Spring Cloud Feign fallback打印出真實的錯誤信息

https://www.cnblogs.com/qq931399960/p/15846408.html

根據上述操作，雖然發生錯誤后，可以執行fallback，但具體的錯誤信息后端沒有打印，具體的錯誤信息有時候很重要，可以幫助我們來定位錯誤的根本原因

根據Spring Cloud OpenFeign官方文檔"1.6. Feign Spring Cloud CircuitBreaker Fallbacks"，實現該功能也很簡單

在本例中，將之前使用的feignclient注解的屬性fallback改為使用fallbackFactory，並且callback實現類改為ConsumerServiceCallbackFactory

feign接口

package com.demo.service;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

import com.demo.entity.ResultEntity;
import com.demo.service.callback.ConsumerServiceCallbackFactory;

@FeignClient(name = "SERVICE-PROVIDER", fallbackFactory = ConsumerServiceCallbackFactory.class)
public interface ConsumerService {

    /**
     * 此處不能返回Object，要么返回String，要么返回存在get set方法的實體對象或者map
     * @param id
     * @return
     */
    @RequestMapping("/getData/{id}")
    ResultEntity getData(@PathVariable String id);
} 

fallback factory

package com.demo.service.callback;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.openfeign.FallbackFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.PathVariable;

import com.demo.entity.ResultEntity;
import com.demo.service.ConsumerService;

@Component
public class ConsumerServiceCallbackFactory implements FallbackFactory<ConsumerServiceCallBack>{

    private Logger logger = LoggerFactory.getLogger(ConsumerServiceCallbackFactory.class);
    @Override
    public ConsumerServiceCallBack create(Throwable e) {
        logger.error("",e);
        return new ConsumerServiceCallBack();
    }

}
class ConsumerServiceCallBack implements ConsumerService{

    private Logger logger = LoggerFactory.getLogger(ConsumerServiceCallBack.class);
    
    @Override
    public ResultEntity getData(@PathVariable String id) {
        logger.error("call back id: {}", id);
        return new ResultEntity(false, "error");
    }
}

測試

將服務提供者服務線程休眠一段時間，模擬出read timeout，重啟服務提供者合並服務消費者，再次訪問：http://127.0.0.1:8081/getData/10

瀏覽器顯示

 

后端打印出異常信息

2022-01-26 15:05:48.239 ERROR 193180 --- [nio-8081-exec-4] c.d.s.c.ConsumerServiceCallbackFactory   : 

java.util.concurrent.TimeoutException: TimeLimiter 'ConsumerService#getData(String)' recorded a timeout exception.
	at java.util.concurrent.FutureTask.get(Unknown Source) ~[na:1.8.0_172]
	at io.github.resilience4j.timelimiter.internal.TimeLimiterImpl.lambda$decorateFutureSupplier$0(TimeLimiterImpl.java:46) ~[resilience4j-timelimiter-1.7.0.jar:1.7.0]
	at io.github.resilience4j.circuitbreaker.CircuitBreaker.lambda$decorateCallable$3(CircuitBreaker.java:171) ~[resilience4j-circuitbreaker-1.7.0.jar:1.7.0]
	at io.vavr.control.Try.of(Try.java:75) ~[vavr-0.10.2.jar:na]

從異常信息可以看出發生了超時