApi {

    @RequestMapping(value = "/user/getUser")
    String getUser(@RequestParam(value = "id") Integer id);

}

　　当出现请求错误或超时时，就会执行实现类中的方法。

　　熔断设置

　　

#默认为false，如果想用断路由，要打开这个设置
feign.hystrix.enabled=true

#断路器线程池超时时间,这个值一定要比ribbon超时时间长，毫秒
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=16000

　　单个应用禁用Hystrix

　　在FooConfiguration中配置一个bean

　　

package com.wangx.cloud.springcloud02consumer.configure;

import feign.Feign;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

@Configuration
public class FooConfiguration {
    @Bean
    @Scope("prototype")
    public Feign.Builder feignBuilder() {
        return Feign.builder();
    }
}

　　配置隔离级别

# 在feign和Ribbon里面配置隔离策略（全局配置）
#hystrix.command.default.execution.isolation.strategy=SEMAPHORE
# 配置单个 ystrixCommandKey在Ribbon下面默认为方法名，在feign下面默认为类名#方法名（参数类型）
#hystrix.command.HystrixCommandKey.execution.isolation.strategy=SEMAPHORE

　　说明：HystrixCommandKey在Ribbon下面默认为方法名，在feign下面默认为类名#方法名（参数类型）

　　Feign下的HystrixCommandKey类的配置

　　

package com.wangx.cloud.springcloud02consumer.configure;

import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommand.Setter;
import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixCommandKey;

import feign.Feign;
import feign.Target;
import feign.hystrix.HystrixFeign;
import feign.hystrix.SetterFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

import java.lang.reflect.Method;

@Configuration
public class FooConfiguration {
    @Bean
    @Scope("prototype")
    public Feign.Builder feignBuilder() {
        class RcSetterFactory implements SetterFactory {
            @Override
            public Setter create(Target<?> target, Method method) {
                String groupKey = target.name();
                String commandKey = method.getName();
                return HystrixCommand.Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey))
                        .andCommandKey(HystrixCommandKey.Factory.asKey(commandKey));
            }
        }
        return HystrixFeign.builder().setterFactory(new RcSetterFactory());
        //return Feign.builder();
    }
}