Java “实施的最佳方式”；“重试”；当到达api端点时？

我正在使用ApacheHttpClient

我有一个Java方法（在Java微服务中），它向外部端点（我不拥有的端点）发出HttpPOST请求。通常情况下，一切正常，但有时端点出现故障并失败。代码如下所示（简化）：

我没有编写原始代码，但正如您所看到的，它似乎发出了一个请求，虽然请求重试计数大于0（看起来总是这样），但它将尝试向url发出帖子。由于某种原因，它看起来有一个断点，因此在它跳入

try

块之后，它总是会中断，并且没有重试机制

---

Java中是否有一种通用的设计模式来实现命中外部端点的重试模式？我知道在Javascript中，您可以使用Fetch API并返回一个承诺，Java有类似的功能吗？

像GCP和AWS这样的云平台通常都有自己的重试策略，这应该是首选方法

如果您想扮演自己的重试策略角色，指数退避可以是一个很好的起点

它可以是基于注释的，您可以在其中注释客户机方法。例如， 您可以按如下方式注释API方法：

public class RetryMethodInterceptor implements MethodInterceptor {

  private static final Logger logger = Logger.getLogger(RetryMethodInterceptor.class.getName());

  @Override
  public Object invoke(MethodInvocation methodInvocator) throws Throwable {
    Retry retryAnnotation = methodInvocator.getMethod().getAnnotation(Retry.class);
    Set<Class<? extends Throwable>> retriableExceptions =
        Sets.newHashSet(retryAnnotation.retryOnExceptions());

    String className = methodInvocator.getThis().getClass().getCanonicalName();
    String methodName = methodInvocator.getMethod().getName();

    int tryCount = 0;
    while (true) {
      try {
        return methodInvocator.proceed();
      } catch (Throwable ex) {
        tryCount++;
        boolean isExceptionInAllowedList = isRetriableException(retriableExceptions, ex.getClass());
        if (!isExceptionInAllowedList) {
          System.out.println(String.format(
              "Exception not in retry list for class: %s - method: %s - retry count: %s",
              className, methodName, tryCount));
          throw ex;
        } else if (isExceptionInAllowedList && tryCount > retryAnnotation.maxTries()) {
          System.out.println(String
                  .format(
                      "Exhausted retries, rethrowing exception for class: %s - method: %s - retry count: %s",
                      className, methodName, tryCount));
          throw ex;
        }
        System.out.println(String.format("Retrying for class: %s - method: %s - retry count: %s",
            className, methodName, tryCount));
      }
    }
  }

  private boolean isRetriableException(Set<Class<? extends Throwable>> allowedExceptions,
      Class<? extends Throwable> caughtException) {
    for (Class<? extends Throwable> look : allowedExceptions) {
      // Only compare the class names we do not want to compare superclass so Class#isAssignableFrom
      // can't be used.
      if (caughtException.getCanonicalName().equalsIgnoreCase(look.getCanonicalName())) {
        return true;
      }
    }
    return false;
  }
}

@重试（maxTries=3，retryOnExceptions={RpcException.class}） public UserInfo getUserInfo（字符串userId）

@已记录
@保留（RetentionPolicy.RUNTIME）
@目标（ElementType.METHOD）
公共@接口重试{
int maxTries（）默认值为0；
/**
*如果引发以下异常之一，请尝试重试。
*@返回适用异常的数组
*/
ClassAPI的终结点是什么，是AWS、GCP等吗？重试已经是
ApacheHttpClient
的一部分。promise是JS代表asyn操作，promise本身不会在失败时重试。如果你想看的话，我用我已有的代码更新了我的问题。
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Retry {

  int maxTries() default 0;

  /**
   * Attempt retry if one of the following exceptions is thrown.
   * @return array of applicable exceptions
   */
  Class<? extends Throwable> [] retryOnExceptions() default {Throwable.class};
}

public class RetryMethodInterceptor implements MethodInterceptor {

  private static final Logger logger = Logger.getLogger(RetryMethodInterceptor.class.getName());

  @Override
  public Object invoke(MethodInvocation methodInvocator) throws Throwable {
    Retry retryAnnotation = methodInvocator.getMethod().getAnnotation(Retry.class);
    Set<Class<? extends Throwable>> retriableExceptions =
        Sets.newHashSet(retryAnnotation.retryOnExceptions());

    String className = methodInvocator.getThis().getClass().getCanonicalName();
    String methodName = methodInvocator.getMethod().getName();

    int tryCount = 0;
    while (true) {
      try {
        return methodInvocator.proceed();
      } catch (Throwable ex) {
        tryCount++;
        boolean isExceptionInAllowedList = isRetriableException(retriableExceptions, ex.getClass());
        if (!isExceptionInAllowedList) {
          System.out.println(String.format(
              "Exception not in retry list for class: %s - method: %s - retry count: %s",
              className, methodName, tryCount));
          throw ex;
        } else if (isExceptionInAllowedList && tryCount > retryAnnotation.maxTries()) {
          System.out.println(String
                  .format(
                      "Exhausted retries, rethrowing exception for class: %s - method: %s - retry count: %s",
                      className, methodName, tryCount));
          throw ex;
        }
        System.out.println(String.format("Retrying for class: %s - method: %s - retry count: %s",
            className, methodName, tryCount));
      }
    }
  }

  private boolean isRetriableException(Set<Class<? extends Throwable>> allowedExceptions,
      Class<? extends Throwable> caughtException) {
    for (Class<? extends Throwable> look : allowedExceptions) {
      // Only compare the class names we do not want to compare superclass so Class#isAssignableFrom
      // can't be used.
      if (caughtException.getCanonicalName().equalsIgnoreCase(look.getCanonicalName())) {
        return true;
      }
    }
    return false;
  }
}