Spring Cloud Gateway自定義異常處理Exception Handler

飛雲~風之谷發表於2021-08-09
SpringCloudGatewayException

版本: Spring Cloud 2020.0.3

常見的方法有 實現自己的 DefaultErrorWebExceptionHandler 或 僅實現ErrorAttributes.

方法1: ErrorWebExceptionHandler (僅供示意)

自定義一個 GlobalErrorAttributes:


@Component
public class GlobalErrorAttributes extends DefaultErrorAttributes{

    @Override
    public Map<String, Object> getErrorAttributes(ServerRequest request, ErrorAttributeOptions options) {
        Throwable error = super.getError(request);

        Map<String, Object> map = super.getErrorAttributes(request, options);
        map.put("status", HttpStatus.BAD_REQUEST.value());
        map.put("message", error.getMessage());
        return map;
    }
}

實現一個


@Component
@Order(-2)
public class GlobalErrorWebExceptionHandler extends AbstractErrorWebExceptionHandler {

    public GlobalErrorWebExceptionHandler(GlobalErrorAttributes gea, ApplicationContext applicationContext,
                                          ServerCodecConfigurer serverCodecConfigurer) {
        super(gea, new WebProperties.Resources(), applicationContext);
        super.setMessageWriters(serverCodecConfigurer.getWriters());
        super.setMessageReaders(serverCodecConfigurer.getReaders());
    }

    //渲染html或json
    @Override
    protected RouterFunction<ServerResponse> getRoutingFunction(final ErrorAttributes errorAttributes) {
        return RouterFunctions.route(RequestPredicates.all(), this::renderErrorResponse);
    }

    private Mono<ServerResponse> renderErrorResponse(final ServerRequest request) {

        final Map<String, Object> errorPropertiesMap = getErrorAttributes(request, ErrorAttributeOptions.defaults());

        return ServerResponse.status(HttpStatus.BAD_REQUEST)
                .contentType(MediaType.APPLICATION_JSON)
                .body(BodyInserters.fromValue(errorPropertiesMap));
    }
}

方法2, 僅實現一個 ErrorAttributes, 以覆蓋預設的 DefaultErrorAttributes


//Spring 預設的就很好了.
@Component
public class GatewayErrorAttributes extends DefaultErrorAttributes {

    private static final Logger logger = LoggerFactory.getLogger(GatewayErrorAttributes.class);

    @Override
    public Map<String, Object> getErrorAttributes(ServerRequest request,  ErrorAttributeOptions options) {
        Throwable error = super.getError(request);
        Map<String, Object> errorAttributes = new HashMap<>(8);
        errorAttributes.put("message", error.getMessage());
        errorAttributes.put("method", request.methodName());
        errorAttributes.put("path", request.path());

        MergedAnnotation<ResponseStatus> responseStatusAnnotation = MergedAnnotations
                .from(error.getClass(), MergedAnnotations.SearchStrategy.TYPE_HIERARCHY).get(ResponseStatus.class);

        HttpStatus errorStatus = determineHttpStatus(error, responseStatusAnnotation);

        //必須設定, 否則會報錯, 因為 DefaultErrorWebExceptionHandler 的 renderErrorResponse 方法會獲取此屬性, 重新實現 DefaultErrorWebExceptionHandler也可.
        errorAttributes.put("status", errorStatus.value());
        errorAttributes.put("code", errorStatus.value());

        //html view用
        errorAttributes.put("timestamp", new Date());
        //html view 用
        errorAttributes.put("requestId", request.exchange().getRequest().getId());

        errorAttributes.put("error", errorStatus.getReasonPhrase());
        errorAttributes.put("exception", error.getClass().getName());

        return errorAttributes;
    }

    //從DefaultErrorWebExceptionHandler中複製過來的
    private HttpStatus determineHttpStatus(Throwable error, MergedAnnotation<ResponseStatus> responseStatusAnnotation) {
        if (error instanceof ResponseStatusException) {
            return ((ResponseStatusException) error).getStatus();
        }
        return responseStatusAnnotation.getValue("code", HttpStatus.class).orElse(HttpStatus.INTERNAL_SERVER_ERROR);
    }
    
}

這樣就可以了.

注意注意: 必須設定 errorAttributes.put("status", errorStatus.value()) , 否則會報錯, 因為 DefaultErrorWebExceptionHandler 的 renderErrorResponse 方法會獲取此屬性. 除非你自己像方法一一樣重新實現 DefaultErrorWebExceptionHandler.

然後在閘道器中訪問一個不存在的服務, 即可看到效果.

curl 'http://127.0.0.1:8900/fundmain22/abc/gogogo?id=1000' --header 'Accept: application/json'
{"exception":"org.springframework.web.server.ResponseStatusException","path":"/fundmain22/abc/gogogo","code":404,"method":"GET","requestId":"094e53e5-1","message":"404 NOT_FOUND","error":"Not Found","status":404,"timestamp":"2021-08-09T11:07:44.106+0000"}

感謝網路上的各種文章...

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