2019獨角獸企業(yè)重金招聘Python工程師標準>>>

第一步、引入maven依賴

<parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.3.RELEASE</version> </parent> <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId> </dependency> <!-- https://mvnrepository.com/artifact/org.springframework.retry/spring-retry --> <dependency><groupId>org.springframework.retry</groupId><artifactId>spring-retry</artifactId><version>1.1.2.RELEASE</version> </dependency> <dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.8.6</version> </dependency>

• ?

第二步、添加@Retryable和@Recover注解

package hello;import org.springframework.remoting.RemoteAccessException; import org.springframework.retry.annotation.Backoff; import org.springframework.retry.annotation.Recover; import org.springframework.retry.annotation.Retryable; import org.springframework.stereotype.Service;@Service public class RemoteService { @Retryable(value= {RemoteAccessException.class},maxAttempts = 3,backoff = @Backoff(delay = 5000l,multiplier = 1)) public void call() throws Exception {System.out.println("do something...");throw new RemoteAccessException("RPC調(diào)用異常"); } @Recover public void recover(RemoteAccessException e) {System.out.println(e.getMessage()); } }

• ?

@Retryable注解?
被注解的方法發(fā)生異常時會重試?
value:指定發(fā)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(shù)，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(shù)，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

@Recover?
當重試到達指定次數(shù)時，被注解的方法將被回調(diào)，可以在該方法中進行日志處理。需要注意的是發(fā)生的異常和入?yún)㈩愋鸵恢聲r才會回調(diào)

第三步、SpringBoot方式啟動容器、測試

添加@EnableRetry注解，啟用重試功能

package hello;import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import org.springframework.retry.annotation.EnableRetry;@SpringBootApplication @EnableRetry public class Application {public static void main(String[] args) throws Exception {ApplicationContext annotationContext = new AnnotationConfigApplicationContext("hello");RemoteService remoteService = annotationContext.getBean("remoteService", RemoteService.class);remoteService.call();} }

• 運行結果：?
• 16:50:51.012 [main] DEBUG org.springframework.retry.support.RetryTemplate - Retry: count=0?
  do something…?
  16:50:51.025 [main] DEBUG org.springframework.retry.backoff.ExponentialBackOffPolicy - Sleeping for 5000?
  16:50:56.026 [main] DEBUG org.springframework.retry.support.RetryTemplate - Checking for rethrow: count=1?
  16:50:56.026 [main] DEBUG org.springframework.retry.support.RetryTemplate - Retry: count=1?
  do something…?
  16:50:56.026 [main] DEBUG org.springframework.retry.backoff.ExponentialBackOffPolicy - Sleeping for 5000?
  16:51:01.026 [main] DEBUG org.springframework.retry.support.RetryTemplate - Checking for rethrow: count=2?
  16:51:01.027 [main] DEBUG org.springframework.retry.support.RetryTemplate - Retry: count=2?
  do something…?
  16:51:01.027 [main] DEBUG org.springframework.retry.support.RetryTemplate - Checking for rethrow: count=3?
  16:51:01.027 [main] DEBUG org.springframework.retry.support.RetryTemplate - Retry failed last attempt: count=3?
  RPC調(diào)用異常

參考?
https://github.com/spring-projects/spring-retry

?

這邊有個坑：僅僅對類的直接調(diào)用方法有效，方法內(nèi)部調(diào)用自己內(nèi)部方法不會被代理aop和重試

轉載于:https://my.oschina.net/91jason/blog/1512059

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