Feign調用全局異常處理解決方案

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異常信息形如：

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

對於failed and no fallback available.這種異常信息，是因為項目開啟瞭熔斷：

feign.hystrix.enabled: true

當調用服務時拋出瞭異常，卻沒有定義fallback方法，就會拋出上述異常。由此引出瞭第一個解決方式。

解決方案：

自定義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 {
            // 這裡直接拿到我們拋出的異常信息
            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);
    }
}

定義系統的異常類

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);
    }
}

統一異常攔截轉換對應的異常信息返回前端

public class ResultSet {
    /**
     * 返回的狀態碼
     */
    private Integer resultCode;
    /**
     * 返回的消息
     */
    private String resultMsg;
    /**
     * 返回的數據
     */
    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;
    }
}

全局異常類處理配置：

@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("系統異常，請聯系系統開發人員進行處理", e);
        }
        resultSet.setResultCode(-1);
        resultSet.setResultMsg(e.getMessage());
        resultSet.setData(null);
    }
    return resultSet;
}

這樣就能完成瞭feign接收異常處理的自定義異常信息！

統一處理@FeignClient調用接口異常—-原樣拋出

第三方系統調用我方系統@FeignClient接口時報錯

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

我方系統出現FeignException.

第三方調用者拋出的異常:HystrixRuntimeException

一檢查我們系統確實沒有指定fallback和configuration,並且調用方開啟瞭feign.hystrix.enabled: true

@FeignClient(value = "taxplan-workflow")

修改方法：

第三方調用在Application.java添加處理Feign異常的全局處理方法

@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());
}

這裡使用瞭RequestInterceptor攔截器,可以定制請求頭,如果不想定制,可以改為

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

實現ErrorDecoder接口,其中ExceptionCode是枚舉類.

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枚舉類如下:可以自定義增加刪除

public enum ExceptionCode {
    ILLEGAL_STATE(4001, "非法訪問"),
    PARAM_REQUIRED(4002, "參數不能為空"),
    PARAM_FORMAT_ILLEGAL(4003, "參數格式錯誤"),
    REQUEST_DATA_DUPLICATION(4004, "重復請求"),
    REQUEST_DATA_ERROR(4005, "請求數據錯誤"),
    REQUEST_DATA_NOT_MATCH(4006, "請求數據不一致"),
    RECORD_NOT_EXIST(5001, "記錄不存在"),
    RECORD_EXISTED(5002, "記錄已存在"),
    RECORD_ILLEGAL_STATE(5003, "數據異常"),
    BALANCE_NOT_ENOUGH(5103, "餘額不足"),
    CALL_INNER_ERROR(5800, "調用內部服務接口異常"),
    THIRD_PART_ERROR(5801, "調用第三方接口異常"),
    SYSTEM_ERROR(9999, "系統異常"); 
    public final int code;
    public final String defaultMessage; 
    private ExceptionCode(int code, String defaultMessage) {
        this.code = code;
        this.defaultMessage = defaultMessage;
    }
}

以上為個人經驗，希望能給大傢一個參考，也希望大傢多多支持WalkonNet。

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