Android获取局域网所有设备的ip地址



android 手机局域网扫描PC机；

利用android的ping命令扫描局域网内所有ip，
并对其进行socket通信



import java.io.DataInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.Socket;
import java.net.SocketException;
import java.util.Enumeration;
import org.apache.http.conn.util.InetAddressUtils;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;

public class NetTool {


  private int SERVERPORT = 8888 ;

  private String locAddress; //存储本机ip，例：本地ip ：192.168.1.

  private Runtime run = Runtime.getRuntime(); //获取当前运行环境，来执行ping，相当于windows的cmd

  private Process proc = null ;

  private String ping = "ping -c 1 -w 0.5 " ; //其中 -c 1为发送的次数，-w 表示发送后等待响应的时间

  private int j; //存放ip最后一位地址 0-255

  private Context ctx; //上下文

  public NetTool(Context ctx){
    this .ctx = ctx;
  }



  private Handler handler = new Handler(){

    public void dispatchMessage(Message msg) {
      switch (msg.what) {

      case 222 : // 服务器消息
        break ;

      case 333 : // 扫描完毕消息
        Toast.makeText(ctx, "扫描到主机：" +((String)msg.obj).substring( 6 ), Toast.LENGTH_LONG).show();

        break ;
      case 444 : //扫描失败
        Toast.makeText(ctx, (String)msg.obj, Toast.LENGTH_LONG).show();
        break ;
      }
    }

  };



  //向serversocket发送消息
  public String sendMsg(String ip,String msg) {

    String res = null ;
    Socket socket = null ;

    try {
      socket = new Socket(ip, SERVERPORT);
      //向服务器发送消息
      PrintWriter os = new PrintWriter(socket.getOutputStream());
      os.println(msg);
      os.flush(); // 刷新输出流，使Server马上收到该字符串

      //从服务器获取返回消息
      DataInputStream input = new DataInputStream(socket.getInputStream());
      res = input.readUTF();
      System.out.println( "server 返回信息：" + res);
      Message.obtain(handler, 222 , res).sendToTarget(); //发送服务器返回消息

    } catch (Exception unknownHost) {
      System.out.println( "You are trying to connect to an unknown host!" );
    } finally {
      // 4: Closing connection
      try {
        if (socket != null ) {
          socket.close();
        }
      } catch (IOException ioException) {
        ioException.printStackTrace();
      }
    }
    return res;
  }



  /**
   * 扫描局域网内ip，找到对应服务器
   */
  public void scan(){

    locAddress = getLocAddrIndex(); //获取本地ip前缀

    if (locAddress.equals( "" )){
      Toast.makeText(ctx, "扫描失败，请检查wifi网络" , Toast.LENGTH_LONG).show();
      return ;
    }

    for ( int i = 0 ; i < 256 ; i++) { //创建256个线程分别去ping

      j = i ;

      new Thread( new Runnable() {

        public void run() {

          String p = NetTool. this .ping + locAddress + NetTool. this .j ;

          String current_ip = locAddress+ NetTool. this .j;

          try {
            proc = run.exec(p);

            int result = proc.waitFor();
            if (result == 0 ) {
              System.out.println( "连接成功" + current_ip);
              // 向服务器发送验证信息
              String msg = sendMsg(current_ip, "scan" +getLocAddress()+ " ( " +android.os.Build.MODEL+ " ) " );

              //如果验证通过...
              if (msg != null ){
                if (msg.contains( "OK" )){
                  System.out.println( "服务器IP：" + msg.substring( 8 ,msg.length()));
                  Message.obtain(handler, 333 , msg.substring( 2 ,msg.length())).sendToTarget(); //返回扫描完毕消息
                }
              }
            } else {

            }
          } catch (IOException e1) {
            e1.printStackTrace();
          } catch (InterruptedException e2) {
            e2.printStackTrace();
          } finally {
            proc.destroy();
          }
        }
      }).start();

    }

  }


  //获取本地ip地址
  public String getLocAddress(){

    String ipaddress = "" ;

    try {
      Enumeration en = NetworkInterface.getNetworkInterfaces();
      // 遍历所用的网络接口
      while (en.hasMoreElements()) {
        NetworkInterface networks = en.nextElement();
        // 得到每一个网络接口绑定的所有ip
        Enumeration address = networks.getInetAddresses();
        // 遍历每一个接口绑定的所有ip
        while (address.hasMoreElements()) {
          InetAddress ip = address.nextElement();
          if (!ip.isLoopbackAddress()
              && InetAddressUtils.isIPv4Address(ip.getHostAddress())) {
            ipaddress = ip.getHostAddress();
          }
        }
      }
    } catch (SocketException e) {
      Log.e( "" , "获取本地ip地址失败" );
      e.printStackTrace();
    }

    System.out.println( "本机IP:" + ipaddress);

    return ipaddress;

  }

  //获取IP前缀
  public String getLocAddrIndex(){

    String str = getLocAddress();

    if (!str.equals( "" )){
      return str.substring( 0 ,str.lastIndexOf( "." )+ 1 );
    }

    return null ;
  }

  //获取本机设备名称
  public String getLocDeviceName() {

    return android.os.Build.MODEL;

  }


}