java - W/System.err : java.net.SocketException:套接字已关闭

Question

我有一个问题。我关闭此应用程序收到错误。虽然socket服务器还没有被访问过。能怎么解决呢？套接字服务器是 fragment 。能影响这个吗？

    W/System.err: java.net.SocketException: Socket closed
W/System.err:     at java.net.PlainSocketImpl.socketAccept(Native Method)
W/System.err:     at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:389)
W/System.err:     at java.net.ServerSocket.implAccept(ServerSocket.java:531)
W/System.err:     at java.net.ServerSocket.accept(ServerSocket.java:499)
W/System.err:     at ro.vrt.videoplayerstreaming.Torrent_remote$SocketServerThread.run(Torrent_remote.java:92)
W/System.err:     at java.lang.Thread.run(Thread.java:761)

              --------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: Thread-9
                  Process: ro.vrt.videoplayerstreaming, PID: 2652
                  java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.app.FragmentActivity.runOnUiThread(java.lang.Runnable)' on a null object reference
                      at ro.vrt.videoplayerstreaming.Torrent_remote$SocketServerThread.run(Torrent_remote.java:134)
                      at java.lang.Thread.run(Thread.java:761)
D/FA: Application backgrounded. Logging engagement
D/FA: Logging event (FE): _e, Bundle[{_o=auto, _et=560890}]
V/FA: Using local app measurement service
V/FA: Local AppMeasurementService is starting up
V/FA: Bound to IMeasurementService interface
V/FA: Connected to service
V/FA: Processing queued up service tasks: 1
V/FA: Logging event: origin=auto,name=_e,params=Bundle[{_o=auto, _et=560890}]
D/FA: Unable to get advertising id: com.google.android.gms.common.GooglePlayServicesNotAvailableException: com.google.android.gms.measurement.internal.zzt.zzly(Unknown Source)
V/FA: Saving event, name, data size: _e, 30
V/FA: Event recorded: Event{appId='ro.vrt.videoplayerstreaming', name='_e', params=Bundle[{_o=auto, _et=560890}]}
V/FA: Upload scheduled in approximately ms: 3095074
V/FA: Background event processing time, ms: 20
V/FA: Inactivity, disconnecting from AppMeasurementService
V/FA: onUnbind called for intent. action: com.google.android.gms.measurement.START
V/FA: Local AppMeasurementService is shutting down

代码:

    mport android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.TextView;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;

public class Torrent_remote extends Fragment {

    TextView info, infoip, msg;
    String message = "";
    ServerSocket serverSocket;


    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.activity_torrent_remote, container, false);

        info = (TextView) v.findViewById(R.id.info);
        infoip = (TextView) v.findViewById(R.id.infoip);
        msg = (TextView) v.findViewById(R.id.msg);

        infoip.setText(getIpAddress());

        Thread socketServerThread = new Thread(new SocketServerThread());
        socketServerThread.start();


        return v;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        if (serverSocket != null) {
            try {
                serverSocket.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }

    private class SocketServerThread extends Thread {

        static final int SocketServerPORT = 8080;
        int count = 0;

        @Override
        public void run() {
            Socket socket = null;
            DataInputStream dataInputStream = null;
            DataOutputStream dataOutputStream = null;

            try {
                serverSocket = new ServerSocket(SocketServerPORT);
                getActivity().runOnUiThread(new Runnable() {

                    @Override
                    public void run() {
                        info.setText("I'm waiting here: "
                                + serverSocket.getLocalPort());
                    }
                });

                while (true) {
                    socket = serverSocket.accept();
                    dataInputStream = new DataInputStream(
                            socket.getInputStream());
                    dataOutputStream = new DataOutputStream(
                            socket.getOutputStream());

                    String messageFromClient = "";

                    //If no message sent from client, this code will block the program
                    messageFromClient = dataInputStream.readUTF();

                    count++;
                    message += "#" + count + " from " + socket.getInetAddress()
                            + ":" + socket.getPort() + "\n"
                            + "Msg from client: " + messageFromClient + "\n";

                    getActivity().runOnUiThread(new Runnable() {

                        @Override
                        public void run() {
                            msg.setText(message);
                        }
                    });

                    String msgReply = "Hello from VRT Player Android Tv, msg nr #" + count;
                    dataOutputStream.writeUTF(msgReply);

                    String url = messageFromClient;
                    //Put the value
                    Torrent_fragment ldf = new Torrent_fragment();
                    Bundle args = new Bundle();
                    args.putString("url", url);
                    ldf.setArguments(args);
                    getFragmentManager().beginTransaction().replace(R.id.frame, ldf).commit();



                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                final String errMsg = e.toString();
                getActivity().runOnUiThread(new Runnable() {

                    @Override
                    public void run() {
                        msg.setText(errMsg);
                    }
                });

            } finally {
                if (socket != null) {
                    try {
                        socket.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }

                if (dataInputStream != null) {
                    try {
                        dataInputStream.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }

                if (dataOutputStream != null) {
                    try {
                        dataOutputStream.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        }

    }

    private String getIpAddress() {
        String ip = "";
        try {
            Enumeration<NetworkInterface> enumNetworkInterfaces = NetworkInterface
                    .getNetworkInterfaces();
            while (enumNetworkInterfaces.hasMoreElements()) {
                NetworkInterface networkInterface = enumNetworkInterfaces
                        .nextElement();
                Enumeration<InetAddress> enumInetAddress = networkInterface
                        .getInetAddresses();
                while (enumInetAddress.hasMoreElements()) {
                    InetAddress inetAddress = enumInetAddress.nextElement();

                    if (inetAddress.isSiteLocalAddress()) {
                        ip += "SiteLocalAddress: "
                                + inetAddress.getHostAddress() + "\n";
                    }

                }

            }

        } catch (SocketException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            ip += "Something Wrong! " + e.toString() + "\n";
        }

        return ip;
    }
}

并不总是出现此错误。谢谢

Answer 1

您应该在关闭套接字之前检查套接字是否已关闭(使用serverSocket.isClosed())。因此，将您的onDestroy代码更改为:

@Override
public void onDestroy() {
    super.onDestroy();

    if (serverSocket != null && !serverSocket.isClosed()) {
        try {
            serverSocket.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

更新

看起来问题出在这个线程上:

SocketServerThread

此线程在 fragment 内运行，因此请确保在使用 socket 时调用 socket.close(); 之前关闭此线程。在此Thread内接受()，因此当您关闭onDestory方法内的Socket时会导致错误，然后它尝试来自 Thread 的 socket.accept()，因为它仍在运行。