Spring重试支持Spring Retry

第一步、引入maven依赖

<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调用异常");
}
@Recover
public void recover(RemoteAccessException e) {
        System.out.println(e.getMessage());
}
}

@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

@Recover
当重试到达指定次数时，被注解的方法将被回调，可以在该方法中进行日志处理。需要注意的是发生的异常和入参类型一致时才会回调

第三步、SpringBoot方式启动容器、测试

添加@EnableRetry注解，启用重试功能

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();
    }
}

运行结果：
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调用异常

参考
https://github.com/spring-projects/spring-retry

补充
对于非幂等的请求（比如新增，更新操作），千万不要使用重试，对数据一致性会造成很大影响。另外对Spring Retry实现原理感兴趣的可以看下这篇博客