reading multiple lines from TCP stream

Question

looking to build a tcp listener which will read information from a connection and respond with some data.

I've got the program working on a single line input but when I send multiple lines it doesn't work.

Here is the code I was using

try {
    Socket clientConnection = null;
    clientConnection = serverSocket.accept();
    clientConnection.setSoTimeout(5 * 1000);
    String tmpLine=null;
    BufferedReader inFromClient = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
    for (tmpLine = inFromClient.readLine(); tmpLine != null; tmpLine = inFromClient.readLine()) {
        searchLine += tmpLine;
        logMsg = "DBUG : T" + threadName + " readline : " + searchLine;
        stubLog.addMessage(logMsg, coreProperties.getLogger(),"DEBUG");
    }
} catch (Exception e) {
    logMsg = "ERRR : T" + threadName + " : tcpStubWorker: error in getting data : " + e.getMessage();
    stubLog.addMessage(logMsg, coreProperties.getLogger(),"ERROR");
    e.printStackTrace(); 
}

When I send in this message from a harness:

String logonMsg = "msg: 0800    P3A^SNAT2 >>> S3A^SNAT204        15/10/12 16:55:07.00 rec: 001021\n"
+ "bit 007: 1012165507  \n"
+ "bit 011: 498432  \n"
+ "bit 033: (11)59501100554  \n"
+ "bit 070: 001  \n"
+ "bit 100: (11)59503646554  \n";

I get this in the logs:

DEBUG com.stubby.tcp.tcpStub  - 14:33:43:494 - DBUG : T00000026 readline : nullmsg: 0800    P3A^SNAT2 >>> S3A^SNAT204        15/10/12 16:55:07.00 rec: 001021
DEBUG com.stubby.tcp.tcpStub  - 14:33:43:509 - DBUG : T00000026 readline : nullmsg: 0800    P3A^SNAT2 >>> S3A^SNAT204        15/10/12 16:55:07.00 rec: 001021bit 007: 1012165507  
DEBUG com.stubby.tcp.tcpStub  - 14:33:43:510 - DBUG : T00000026 readline : nullmsg: 0800    P3A^SNAT2 >>> S3A^SNAT204        15/10/12 16:55:07.00 rec: 001021bit 007: 1012165507  bit 011: 498432  
DEBUG com.stubby.tcp.tcpStub  - 14:33:43:534 - DBUG : T00000026 readline : nullmsg: 0800    P3A^SNAT2 >>> S3A^SNAT204        15/10/12 16:55:07.00 rec: 001021bit 007: 1012165507  bit 011: 498432  bit 033: (11)59501100554  
DEBUG com.stubby.tcp.tcpStub  - 14:33:43:552 - DBUG : T00000026 readline : nullmsg: 0800    P3A^SNAT2 >>> S3A^SNAT204        15/10/12 16:55:07.00 rec: 001021bit 007: 1012165507  bit 011: 498432  bit 033: (11)59501100554  bit 070: 001  
DEBUG com.stubby.tcp.tcpStub  - 14:33:43:603 - DBUG : T00000026 readline : nullmsg: 0800    P3A^SNAT2 >>> S3A^SNAT204        15/10/12 16:55:07.00 rec: 001021bit 007: 1012165507  bit 011: 498432  bit 033: (11)59501100554  bit 070: 001  bit 100: (11)59503646554   
ERROR com.stubby.tcp.tcpStub  - 14:33:48:627 - ERRR : T00000026 : tcpStubWorker: error in getting data : Read timed out

Any ideas why the for loop is failing to recognise on tmpLine != null?

I suppose I could decrease the timeout and make that error a warning but that doesn't sound quite right!

Thanks.

thanks for feedback, the peer is using this code to send the data

Socket clientSocket = new Socket("10.52.88.102", 8888);
DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
outToServer.writeBytes(logonMsg + '\n');
modifiedSentence = inFromServer.readLine();
System.out.println("From server: \"" + modifiedSentence +"\"");
clientSocket.close();

but still getting the error :( so i suspect I'm not closing the connection correctly??

Answer 1

对方没有关闭连接，并且您的读取循环只会在对方断开时停止。