Feign 集成 Hystrix实现不同的调用接口不同的设置方式

hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=3000

com.netflix.hystrix.HystrixCommandProperties

private static HystrixProperty<Boolean> getProperty(String propertyPrefix, HystrixCommandKey key, String instanceProperty, Boolean builderOverrideValue, Boolean defaultValue) {
        return forBoolean()
                .add(propertyPrefix + ".command." + key.name() + "." + instanceProperty, builderOverrideValue)
                .add(propertyPrefix + ".command.default." + instanceProperty, defaultValue)
                .build();
    }

@Override
  public Object invoke(final Object proxy, final Method method, final Object[] args)
      throws Throwable {
    .............
	 // setterMethodMap 封装 hystrixCommand 配置信息（超时时间、是否重试.....）
    HystrixCommand<Object> hystrixCommand = new HystrixCommand<Object>(setterMethodMap.get(method)) {
      @Override
      protected Object run() throws Exception {
        ....
        HystrixInvocationHandler.this.dispatch.get(method).invoke(args);
      	....
      }
      @Override
      protected Object getFallback() {
        .........
      }
    };
   ......
    return hystrixCommand.execute();
  }

final class HystrixInvocationHandler implements InvocationHandler {
  
  private final Target<?> target;
  private final Map<Method, MethodHandler> dispatch;
  private final FallbackFactory<?> fallbackFactory; // Nullable
  private final Map<Method, Method> fallbackMethodMap;
  private final Map<Method, Setter> setterMethodMap;
	HystrixInvocationHandler(Target<?> target, Map<Method, MethodHandler> dispatch,
                           SetterFactory setterFactory, FallbackFactory<?> fallbackFactory) {
    this.target = checkNotNull(target, "target");
    this.dispatch = checkNotNull(dispatch, "dispatch");
    this.fallbackFactory = fallbackFactory;
    this.fallbackMethodMap = toFallbackMethod(dispatch);
    this.setterMethodMap = toSetters(setterFactory, target, dispatch.keySet());
  }  
}

target:56, HystrixTargeter (org.springframework.cloud.openfeign)

// HystrixTargeter 这个类看代码就知道，对应这 @FeignClient 注解的接口
@SuppressWarnings("unchecked")
class HystrixTargeter implements Targeter {
	@Override
	public <T> T target(FeignClientFactoryBean factory, Feign.Builder feign, FeignContext context,
						Target.HardCodedTarget<T> target) {
		.....   
   
		feign.hystrix.HystrixFeign.Builder builder = (feign.hystrix.HystrixFeign.Builder) feign;
    // 这里其实是容器中拿到 SetterFactory 配置类
		SetterFactory setterFactory = getOptional(factory.getName(), context,
			SetterFactory.class);
		if (setterFactory != null) {
			builder.setterFactory(setterFactory);
		}
   
    // 从 @FeignClient 注解中读取或者默认
    
		Class<?> fallback = factory.getFallback();
		if (fallback != void.class) {
			return targetWithFallback(factory.getName(), context, target, builder, fallback);
		}
		Class<?> fallbackFactory = factory.getFallbackFactory();
		if (fallbackFactory != void.class) {
			return targetWithFallbackFactory(factory.getName(), context, target, builder, fallbackFactory);
		}
		return feign.target(target);
	}
	.....
	private <T> T getOptional(String feignClientName, FeignContext context,
		Class<T> beanType) {
		return context.getInstance(feignClientName, beanType);
	}
}

public interface SetterFactory {
  HystrixCommand.Setter create(Target<?> target, Method method);
	// 默认实现
  final class Default implements SetterFactory {
    @Override
    public HystrixCommand.Setter create(Target<?> target, Method method) {
      String groupKey = target.name();
      String commandKey = Feign.configKey(target.type(), method);
      // HystrixCommandKey、group 赋值
      return HystrixCommand.Setter
          .withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey))
          .andCommandKey(HystrixCommandKey.Factory.asKey(commandKey));
    }
  }
}

@FeignClient(value = "itemRobot", path = "cloud/device")
public interface Deviceapi {
    @RequestMapping(value = "/login", method = RequestMethod.GET)
    ServerResponse<String> login(@RequestParam String appId);
  
   @RequestMapping(value = "/loGout", method = RequestMethod.GET)
    ServerResponse<String> logout(@RequestParam String appId);
}

# login() 方法映射
hystrix.command.login.execution.isolation.thread.timeoutInMilliseconds=10000
# logout() 方法映射
hystrix.command.logout.execution.isolation.thread.timeoutInMilliseconds=10000

com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand

	@HystrixCommand(groupKey="accountPayGroup",commandKey="accountPay",threadPoolKey="account",threadPoolProperties= {
			@HystrixProperty(name="coreSize",value="20"),
			@HystrixProperty(name="maxQueueSize",value="50")
	},commandProperties={
			@HystrixProperty(name="circuitBreaker.sleepWindowInMilliseconds",value="3000"),
			@HystrixProperty(name="circuitBreaker.errorThresholdPercentage",value="40")
	})

@Target({TYPE, METHOD})
@Retention(RUNTIME)
public @interface CusHystrixCommandKey {
   // 对应 commandKey
    String name();
}

import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandGroupKey;
import com.netflix.hystrix.HystrixCommandKey;
import feign.Feign;
import feign.Target;
import feign.hystrix.SetterFactory;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import java.lang.reflect.Method;
@Component
public class MyHystrixFactory implements SetterFactory {
    @Override
    public HystrixCommand.Setter create(Target<?> target, Method method) {
        String groupKey = target.name();
        String commandKey = Feign.configKey(target.type(), method);
        CusHystrixCommandKey annotation = method.getAnnotation(CusHystrixCommandKey.class);
        if (annotation == null) {
						// 如果指定方法没有 CusHystrixCommandKey 注解，用 FeignClient.value() 作为key
            FeignClient feignClient = method.getDeclarinGClass().getAnnotation(FeignClient.class);
            commandKey = feignClient.value();
        } else {
          // 否则获取指定的name() 作为key
            commandKey = annotation.name();
        }
        return HystrixCommand.Setter
                .withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey))
                .andCommandKey(HystrixCommandKey.Factory.asKey(commandKey));
    }
}