Question

以下是“TCP SERVER”代码，当任何客户端第一次连接代码运行得很好时，但是一旦客户端断开并再次连接TCP SERVER，客户端连接成功但无法发送数据。

如何检测客户端与服务器断开连接？

 import android.content.Context;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 import android.net.wifi.WifiManager;
 import android.os.AsyncTask;
 import android.os.CountDownTimer;
 import android.os.Handler;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.View;
 import android.util.Log;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;
 import android.widget.Toast;
 import java.io.BufferedReader;
 import java.io.InputStreamReader;
 import java.io.PrintWriter;
 import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.NetworkInterface;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.Enumeration;

 public class MainActivity extends AppCompatActivity {

     TextView tvStatus;
     EditText etPort, etMsg, etTransmit;
     Button btnListen, btnServerSend;
     Handler UIHandler;

     private int SERVERPORT1;
     private InetAddress addr;
     private ServerSocket serverSocket;
     private Socket clientSocket = null;
     private BufferedReader in;
     private PrintWriter out;

     //    public static final int SERVERPORT = 3000;
     private WifiManager wifiManager = null;
     private WifiManager.WifiLock lock = null;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         wifi();
         UIHandler = new Handler();
         tvStatus = (TextView) findViewById(R.id.tvStatus);

         etMsg = (EditText) findViewById(R.id.etMsg);
         etTransmit = (EditText) findViewById(R.id.etTransmit);
         etPort = (EditText) findViewById(R.id.etPort);

         btnListen = (Button) findViewById(R.id.btnListen);
         btnServerSend = (Button) findViewById(R.id.btnServerSend);
 //  ******************* Register controls end ******************************

         btnListen.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 new ServerClass().execute(etPort.getText().toString());
             }
         });
     }

     public String getLocalIpAddress() throws Exception {
         String resultIpv6 = "";
         String resultIpv4 = "";

         for (Enumeration en = NetworkInterface.getNetworkInterfaces();
              en.hasMoreElements(); ) {

             NetworkInterface intf = (NetworkInterface) en.nextElement();
             for (Enumeration enumIpAddr = intf.getInetAddresses();
                  enumIpAddr.hasMoreElements(); ) {

                 InetAddress inetAddress = (InetAddress) enumIpAddr.nextElement();
                 if (!inetAddress.isLoopbackAddress()) {
                     if (inetAddress instanceof Inet4Address) {
                         resultIpv4 = inetAddress.getHostAddress().toString();
                     } else if (inetAddress instanceof Inet6Address) {
                         resultIpv6 = inetAddress.getHostAddress().toString();
                     }
                 }
             }
         }
         return ((resultIpv4.length() > 0) ? resultIpv4 : resultIpv6);
     }

     private class ServerClass extends AsyncTask<String, Object, String> {
         private String input;

         @Override
         protected String doInBackground(String... params) {
        try {
            SERVERPORT1 = Integer.parseInt(params[0]);
            addr = InetAddress.getByName(getLocalIpAddress());
            serverSocket = new ServerSocket(SERVERPORT1, 0, addr);

            while (true) {
                clientSocket = serverSocket.accept();
                clientSocket.setTcpNoDelay(true);
                MainActivity.this.runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                    tvStatus.setText(clientSocket.getInetAddress().toString() + " Client connected");
                        Toast.makeText(MainActivity.this, "Server started...", Toast.LENGTH_SHORT).show();
                    }
                });
                in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
                out = new PrintWriter(clientSocket.getOutputStream(), true);
                if (!Thread.currentThread().isInterrupted()) {
                    input = in.readLine();
                    if (input != null) {
                        UIHandler.post(new updateUIThread1(input.toString()));
                        out.println("Received from client: " + input);
                    } else {
                        MainActivity.this.runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                new ServerClass().execute(etPort.getText().toString());
                            }
                        });
                    }
                }
            }


        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
     }

     private class updateUIThread1 implements Runnable {
         private String input = null;

         public updateUIThread1(String input) {
             this.input = input;
         }

         @Override
         public void run() {
             if (input.getBytes().length != 0) {
                 etMsg.append("\n" + input.toString());
                 Toast.makeText(MainActivity.this, "Answer: " + input, Toast.LENGTH_SHORT).show();
             }else {
                 Toast.makeText(MainActivity.this, "Empty", Toast.LENGTH_SHORT).show();
             }
         }
     }
 }

日志显示如下：

04-22 12:57:05.799 10857-10931/com.chat.admin.clientserver I/System.out: [CDS]shutdownInput in read
04-22 12:57:05.799 10857-10931/com.chat.admin.clientserver I/System.out: [CDS]shutdownInput in read
04-22 12:57:05.799 10857-10931/com.chat.admin.clientserver I/System.out: [CDS]shutdownInput in read
04-22 12:57:05.799 10857-10931/com.chat.admin.clientserver I/System.out: [CDS]shutdownInput in read
04-22 12:57:05.799 10857-10931/com.chat.admin.clientserver I/System.out: [CDS]shutdownInput in read

                                                                     read: unexpected EOF!

Answer 1

如果客户端断开连接，请不要创建新服务器。

相反，你应该有一个循环，这样你就可以再次调用.accept（）来等待新的客户端。

如何解决Tcp服务器中的错误

1 个答案: