Spring的异常重试框架Spring Retry简单配置操作

Spring的异常重试框架Spring Retry简单配置操作

相关api见：点击进入

/*

* 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://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:

*

* {@code "message.contains('you can retry this')"}.

*

* and

*

* {@code "@someBean.shouldRetry(#root)"}.

*

* @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：

org.springframework.retry

spring-retry

RELEASE

然后在方法上配置注解@Retryable

@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);

if (StringUtils.isEmpty(string)) throw new RemoteAccessException("发送消息异常");

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hAqTy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。

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。