Question

I write client-server appliaction. Client is on android, server on plain Java. I want to client make connection with server next send him some file then server write this file on server-disc and then send to client another file. For now client make connection then send file to server but here starts problems. When I want to server send file to client I get “socket is close” exception.

Here is my code:

server:

public class ThreadHandler implements Runnable
{
public ThreadHandler(Socket i)
{ 
    sk = i; 
}

public void run()
{  
    try
    {
        File file = getFile();
        ParseData data = parseXML(file);

        if(data.getEvent().equals("registration"))
        {
            sendRegistrationResponse();
        }
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }
}

public File getFile() throws Exception
{
    File file=null;

    InputStream input = sk.getInputStream();

    file = new File("C://protocolFile/" + "temp.xml");
    FileOutputStream out = new FileOutputStream(file);

    byte[] buffer = new byte[sk.getReceiveBufferSize()];

    int bytesReceived = 0;

    while((bytesReceived = input.read(buffer))>0) {
        out.write(buffer,0,bytesReceived);
    }

    input.close();
    input = null;
    out.flush();
    out.close();
    out = null;
    System.gc();

    return file;
}

public void sendRegistrationResponse() throws Exception
{
    String fileName = createRegistrationResponseXML();
    sendToApp(fileName);
}

public void sendToApp(String fileName) throws Exception
{
    OutputStream output = sk.getOutputStream();     

    FileInputStream fileInputStream = new FileInputStream(fileName);
    byte[] buffer = new byte[sk.getSendBufferSize()];
    int bytesRead = 0;

    while((bytesRead = fileInputStream.read(buffer))>0)
    {
        output.write(buffer,0,bytesRead);
    }

    output.close();
    fileInputStream.close();
}

}

client:

public class AndroidProtokolActivity extends Activity {

private File directory;

XmlSerializer serializer = Xml.newSerializer();
StringWriter writer=new StringWriter();;

Socket sk;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    directory = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "protocol");
    directory.mkdirs();
}

public void fun(View view)
{
    Log.i("======", "fun==============");
    try
    {
        sk = new Socket("55.555.555.555", 5555);

        String registrationFile = createRegistrationXML(serializer);
        sendToServer(registrationFile,sk);
        getRegistrationXML();
    }
    catch(Exception e)
    {
        e.printStackTrace();
    }
}

public void sendToServer(String file, Socket sk) throws Exception
{
    Log.i("======", "sendToServer==============");
    OutputStream output = sk.getOutputStream();     

    String pathToOurFile = directory + File.separator + file;

    FileInputStream fileInputStream = new FileInputStream(pathToOurFile);
    byte[] buffer = new byte[sk.getSendBufferSize()];
    int bytesRead = 0;

    while((bytesRead = fileInputStream.read(buffer))>0)
    {
        output.write(buffer,0,bytesRead);
    }

    output.close();
    fileInputStream.close();
}

public File getRegistrationXML() throws Exception
{
    Log.i("======", "getRegistrationXML==============");
    File file=null;

    InputStream input = sk.getInputStream();

    file = new File(directory, "rejestracjaOdpowiedz.xml");
    FileOutputStream out = new FileOutputStream(file);

    byte[] buffer = new byte[sk.getReceiveBufferSize()];

    int bytesReceived = 0;

    while((bytesReceived = input.read(buffer))>0) {
        out.write(buffer,0,bytesReceived);
    }

    input.close();
    input = null;
    out.flush();
    out.close();
    out = null;
    System.gc();

    return file;
}
}

I cut from this code creating XML files functions. I get “java.net.SocketException: Socket is closed” on line “OutputStream output = sk.getOutputStream();” in function “sendToApp” on server side and “java.net.SocketException: Socket is closed” on line “InputStream input = sk.getInputStream();” in “getRegistrationXML” line in function “getRegistrationXML” on client side. I try to find out what is wrong but I dont have any idea. Do anyone of you know what is wront with this code? Thanks for any help.

EDIT:

This code show how I create XML file:

public String createRegistrationXML(XmlSerializer serializer) throws Exception
{
    Log.i("======", "createRegistrationXML==============");
    XmlSerializer serializer = Xml.newSerializer();
    writer = new StringWriter();
    serializer.setOutput(writer);

    serializer.startDocument("UTF-8", true);
        serializer.startTag("", XMLTag);
            serializer.startTag("", eventTag);
                serializer.text(REGISTRATIONEVENT);
            serializer.endTag("", eventTag);
        serializer.endTag("", XMLTag);
    serializer.endDocument();

    File outputFile = new File(directory, "file.xml");
    FileOutputStream fos = new FileOutputStream(outputFile);
    OutputStreamWriter osw = new OutputStreamWriter(fos); 
    osw.write(writer.toString());
    osw.flush();
    osw.close();

    return "file.xml";
}

Answer 1

Try not to close the socket’s input and output stream individually. Just close the socket when all is done.