相关api见:点击进入
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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) @Documented public @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的简单配置做一个讲解:
首先引入maven依赖:
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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( "发送消息异常" ); } if (Integer.parseInt(errcode) == 0 ) { return true ; } else { throw new RemoteAccessException( "发送消息异常" ); } } else { throw new RemoteAccessException( "发送消息异常" ); } } catch (Exception e) { logger.error( "wz:customSend:{}" , ExceptionUtils.getStackTrace(e)); throw new RemoteAccessException( "发送消息异常" ); } } |
注解内容介绍:
@Retryable注解
被注解的方法发生异常时会重试
value:指定发生的异常进行重试
include:和value一样,默认空,当exclude也为空时,所有异常都重试
exclude:指定异常不重试,默认空,当include也为空时,所有异常都重试
maxAttemps:重试次数,默认3
backoff:重试补偿机制,默认没有
@Backoff注解
delay:指定延迟后重试
multiplier:指定延迟的倍数,比如delay=5000l,multiplier=2时,第一次重试为5秒后,第二次为10秒,第三次为20秒
注意:
1、使用了@Retryable的方法不能在本类被调用,不然重试机制不会生效。也就是要标记为@Service,然后在其它类使用@Autowired注入或者@Bean去实例才能生效。
2、使用了@Retryable的方法里面不能使用try...catch包裹,要在发放上抛出异常,不然不会触发。
3、在重试期间这个方法是同步的,如果使用类似Spring Cloud这种框架的熔断机制时,可以结合重试机制来重试后返回结果。
4、Spring Retry不仅能注入方式去实现,还可以通过API的方式实现,类似熔断处理的机制就基于API方式实现会比较宽松。
以上这篇Spring的异常重试框架Spring Retry简单配置操作就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/fz13768884254/article/details/83176459