可以根据HttpStatus状态码在spring-retry中设置RetryPolicy吗？

Question

是否可以根据错误状态码在弹簧重试(https://github.com/spring-projects/spring-retry)中设置RetryPolicy？例如，我想在HttpStatus.INTERNAL_SERVER_ERROR状态码为503的HttpServerErrorException上重试。因此，它应该忽略所有其他错误代码-- 500 - 502和504 - 511。

Answer 1

RestTemplate有setErrorHandler选项，DefaultResponseErrorHandler是缺省选项。

它的代码如下所示：

public void handleError(ClientHttpResponse response) throws IOException {
    HttpStatus statusCode = getHttpStatusCode(response);
    switch (statusCode.series()) {
        case CLIENT_ERROR:
            throw new HttpClientErrorException(statusCode, response.getStatusText(),
                    response.getHeaders(), getResponseBody(response), getCharset(response));
        case SERVER_ERROR:
            throw new HttpServerErrorException(statusCode, response.getStatusText(),
                    response.getHeaders(), getResponseBody(response), getCharset(response));
        default:
            throw new RestClientException("Unknown status code [" + statusCode + "]");
    }
}

因此，您可以为该方法提供自己的实现，以简化所需的状态代码周围的RetryPolicy。

Answer 2

对于其他面临同样问题的人，我发布了这个答案。实现自定义重试策略，方法如下：

class InternalServerExceptionClassifierRetryPolicy extends ExceptionClassifierRetryPolicy {
public InternalServerExceptionClassifierRetryPolicy() {
    final SimpleRetryPolicy simpleRetryPolicy = new SimpleRetryPolicy();
    simpleRetryPolicy.setMaxAttempts(3);

    this.setExceptionClassifier(new Classifier<Throwable, RetryPolicy>() {
        @Override
        public RetryPolicy classify(Throwable classifiable) {
            if (classifiable instanceof HttpServerErrorException) {
                // For specifically 500 and 504
                if (((HttpServerErrorException) classifiable).getStatusCode() == HttpStatus.INTERNAL_SERVER_ERROR
                        || ((HttpServerErrorException) classifiable)
                                .getStatusCode() == HttpStatus.GATEWAY_TIMEOUT) {
                    return simpleRetryPolicy;
                }
                return new NeverRetryPolicy();
            }
            return new NeverRetryPolicy();
        }
    });
}}

Ans简单地叫它如下：

RetryTemplate template = new RetryTemplate();
template.setRetryPolicy(new InternalServerExceptionClassifierRetryPolicy())

Answer 3

您也可以在SinmpleRetryPolicy的retryableExceptions列表中添加具体的错误码。

Map<Class<? extends Throwable>, Boolean> retryableExceptions = new HashMap<>();
retryableExceptions.put(HttpClientErrorException.Unauthorized.class, true);
retryTemplate.setRetryPolicy(new SimpleRetryPolicy(5, retryableExceptions));