Spring重试支持Spring Retry

ゝ一世哀愁。 2022-07-17 03:55 183阅读 0赞

## 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>
    
    <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][Link 1]

[Link 1]: http://blog.csdn.net/u014513883/article/details/52712870