Question

我有这个java代理处理大量可以在一夜之间运行的文档。问题是，如果网络突然断开连接，我需要代理重试。重试可能有一个最大数量。

int numberOfRetries = 0;
try {
    while(nextdoc != null) {
        // process documents
        numberOfRetries = 0;
    }
} catch (NotesException e) {
    numberOfRetries++;
    if (numberOfRetries > 4) {
        // go back and reprocess current document
    } else {
        // message reached max number of retries. did not successfully finished
    }
}

另外，我当然不想重试整个过程。基本上我需要继续处理正在处理的文档并继续下一个循环

Answer 1

您应该围绕获取文档的每段代码执行重试循环。由于Notes类通常需要getFirst和getNext范例，这意味着您需要两个单独的重试循环。如，

   numberOfRetries = 0;
   maxRetries = 4;   

   // get first document, with retries

   needToRetry = false;
   while (needToRetry)
   {
      try
      {
         while (needToRetry)
         {
            nextDoc = myView.getFirstDocument();
            needToRetry=false;
         }    
      }
      catch (NotesException e) 
      {
         numberOfRetries++;
         if (numberOfRetries < maxRetries) {
            // you might want to sleep here to wait for the network to recover
            // you could use numberOfRetries as a factor to sleep longer on
            // each failure
            needToRetry = true;
         } else {
            // write "Max retries have been exceeded getting first document" to log
            nextDoc = null; // we won't go into the processing loop 
         }
      }
   }

   // process all documents

   while(nextdoc != null) 
   {

      // process nextDoc
      //   insert your code here


      // now get next document, with retries

      while (needToRetry)
      {
         try
         {
            nextDoc = myView.getNextDocument();
            needToRetry=false;
         }  
         catch (NotesException e) 
         {
            numberOfRetries++;
            if (numberOfRetries < maxRetries) {
               // you might want to sleep here to wait for the network to recover
               // you could use numberOfRetries as a factor to sleep longer on
               // each failure
               needToRetry = true;
            } else {
               // write "Max retries have been exceeded getting first document" to log
               nextDoc = false; // we'lll be exiting the processing loop without finishing all docs 
            }
         }
      }
   }

请注意，我将maxRetries视为数据集中所有文档的最大总重试次数，而不是每个文档的最大重试次数。

另请注意，稍微分解一下可能更干净。 E.g。

   numberOfRetries = 0;
   maxRetries = 4;  

   nextDoc = getFirstDocWithRetries(view);   // this contains while loop and try-catch

   while (nextDoc != null)
   { 
       processOneDoc(nextDoc);
       nextDoc = getNextDocWithRetries(view,nextDoc);   // and so does this
   }

Answer 2

我不会推荐你在做什么。

NotesException可能由于多种原因而触发，并且无法保证您将返回到安全状态。

此外，代理需要运行这么长时间的事实意味着您需要更改服务器“最大执行超时”以允许它正确运行。将其设置为非常高的值会使服务器更容易出现性能/死锁问题。

更好的解决方案是批处理工作负载，让代理在批处理上运行一段时间。随时更新，以便当代理回来时，它知道要处理下一批。

如何捕获“NotesException：Notes错误：远程系统不再响应”并重试？

2 个答案: