Feign调用全局异常处理解决方案

异常信息形如：

TestService#addRecord(ParamVO) failed and no fallback available.；

对于failed and no fallback available.这种异常信息，是因为项目开启了熔断：

feign.hystrix.enabled: true

当调用服务时抛出了异常，却没有定义fallback方法，就会抛出上述异常。由此引出了第一个解决方式。

解决方案：

自定义Feign解析器：

import com.alibaba.fastjson.JSONException;
import com.alibaba.fastjson.JSONObject;
import com.crecgec.baseboot.jsoncore.exception.BaseException;
import feign.Response;
import feign.Util;
import feign.codec.ErrorDecoder;
import org.springframework.context.annotation.Configuration;
import java.io.IOException;
@Configuration
public class FeignErrorDecoder implements ErrorDecoder {
    @Override
    public Exception decode(String methodKey, Response response) {
        try {
            // 这里直接拿到我们抛出的异常信息
            String message = Util.toString(response.body().asReader());
            try {
                JSONObject jsonObject = JSONObject.parseObject(message);
                return new BaseException(jsonObject.getString("resultMsg"), jsonObject.getInteger("resultCode"));
            } catch (JSONException e) {
                e.printStackTrace();
            }
        } catch (IOException ignored) {
        }
        return decode(methodKey, response);
    }
}

定义系统的异常类

public class BaseException extends RuntimeException {
    private int status ;
    public int getStatus() {
        return status;
    }

    public void setStatus(int status) {
        this.status = status;
    }

    public BaseException() {
    }

    public BaseException(String message, int status) {
        super(message);
        this.status = status;
    }

    public BaseException(String message) {
        super(message);
    }

    public BaseException(String message, Throwable cause) {
        super(message, cause);
    }

    public BaseException(Throwable cause) {
        super(cause);
    }

    public BaseException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}

统一异常拦截转换对应的异常信息返回前端

public class ResultSet {
    /**
     * 返回的状态码
     */
    private Integer resultCode;
    /**
     * 返回的消息
     */
    private String resultMsg;
    /**
     * 返回的数据
     */
    private Object data;
    public ResultSet() {
    }
    public ResultSet(Integer resultCode, String resultMsg) {
        this.resultCode = resultCode;
        this.resultMsg = resultMsg;
    }
    public ResultSet(Integer resultCode, String resultMsg, Object data) {
        this.resultCode = resultCode;
        this.resultMsg = resultMsg;
        this.data = data;
    }
    public Integer getResultCode() {
        return resultCode;
    }
    public void setResultCode(Integer resultCode) {
        this.resultCode = resultCode;
    }
    public String getResultMsg() {
        return resultMsg;
    }
    public void setResultMsg(String resultMsg) {
        this.resultMsg = resultMsg;
    }
    public Object getData() {
        return data;
    }
    public void setData(Object data) {
        this.data = data;
    }
}

全局异常类处理配置：

@ExceptionHandler(value = BaseException.class)
public ResultSet defaultErrorHandler(HttpServletRequest req, HttpServletResponse resp, BaseException e) {
    ResultSet resultSet = new ResultSet();
    if (e.getStatus() == 400) {
        resultSet.setResultCode(-1);
        resultSet.setResultMsg(e.getMessage());
        resultSet.setData(null);
        resp.setStatus(400);
    } else {
        resp.setStatus(500);
        if(logger.isErrorEnabled()){
            logger.error("系统异常，请联系系统开发人员进行处理", e);
        }
        resultSet.setResultCode(-1);
        resultSet.setResultMsg(e.getMessage());
        resultSet.setData(null);
    }
    return resultSet;
}

这样就能完成了feign接收异常处理的自定义异常信息！

统一处理@FeignClient调用接口异常----原样抛出

第三方系统调用我方系统@FeignClient接口时报错

com.netflix.hystrix.exception.HystrixRuntimeException: WorkFlowTaskOperateService#processWorkFlowTaskSyncCallback(TaskProcessDTO) failed and no fallback available.

我方系统出现FeignException.

第三方调用者抛出的异常:HystrixRuntimeException

一检查我们系统确实没有指定fallback和configuration,并且调用方开启了feign.hystrix.enabled: true

@FeignClient(value = "taxplan-workflow")

修改方法：

第三方调用在Application.java添加处理Feign异常的全局处理方法

@Bean
public Feign.Builder feignBuilder() {
    return Feign.builder().requestInterceptor(new RequestInterceptor() {
        @Override
        public void apply(RequestTemplate requestTemplate) {
            Map<String, String> customHeaders = WebUtils.getCustomHeaders();
            customHeaders.forEach((k, v) -> {
                requestTemplate.header(k, v);
            });
        }
    }).errorDecoder(new CustomErrorDecoder());
}

这里使用了RequestInterceptor拦截器,可以定制请求头,如果不想定制,可以改为

return Feign.builder().errorDecoder(new CustomErrorDecoder());

实现ErrorDecoder接口,其中ExceptionCode是枚举类.

public Exception decode(String methodKey, Response response) {
        if (response.status() >= 400 && response.status() <= 499) {
            return new BaseBizException(ExceptionCode.CALL_INNER_ERROR, "Client error.httpStatusCode:" + response.status());
        } else {
            if (response.status() >= 500 && response.status() <= 599 && response.body() != null) {
                try {
                    String content = CharStreams.toString(new InputStreamReader(response.body().asInputStream(), StandardCharsets.UTF_8));
                    Map responseBody = (Map) JSONObject.parseObject(content, Map.class);
                    if (responseBody.containsKey("code")) {
                        return new BaseBizException(responseBody.get("code").toString(), Objects.toString(responseBody.get("msg")));
                    }
                } catch (Exception var5) {
                }
            }

            return new BaseBizException(ExceptionCode.CALL_INNER_ERROR);
        }
    }

ExceptionCode枚举类如下:可以自定义增加删除

public enum ExceptionCode {
    ILLEGAL_STATE(4001, "非法访问"),
    PARAM_REQUIRED(4002, "参数不能为空"),
    PARAM_FORMAT_ILLEGAL(4003, "参数格式错误"),
    REQUEST_DATA_DUPLICATION(4004, "重复请求"),
    REQUEST_DATA_ERROR(4005, "请求数据错误"),
    REQUEST_DATA_NOT_MATCH(4006, "请求数据不一致"),
    RECORD_NOT_EXIST(5001, "记录不存在"),
    RECORD_EXISTED(5002, "记录已存在"),
    RECORD_ILLEGAL_STATE(5003, "数据异常"),
    BALANCE_NOT_ENOUGH(5103, "余额不足"),
    CALL_INNER_ERROR(5800, "调用内部服务接口异常"),
    THIRD_PART_ERROR(5801, "调用第三方接口异常"),
    SYSTEM_ERROR(9999, "系统异常");
    public final int code;
    public final String defaultMessage;
    private ExceptionCode(int code, String defaultMessage) {
        this.code = code;
        this.defaultMessage = defaultMessage;
    }
}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。