Java，收到奇怪的套接字异常：“管道损坏”和“操作超时”

Question

I have a client server application that has 16 threads (8 client, 8 server) and each has a TCP connection in a 1-1 matching (so 8 TCP streams).

I have the server sending X amount of random bytes then close. Meanwhile the client just reads X amount of data then closes. X is predetermined. I am also using dummynet for bandwidth throttling but I am leaving the pipe with plenty of bandwidth (100Mbps). Sometimes it works fine, other times I get these exceptions. I am transferring 1GB spread evenly over all 8 connections in around 3.5 minutes.

The client is throwing this exception:

java.net.SocketException: Operation timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:129)
at miccbull.parralleltcp.client.StreamWorker.run(StreamWorker.java:43)

The server is throwing this exception:

java.net.SocketException: Broken pipe
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
at java.net.SocketOutputStream.write(SocketOutputStream.java:124)
at miccbull.parralleltcp.server.TransmissionWorker.run(TransmissionWorker.java:51)

Server Code:

public void run() {

    OutputStream os = null;

    try {
        socket = sSocket.accept();
        os = socket.getOutputStream();
    } catch (IOException e2) {
        e2.printStackTrace();
    }

    //send the data
    for(int i = 0; i < Server.TRANSMISSIONS; i++){
        System.out.println(sSocket.getLocalPort() + " sending set " + (i+1) + " of " + Server.TRANSMISSIONS);

        try {
            os.write(new byte[Server.FILE_SIZE/Server.numStreams/Server.TRANSMISSIONS]);
            os.flush();
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("Closing server (at write bytes) with socket id: " + sSocket.getLocalPort());
        } 
    }

    System.out.println("Worker " + sSocket.getLocalPort() + " done");

    //close the socket
    try {
        socket.close();
        sSocket.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

Client Code:

    public void run(){

    byte[] bytes = new byte[1024];  //number of bytes to read per client stream
    InputStream is = null;

    //connect to server
    try {
        connectionSocket = new Socket("localhost", id);
        is = connectionSocket.getInputStream();
    } catch (UnknownHostException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }


    //read file from server
    int value = 0;
    int bytesRead = 0;
    try {

        while(bytesRead < (Client.FILE_SIZE/Client.NUM_STREAMS)){
            value = is.read(bytes, 0, 1024);
            if(value == -1){
                System.out.println("******************************** Read is -1 for client " + id);
            }
            else if(value == 0){
                System.out.println("******************************** Read is 0 for client " + id);
            }
            bytesRead += value;
        }
    } catch (IOException e) {
        System.out.println("**** Exception in read in client " + id + " and value value was: " + value);
        if(bytesRead == (Client.FILE_SIZE/Client.NUM_STREAMS)){
            System.out.println("************ NOT ACTUALLY BAD" + id);
        }
        e.printStackTrace();
    }

    //Finished download
    Client.workerDone();
    System.out.println("Worker " + id + " done received " + bytesRead);

What causes these exceptions?

Answer 1

您的客户端永远不会停止读取，因为您不测试返回的<0的read（）。

Answer 2

Here's what I see in your code:

1. I have verified that every call to both socket.getOutputStream() and socket.getInputStream() returns a different stream associated with the socket. You should call them each once per socket and put the result in a local variable.

    OutputStream outputStream = socket.getOutputStream(); // send the data for (int i = 0; i < 10; i++) { .... outputStream.write(...); 

2. There are a number of places where you should return from your run() method but I suspect you knew that.

3. You are not checking the return value from read() to see if it returns -1 on EOF. You should not just make the assumption you are getting the correct number of bytes.

4. I assume you are writing blocks of null characters for a reason.