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java.nioセレクター機能でjavaserversocket（サーバー側）とsockets（クライアント側）を使用しているクライアントサーバーアプリケーションがあります。ObjectInput / Output Streamsを介してシリアル化されたオブジェクトを使用して、クライアントとサーバー間でメッセージを交換しています。

これは、かなり標準的なサーバーからメッセージを受信するためのscalaコードです。

enter code here

var msg:CommunicationMessage = null
    var buf:ByteBuffer  = ByteBuffer.allocate(1024);
    var numBytesRead:Int = 0

    try {
        // Clear the buffer and read bytes from socket
        buf.clear();
        //println("Before Read")



        numBytesRead = sChannel.read(buf)


        //println("After Read  " + numBytesRead)


        numBytesRead match {

          case -1 => 
            println("Something Wrong with the Channel")

          case 0 => 
            //println("Nothing to read")

          case _ =>
            //println("Read some bytes")
            // To read the bytes, flip the buffer
            buf.flip();

            // Read the bytes from the buffer ...;
            // see Getting Bytes from a ByteBuffer
            val bis:ByteArrayInputStream = new ByteArrayInputStream (buf.array());
            val ois:ObjectInputStream = new ObjectInputStream (bis);
            msg = ois.readObject().asInstanceOf[CommunicationMessage];

            println("\n\n")
            println("Received Message from Server")

            msg.msgType match {

                case CommunicationConstants.COMM_MSG_TYPE_RSP =>
                    println("updating server info")
                    updateServerInfo(msg.msgData)

                case CommunicationConstants.COMM_MSG_TYPE_IND =>
                    if (serverAccepted) updateClientUI(msg)

            }

        }

    } catch  {

      case e:StreamCorruptedException =>
        println("Stream Corruption Exception received " + e.getCause())

      case e:IOException => 
        // Connection may have been closed
        println("IO Exception received" + e.getCause())
    }
enter code here

Everything works fine except for situations when the server writes multiple messages within a very short span of time and the client receives them together in the buffer and causes StreamCorruptedException. As I understand , the objectinputstream cannot delimit between multiple serialized objects in the incoming byte stream hence it throws this invalid stream error. Also even I have put the exception for catching it , the program still hangs.

What could be a solution for this. ?

1) Creating my own delimiters in the message based on some length field to identify the message boundary.

2) I also read somewhere to close the socket after every receive and start a new one. Not sure how will this help.

Plz suggest.

Thanks in advance

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1 に答える 1

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パケット化された長さをObjectOutputStreamその内容の前に送信する必要があります。次に、各ストリームに属する着信データの量を正確に把握し、ByteArrayInputStreamそれに応じて構築できます。

于 2012-04-12T01:44:41.847 に答える