springboot重試組件

最近有一個業務需要有重試機制，感覺應該寫一個能夠重試的組件。

 

首先創建一個註解

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

} 

在常見一個切入點

/**
 *@Author GUOSHAOHUA093
 *@Description 重試切點
 *@Date 14:07 2018/12/8
 */
@Component  //聲明組件
@Aspect
public class TryAgainPointcut {
	
	@Pointcut("execution(* com.pingan.medical.service..*(..))")
	public void businessService() {
	}
	
}

因爲我們希望每次重試都是一個新的事務，所以我們需要高於事務去執行，並且我們項根據傳入的Exception自行來判斷對什麼樣的異常進行重試（目前只支持放入一種哈，後續看心情開發中。。。。）。

/**
 *@Author GUOSHAOHUA093
 *@Description 重試攔截處理方法
 *@Date 14:09 2018/12/8
 */
@Component  //聲明組件
@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 {
      //得到重試次數
      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("這是第"+numAttempts+"次訪問");
            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;
   }

}

 用的時候就很方便啦,寫了exception就會對指定的exception做攔截，不寫就會對所有的exception進行攔截。

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

注意事項，如果用到事務，一定要讓攔截器高於事務執行。

至此就結束了。