springboot重试组件

最近有一个业务需要有重试机制，感觉应该写一个能够重试的组件。

首先创建一个注解

/**
 * @Author GUOSHAOHUA093
 * @Description 重试拦截
 * @Date 9:14 2018/12/8
 */
@Retention(RetentionPolicy.RUNTIME)
public @interface IsTryAgain {
    int times() default 1;
    Class<? extends Exception> exception() default Exception.class;

}

在常见一个切入点

/**
 *@Author GUOSHAOHUA093
 *@Description 重试切点
 *@Date 14:07 2018/12/8
 */
@Component  //声明组件
@Aspect
public class TryAgainPointcut {
	
	@Pointcut("execution(* com.pingan.medical.service..*(..))")
	public void businessService() {
	}
	
}

因为我们希望每次重试都是一个新的事务，所以我们需要高于事务去执行，并且我们项根据传入的Exception自行来判断对什么样的异常进行重试（目前只支持放入一种哈，后续看心情开发中。。。。）。

/**
 *@Author GUOSHAOHUA093
 *@Description 重试拦截处理方法
 *@Date 14:09 2018/12/8
 */
@Component  //声明组件
@Aspect
class RetryAgainExecutor implements Ordered {

   private static final Logger logger = LoggerFactory.getLogger(RetryAgainExecutor.class);
   
   private static final int DEFAULT_MAX_RETRIES = 2;

   private int maxRetries = DEFAULT_MAX_RETRIES;
   private int order = 2;

   public void setMaxRetries(int maxRetries) {
      this.maxRetries = maxRetries;
   }
   
   public int getOrder() {
      return this.order;
   }
   
   @Around("@annotation(com.pingan.medical.config.interceptor.tryAgain.IsTryAgain)")
   public Object doConcurrentOperation(ProceedingJoinPoint pjp) throws Throwable {
      //得到重试次数
      MethodSignature signature = (MethodSignature) pjp.getSignature();
      Method method = signature.getMethod();
      IsTryAgain isTryAgain = method.getAnnotation(IsTryAgain.class);
      int maxTimes = isTryAgain.times();
      int numAttempts = 0;
      Exception retryException;
      do {
         numAttempts++;
         try {
            logger.info("这是第"+numAttempts+"次访问");
            return pjp.proceed();
         }catch(Exception ex) {
            if (isTryAgain.exception().isInstance(Object.class) || isTryAgain.exception().isInstance(ex)) {
               retryException = ex;
            } else {
               throw ex;
            }

         }
      }while(numAttempts < maxTimes);

      
      throw retryException;
   }

}

用的时候就很方便啦,写了exception就会对指定的exception做拦截，不写就会对所有的exception进行拦截。

@IsTryAgain(times = 2,exception = CustomException.class)
@Transactional
public ApiResult test() throw CustomException(){

注意事项，如果用到事务，一定要让拦截器高于事务执行。

至此就结束了。

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