Wifi局域網的Socket通訊（只能一對一的鏈接的狀況）

服務端：

  

import android.content.Context;
import android.net.wifi.WifiManager;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * Created by Zzm_Pc on 2016/12/28.
 */

public class StartingServerUtils {
    private InputStream input;
    private NewServerThread newServerThread;
    private Handler wifiHandler;
    private WifiAcceptThread acceptThread;
    private WifiServerThread serverThread;
    private WifiManager wifiManager;
    private ServerSocket wifiServerSocket;
    private Socket wifiSocket;
    private Context me;

    public StartingServerUtils(Context me, Handler handler) {
        this.me = me;
        this.wifiHandler = handler;
    }

    //accept connect
    private class WifiServerThread extends Thread {
        @Override
        public void run() {
            super.run();
            Log.i("information","WifiServerThread~~");
            try {
                wifiServerSocket = new ServerSocket(1099);
                wifiSocket = wifiServerSocket.accept();
                if (wifiSocket != null) {
                    input = wifiSocket.getInputStream();
                    Log.i("information", "鏈接成功~~");
                    wifiServerSocket.close();
                    acceptThread.start();
                    newServerThread.start();
                }
            } catch (IOException e) {
                Log.i("information", e.toString());
            }
        }
    }

    //turn string_ip method
    private String getStringIp(int ip) {
        return (ip & 0xFF) + "." +
                ((ip >> 8) & 0xFF) + "." +
                ((ip >> 16) & 0xFF) + "." +
                (ip >> 24 & 0xFF);
    }

    //accept information thread
    private class WifiAcceptThread extends Thread {
        private boolean is=true;
        @Override
        public void run() {
            super.run();
            Log.i("information","wifiAccept~~");
            if (input != null) {
                while (is) {
                    Log.i("information","讀取~~");
                    byte[] bytes = new byte[1024];
                    int length = 0;
                    try {
                        if (input!=null && (length = input.read(bytes)) != -1) {
                            Message msg = new Message();
                            msg.obj = new String(bytes, 0, length);
                            wifiHandler.sendMessage(msg);
                        }
                    } catch (IOException e) {
                        is=false;
                        Log.i("information", "讀取異常~~");
                    }
                }
            }

        }
    }

    //開啓服務的方法
    public void startServer() {
        wifiManager = (WifiManager) me.getSystemService(Context.WIFI_SERVICE);
        while (!wifiManager.isWifiEnabled()) {
            wifiManager.setWifiEnabled(true);
            Toast.makeText(me, "請開wifi~~", Toast.LENGTH_SHORT).show();
        }
        String ip = getStringIp(wifiManager.getConnectionInfo().getIpAddress());
        //展現ip
        //
        newServerThread = new NewServerThread();
        acceptThread = new WifiAcceptThread();
        serverThread = new WifiServerThread();
        serverThread.start();
    }

    //是否斷開鏈接，斷開則從新開啓服務
    private class NewServerThread extends Thread {
        private boolean is = true;

        @Override
        public void run() {
            super.run();
            Log.i("information","NewServerThread~~");
            while (is) {
                try {
                    wifiSocket.sendUrgentData(9);
                } catch (IOException e) {
                    Log.i("information", "斷開鏈接了~~");
                    is = false;
                    serverThread.interrupt();
                    acceptThread.interrupt();
                    wifiServerSocket = null;
                    try {
                        wifiSocket.close();
                        input.close();
                    } catch (IOException e1) {
                        Log.i("information", "Socket關閉失敗~");
                    }
                    input = null;
                    wifiSocket = null;
                    wifiManager = null;
                    startServer();
                }
            }
            Log.i("information","將會從新開啓服務~~");
        }
    }
}

客戶端：

public class ConnectServerUtils {
    public static String ip = "192.168.1.89";
    private AppCompatActivity me;
    private WifiManager wifiManager;
    private OutputStream output;
    static Socket wifiSocket;
    public ConnectServerUtils(AppCompatActivity me) {
        this.me = me;
    }

    private class WifiConnectThread extends Thread {

        @Override
        public void run() {
            super.run();
            try {
                wifiSocket = new Socket(ip, 1099);
                output = wifiSocket.getOutputStream();
                if (output != null) {
                    showToast("控制鏈接成功~~");
                } else {
                    showToast("控制鏈接失敗~請重試！");
                }
            } catch (IOException e) {
                Log.i("information", e.toString());
            }
        }
    }

    private void showToast(final String toastInformation) {
        me.runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(me, toastInformation, Toast.LENGTH_SHORT).show();
            }
        });
    }

    public OutputStream startConnectServer() {
        wifiManager = (WifiManager) me.getSystemService(Context.WIFI_SERVICE);
        if (!wifiManager.isWifiEnabled()) {
            Toast.makeText(me, "請開啓wifi~~~~", Toast.LENGTH_SHORT).show();
            wifiManager.setWifiEnabled(true);
        }
        Log.i("information", getStringIp(wifiManager.getConnectionInfo().getIpAddress()));
        new WifiConnectThread().start();
        SystemClock.sleep(500);
        return output;
    }

    //turn string_ip method
    private String getStringIp(int ip) {
        return (ip & 0xFF) + "." +
                ((ip >> 8) & 0xFF) + "." +
                ((ip >> 16) & 0xFF) + "." +
                (ip >> 24 & 0xFF);
    }
}

  最後記得要關閉：

@Override
protected void onDestroy() {
    super.onDestroy();
    try {
        ConnectServerUtils.wifiSocket.close();
    } catch (IOException e) {
        Log.i("information", e.toString());
    }
    ConnectServerUtils.wifiSocket = null;
}

否則按返回鍵的時候，再次鏈接，服務端會拒絕你的鏈接，只要加上以上代碼就好了。