通过全局异常处理返回openfeign接口调用结果

没有添加全局异常处理时，当Controller的方法直接抛出异常时，openfeign会收到500错误，导致无法进行正常的处理。通过定义全局异常处理，将异常情况，通过预定义的错误码进行返回，以便调用端能够正常处理。

1. 定义全局异常类

package com.demo.handler;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;


@ControllerAdvice
public class GlobalExceptionHandler {
    private static Logger logger = LoggerFactory.getLogger(GlobalExceptionHandler.class);


    @ExceptionHandler(RuntimeException.class)
    @ResponseBody
    public AjaxResult handleException(Exception e, HttpServletRequest request) {
        logger.warn("请求url:[{}]出错", request.getRequestURL(), e);
        return AjaxResult.error(e.getMessage());
    }

//    @ExceptionHandler(BusinessException.class)
//    @ResponseBody
//    public Result handleException(BusinessException e, HttpServletRequest request) {
//        logger.warn("请求url:[{}]出错", request.getRequestURL(), e);
//        return ResultUtils.error(e.getCode(),e.getMessage());
//    }
}

2. 添加该类后，如果@ControllerAdvice不生效，需要确保能够扫描到，也就是需要放在启动类所在包之下。或者添加扫描路径，比如：

@SpringBootApplication(scanbasePackages = {"com.xxx"})