Android之Socket的基于UDP传输

来源：互联网发布：2017大数据企业50强编辑：程序博客网时间：2024/05/16 15:45

接收方创建步骤：

1. 创建一个DatagramSocket对象，并指定监听的端口号

DatagramSocket socket = new DatagramSocket (4567);

2. 创建一个byte数组用于接收

byte data[] = new byte[1024];

3. 创建一个空的DatagramPackage对象

DatagramPackage package = new DatagramPackage(data , data.length);

4. 使用receive方法接收发送方所发送的数据,同时这也是一个阻塞的方法

socket.receive(package);

5. 得到发送过来的数据

new String(package.getData() , package.getOffset() , package.getLength());

发送方创建步骤：

1. 创建一个DatagramSocket对象

DatagramSocket socket = new DatagramSocket (4567);

2. 创建一个 InetAddress ，相当于是地址

InetAddress serverAddress = InetAddress.getByName("想要发送到的那个IP地址");

3. 这是随意发送一个数据

String str = "hello";

4. 转为byte类型

byte data[] = str.getBytes();

5. 创建一个DatagramPacket 对象，并指定要讲这个数据包发送到网络当中的哪个地址，以及端口号

DatagramPacket package = new DatagramPacket (data , data.length , serverAddress , 4567);

6. 调用DatagramSocket对象的send方法发送数据

socket . send(package);

http://www.cnblogs.com/lee0oo0/archive/2012/04/04/2431907.html

一、有的手机不能直接接收UDP包，可能是手机厂商在定制Rom的时候把这个功能给关掉了。

1、可先在oncreate()方法里面实例化一个WifiManager.MulticastLock 对象lock；具体如下：

WifiManager manager = (WifiManager) this                .getSystemService(Context.WIFI_SERVICE);WifiManager.MulticastLock lock= manager.createMulticastLock("test wifi");

2、在调用广播发送、接收报文之前先调用lock.acquire()方法；

3、用完之后及时调用lock.release()释放资源，否决多次调用lock.acquire()方法，程序可能会崩，详情请见

Caused by: java.lang.UnsupportedOperationException: Exceeded maximum number of wifi locks

注；记得在配置文件里面添加如下权限：

<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />

经过这样处理后，多数手机都能正常发送接收到广播报文。

本小点转载自Android手机接收不到UDP报文

二、在UDP通信中，android端发送UDP广播包没有问题。至于接收的话，有时候不能接收到包。

在UDP通信中，android端发送UDP广播包没有问题。至于接收的话，有时候不能接收到包。但是如果UDP包中指定了目标主机的地址的话，那么android端就能正常接收。

下面上一段代码，大家可用这段代码进行测试。

1、在一个Service里面，我们创建一个线程

public void onCreate() {//用于创建线程        WifiManager manager = (WifiManager) this                .getSystemService(Context.WIFI_SERVICE);        udphelper = new UdpHelper(manager);                //传递WifiManager对象，以便在UDPHelper类里面使用MulticastLock        udphelper.addObserver(MsgReceiveService.this);        tReceived = new Thread(udphelper);        tReceived.start();        super.onCreate();    }

2、弄一个UDP帮助类，这个类主要用于发送和接收数据

package com.example.com.ihome.bang.util;import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.MulticastSocket;import java.net.SocketException;import java.net.UnknownHostException;import java.util.Observable;import com.example.com.ihome.bang.tool.SendThread;import android.net.wifi.WifiManager;import android.util.Log;/** *  * UdpHelper帮助类 *  * @author 陈喆榕 *  */public class UdpHelper  implements Runnable {    public    Boolean IsThreadDisable = false;//指示监听线程是否终止    private static WifiManager.MulticastLock lock;    InetAddress mInetAddress;    public UdpHelper(WifiManager manager) {         this.lock= manager.createMulticastLock("UDPwifi");     }    public void StartListen()  {        // UDP服务器监听的端口        Integer port = 8903;        // 接收的字节大小，客户端发送的数据不能超过这个大小        byte[] message = new byte[100];        try {            // 建立Socket连接            DatagramSocket datagramSocket = new DatagramSocket(port);            datagramSocket.setBroadcast(true);            DatagramPacket datagramPacket = new DatagramPacket(message,                    message.length);            try {                while (!IsThreadDisable) {                    // 准备接收数据                    Log.d("UDP Demo", "准备接受");                     this.lock.acquire();                                         datagramSocket.receive(datagramPacket);                    String strMsg=new String(datagramPacket.getData()).trim();                    Log.d("UDP Demo", datagramPacket.getAddress()                            .getHostAddress().toString()                            + ":" +strMsg );this.lock.release();                }            } catch (IOException e) {//IOException                e.printStackTrace();            }        } catch (SocketException e) {            e.printStackTrace();        }    }    public static void send(String message) {        message = (message == null ? "Hello IdeasAndroid!" : message);        int server_port = 8904;        Log.d("UDP Demo", "UDP发送数据:"+message);        DatagramSocket s = null;        try {            s = new DatagramSocket();        } catch (SocketException e) {            e.printStackTrace();        }        InetAddress local = null;        try {            local = InetAddress.getByName("255.255.255.255");        } catch (UnknownHostException e) {            e.printStackTrace();        }        int msg_length = message.length();        byte[] messageByte = message.getBytes();        DatagramPacket p = new DatagramPacket(messageByte, msg_length, local,                server_port);        try {            s.send(p);            s.close();                    } catch (IOException e) {            e.printStackTrace();        }    }    @Override    public void run() {            StartListen();    }}

作者：kissazi2
出处：http://www.cnblogs.com/kissazi2/
本文版权归作者所有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。

最后，添加个人的实例：

package com.example.android.helloactivity;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import com.example.andriod.udp.UDPClient;
import com.example.andriod.udp.UDPServer;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainAct extends Activity {
   EditText msg_et = null;
   Button send_bt = null;
   TextView info_tv = null;
   private static final String TAG ="MainAct";
   private UDPClient client;
   private String sendInfo;

   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.udp_test);
       msg_et = (EditText) findViewById(R.id.edit_msg);
       send_bt = (Button) findViewById(R.id.send_bt);
       info_tv = (TextView) findViewById(R.id.receive_msg);
       info_tv.setText("source");
       // 开启服务器
       ExecutorService exec = Executors.newCachedThreadPool();
       UDPServer server = new UDPServer();
       exec.execute(server);
       // 发送消息
       send_bt.setOnClickListener(new OnClickListener() {
           @Override
           public void onClick(View v) {

               myThread1 thread = new myThread1("22");
               new Thread(thread).start();

           }
       });
   }

   final Handler mHander = new Handler() {

       public void handleMessage(Message msg) {
           // TODO Auto-generated method stub
           //super.handleMessage(msg);
           info_tv.setText(sendInfo);

           Log.d(TAG, "client.send()=");
       }
   };

   class myThread1 implements Runnable {

       private String threadName;

       public myThread1(String name) {
           this.threadName = name;
       }

       public void run() {
           Log.d(TAG, "MyThread execu"+msg_et.getText().toString());
           client = new UDPClient(msg_et.getText().toString());
           sendInfo=client.send();

           Message msg = mHander.obtainMessage();
           msg.arg1=1;
           mHander.sendMessage(msg);
           Log.d(TAG, "client.send()=");
       }
   }
}

package com.example.andriod.udp;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

import android.util.Log;

public class UDPServer implements Runnable {
   private static final int PORT = 6000;
   private byte[] msg = new byte[2048];
   private boolean life = true;

   public UDPServer() {
   }

   public boolean isLife() {
       return life;
   }

   public void setLife(boolean life) {
       this.life = life;
   }

   @Override
   public void run() {
       DatagramSocket dSocket = null;
       DatagramPacket dPacket = new DatagramPacket(msg, msg.length);
       try {
           dSocket = new DatagramSocket(PORT);
           while (life) {
               try {
                   dSocket.receive(dPacket);
                   Log.d("tian msg sever received",
                           new String(dPacket.getData(), dPacket.getOffset(),
                                   dPacket.getLength())
                                   + "dPacket.getLength()="
                                   + dPacket.getLength());
               } catch (IOException e) {
                   e.printStackTrace();
               }
           }
       } catch (SocketException e) {
           e.printStackTrace();
       }
   }
}

package com.example.andriod.udp;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;

import android.util.Log;

public class UDPClient {
   private static final int SERVER_PORT = 6000;
   private DatagramSocket dSocket = null;
   private String msg;

   public UDPClient(String msg) {
       super();
       this.msg = msg;
   }

   public String send() {
       StringBuilder sb = new StringBuilder();
       InetAddress local = null;
       try {
           local = InetAddress.getByName("localhost"); // 本机测试
           sb.append("已找到服务器,连接中...").append("/n");
       } catch (UnknownHostException e) {
           sb.append("未找到服务器.").append("/n");
           e.printStackTrace();
       }
       try {
           dSocket = new DatagramSocket(); // 注意此处要先在配置文件里设置权限,否则会抛权限不足的异常
           sb.append("正在连接服务器...").append("/n");
       } catch (SocketException e) {
           e.printStackTrace();
           sb.append("服务器连接失败.").append("/n");
       }
       int msg_len = msg == null ? 0 : msg.length();
       DatagramPacket dPacket = new DatagramPacket(msg.getBytes(), msg_len,
               local, SERVER_PORT);
       try {
           dSocket.send(dPacket);
           Log.d("tian", "msg=="+msg+"dpackage="+dPacket.getData()+"dPacket.leng="+dPacket.getLength());
           sb.append("消息发送成功!").append("/n");
       } catch (IOException e) {
           e.printStackTrace();
           sb.append("消息发送失败.").append("/n");
       }
       dSocket.close();
       return sb.toString();
   }
}

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