Feign全局异常处理

因项目重构采用spring cloud，feign不可避免。目前spring cloud在国内还不是很成熟，所以踩坑是免不了的。最近处理全局异常的问题，搜了个遍也没找到合适的解决方案。最后自己采取了一个不是perfect的方案处理了。终究问题还是解决了。

首先系统定义了两个异常类：

@Data
public class BusinessException extends RuntimeException{

   private Integer code;
    private String message;
    public BusinessException() {
    }
    public BusinessException(String errmsg) {
        super(errmsg);
        this.code=2;
        this.message=errmsg;
}
    public BusinessException(ExceptionEnum exceptionEnum) {
        super(exceptionEnum.getMsg());
        this.code=exceptionEnum.getCode();
        this.message=exceptionEnum.getMsg();
    }

    public BusinessException(int code ,String errmsg) {
        super(errmsg);
        this.code=code;
        this.message=errmsg;
    }


    @Override
    public String toString() {
        return "{" +
                "\"code\":" + code +
                ", \"message\":\"" + message + "\"" +"}";
    }
}

内部异常类如下：

public class InternalException extends RuntimeException{

    public InternalException(String msg) {
        super(msg);

    }

}

采用@controllerAdvice全局捕获异常

/**
 * 全局异常处理类
 */
@Slf4j
@ControllerAdvice(basePackages = {"捕获哪些包"})
public class ExceptionHandle {

    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    public ResultResponse handle(Exception e) {
        if (e instanceof BusinessException) {
            BusinessException businessException = (BusinessException) e;
            if(businessException.getCode()==null){
                return ResultResponse.error(businessException.getMessage());
            }
            return ResultResponse.error(businessException.getCode(),businessException.getMessage());
        }else{
            return ResultResponse.error(e.getMessage());
        }
    }
}

cloud内部抛出异常不进行处理，Feign获取spring默认包装异常结果如下：

{
 "timestamp": "2017-12-27 15:01:53",
  "status": 500,
  "error": "Internal Server Error",
  "exception": "com.keruyun.loyalty.commons.master.exception.BusinessException",
  "message": "Request processing failed; nested exception is {\"code\":1000, \"message\":\"test Exception\"}",
  "path": "/coupon/cloud/commercial/8469"
  }

重写Feign的ErrorDecoder

@Configuration
@Slf4j
public class ExceptionErrorDecoder implements ErrorDecoder {
        ObjectMapper objectMapper = new ObjectMapper();

        @Override
        public Exception decode(String s, Response response) {

                try {
                        if (response.body() != null) {
                                String targetMsg = null;
                                String body = Util.toString(response.body().asReader());
                                log.error(body);
                                ExceptionInfo ei = this.objectMapper.readValue(body.getBytes("UTF-8"), ExceptionInfo.class);
                                Class clazz = Class.forName(ei.getException());
                                Object obj = clazz.newInstance();
                                String message = ei.getMessage();
                                if (obj instanceof BusinessException) {
                                        targetMsg = message.substring(message.indexOf("{"), message.indexOf("}") + 1);
                                        BusinessException businessException = JsonUtil.toObj(targetMsg, BusinessException.class);
                                        return businessException;
                                }else{
                                        targetMsg=message.substring(message.indexOf(":"),message.length());
                                        return new InternalException(targetMsg);
                                }

                        }
                } catch (Exception var4) {
                        log.error(var4.getMessage());
                        return new InternalException(var4.getMessage());
                }
                return new InternalException("系统异常,请联系管理员");
        }

}

总结：

@controllerAdvice或者HandlerExceptionResolver是不能直接捕获到FeignException,所以需要在Feign层面拿到具体异常重新封装。最后总算把cloud service内部的异常安全(一样的错误码、一样的错误信息)送给了client!!