相關api見：點擊進入
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/* * Copyright 2014 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.retry.annotation; import java.lang.annotation.Documented;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target; /** * Annotation for a method invocation that is retryable. * * @author Dave Syer * @author Artem Bilan * @author Gary Russell * @since 1.1 * */@Target({ ElementType.METHOD, ElementType.TYPE })@Retention(RetentionPolicy.RUNTIME)@Documentedpublic @interface Retryable { /** * Retry interceptor bean name to be applied for retryable method. Is mutually * exclusive with other attributes. * @return the retry interceptor bean name */ String interceptor() default ""; /** * Exception types that are retryable. Synonym for includes(). Defaults to empty (and * if excludes is also empty all exceptions are retried). * @return exception types to retry */ Class<? extends Throwable>[] value() default {}; /** * Exception types that are retryable. Defaults to empty (and if excludes is also * empty all exceptions are retried). * @return exception types to retry */ Class<? extends Throwable>[] include() default {}; /** * Exception types that are not retryable. Defaults to empty (and if includes is also * empty all exceptions are retried). * @return exception types to retry */ Class<? extends Throwable>[] exclude() default {}; /** * A unique label for statistics reporting. If not provided the caller may choose to * ignore it, or provide a default. * * @return the label for the statistics */ String label() default ""; /** * Flag to say that the retry is stateful: i.e. exceptions are re-thrown, but the * retry policy is applied with the same policy to subsequent invocations with the * same arguments. If false then retryable exceptions are not re-thrown. * @return true if retry is stateful, default false */ boolean stateful() default false; /** * @return the maximum number of attempts (including the first failure), defaults to 3 */ int maxAttempts() default 3; /** * @return an expression evaluated to the maximum number of attempts (including the first failure), defaults to 3 * Overrides {@link #maxAttempts()}. * @since 1.2 */ String maxAttemptsExpression() default ""; /** * Specify the backoff properties for retrying this operation. The default is a * simple {@link Backoff} specification with no properties - see it's documentation * for defaults. * @return a backoff specification */ Backoff backoff() default @Backoff(); /** * Specify an expression to be evaluated after the {@code SimpleRetryPolicy.canRetry()} * returns true - can be used to conditionally suppress the retry. Only invoked after * an exception is thrown. The root object for the evaluation is the last {@code Throwable}. * Other beans in the context can be referenced. * For example: * <pre class=code> * {@code "message.contains('you can retry this')"}. * </pre> * and * <pre class=code> * {@code "@someBean.shouldRetry(#root)"}. * </pre> * @return the expression. * @since 1.2 */ String exceptionExpression() default ""; } |
下面就 Retryable的簡單配置做一個講解：
首先引入maven依賴：
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<dependency> <groupId>org.springframework.retry</groupId> <artifactId>spring-retry</artifactId> <version>RELEASE</version> </dependency> |
然后在方法上配置注解@Retryable
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@Override@SuppressWarnings("Duplicates")@Retryable(value = {RemoteAccessException.class}, maxAttempts = 3, backoff = @Backoff(delay = 3000l, multiplier = 0))public boolean customSendText(String openid, String content) throws RemoteAccessException { String replyString = "{\n" + "\"touser\":" + openid + ",\n" + "\"msgtype\":\"text\",\n" + "\"text\":\n" + "{\n" + "\"content\":" + content + "\n" + "}\n" + "}"; try { logger.info("wx:customSend=request:{}", replyString.toString()); HttpsClient httpClient = HttpsClient.getAsyncHttpClient(); String url = Constant.WX_CUSTOM_SEND; String token = wxAccessokenService.getAccessToken(); url = url.replace("ACCESS_TOKEN", token); logger.info("wx:customSend=url:{}", url); String string = httpClient.doPost(url, replyString); logger.info("wx:customSend=response:{}", string); JSONObject jsonTexts = (JSONObject) JSON.parse(string); if (jsonTexts.get("errcode") != null) { String errcode = jsonTexts.get("errcode").toString(); if (errcode == null) { throw new RemoteAccessException("發送消息異常"); } if (Integer.parseInt(errcode) == 0) { return true; } else { throw new RemoteAccessException("發送消息異常"); } } else { throw new RemoteAccessException("發送消息異常"); } } catch (Exception e) { logger.error("wz:customSend:{}", ExceptionUtils.getStackTrace(e)); throw new RemoteAccessException("發送消息異常"); }} |
注解內容介紹：
@Retryable注解
被注解的方法發生異常時會重試
value：指定發生的異常進行重試
include：和value一樣，默認空，當exclude也為空時，所有異常都重試
exclude：指定異常不重試，默認空，當include也為空時，所有異常都重試
maxAttemps：重試次數，默認3
backoff：重試補償機制，默認沒有
@Backoff注解
delay:指定延遲后重試
multiplier:指定延遲的倍數，比如delay=5000l,multiplier=2時，第一次重試為5秒后，第二次為10秒，第三次為20秒
注意：
1、使用了@Retryable的方法不能在本類被調用，不然重試機制不會生效。也就是要標記為@Service，然后在其它類使用@Autowired注入或者@Bean去實例才能生效。
2、使用了@Retryable的方法里面不能使用try...catch包裹，要在發放上拋出異常，不然不會觸發。
3、在重試期間這個方法是同步的，如果使用類似Spring Cloud這種框架的熔斷機制時，可以結合重試機制來重試后返回結果。
4、Spring Retry不僅能注入方式去實現，還可以通過API的方式實現，類似熔斷處理的機制就基于API方式實現會比較寬松。
以上這篇Spring的異常重試框架Spring Retry簡單配置操作就是小編分享給大家的全部內容了，希望能給大家一個參考，也希望大家多多支持服務器之家。
原文鏈接：https://blog.csdn.net/fz13768884254/article/details/83176459
