MulticastSocket是对等的关系,也就是他们通过IP多点组播保留的地址来相互接收在这个组的Socket发送的消息
我写了一个例子,MultiSocketB是一个service,用于先接收再发送,MultiSocketA用于先发送再接收,完成这一动作后退出
记得要加使用网络的权限
- <uses-permission android:name="android.permission.INTERNET" />
先看MultiSocketA
- <?xml version="1.0" encoding="utf-8"?>
- <manifest xmlns:android="http://schemas.android.com/apk/res/android"
- package="com.example.multicastsocketsend"
- android:versionCode="1"
- android:versionName="1.0" >
- <uses-permission android:name="android.permission.INTERNET" />
- <uses-sdk
- android:minSdkVersion="8"
- android:targetSdkVersion="17" />
- <application
- android:allowBackup="true"
- android:icon="@drawable/ic_launcher"
- android:label="@string/app_name"
- android:theme="@style/AppTheme" >
- <activity
- android:name="com.example.multicastsocketsend.MultiSocketA"
- android:label="@string/app_name" >
- <intent-filter>
- <action android:name="android.intent.action.MAIN" />
- <category android:name="android.intent.category.LAUNCHER" />
- </intent-filter>
- </activity>
- </application>
- </manifest>
- package com.example.multicastsocketsend;
- import java.io.IOException;
- import java.net.DatagramPacket;
- import java.net.InetAddress;
- import java.net.MulticastSocket;
- import android.app.Activity;
- import android.os.Bundle;
- import android.os.Handler;
- import android.os.HandlerThread;
- import android.util.Log;
- /**
- * @author lijinwei
- * 本应用用于实现IP多点广播
- * 若要使用多点广播时,则需要让一个数据报标有一组目标主机地址,当数据报发出后,整个组的所有主机都能收到该数据报。
- * IP多点广播(或多点发送)实现了将单一信息发送到多个接收者的广播,其思想是设置一组特殊网络地址作为多点广播地址,每一个多点广播地址都被看做一个组,
- * 当客户端需要发送、接收广播信息时,加入到该组即可。
- */
- public class MultiSocketA extends Activity {
- protected static final String TAG = "MultiSocketA";
- private Handler mHandler;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- //通过Handler启动线程
- HandlerThread handlerThread = new HandlerThread("MultiSocketA");
- handlerThread.start();
- mHandler = new Handler(handlerThread.getLooper());
- mHandler.post(mRunnable);
- }
- private Runnable mRunnable = new Runnable() {
- public void run() {
- Log.v(TAG, "run...");
- try {
- sendMultiBroadcast();
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- private void sendMultiBroadcast() throws IOException {
- Log.v(TAG, "sendMultiBroadcast...");
- /*
- * 实现多点广播时,MulticastSocket类是实现这一功能的关键,当MulticastSocket把一个DatagramPacket发送到多点广播IP地址,
- * 该数据报将被自动广播到加入该地址的所有MulticastSocket。MulticastSocket类既可以将数据报发送到多点广播地址,
- * 也可以接收其他主机的广播信息
- */
- MulticastSocket socket = new MulticastSocket(8600);
- //IP协议为多点广播提供了这批特殊的IP地址,这些IP地址的范围是224.0.0.0至239.255.255.255
- InetAddress address = InetAddress.getByName("224.0.0.1");
- /*
- * 创建一个MulticastSocket对象后,还需要将该MulticastSocket加入到指定的多点广播地址,
- * MulticastSocket使用jionGroup()方法来加入指定组;使用leaveGroup()方法脱离一个组。
- */
- socket.joinGroup(address);
- /*
- * 在某些系统中,可能有多个网络接口。这可能会对多点广播带来问题,这时候程序需要在一个指定的网络接口上监听,
- * 通过调用setInterface可选择MulticastSocket所使用的网络接口;
- * 也可以使用getInterface方法查询MulticastSocket监听的网络接口。
- */
- //socket.setInterface(address);
- DatagramPacket packet;
- //发送数据包
- Log.v(TAG, "send packet");
- byte[] buf = "Hello I am MultiSocketA".getBytes();
- packet = new DatagramPacket(buf, buf.length, address, 8601);
- socket.send(packet);
- //接收数据
- Log.v(TAG, "receiver packet");
- byte[] rev = new byte[512];
- packet = new DatagramPacket(rev, rev.length);
- socket.receive(packet);
- Log.v(TAG, "get data = " + new String(packet.getData()).trim()); //不加trim,则会打印出512个byte,后面是乱码
- //退出组播
- socket.leaveGroup(address);
- socket.close();
- }
- };
- }
再看MultiSocketB
- <?xml version="1.0" encoding="utf-8"?>
- <manifest xmlns:android="http://schemas.android.com/apk/res/android"
- package="com.example.multicastsocketreceiver"
- android:versionCode="1"
- android:versionName="1.0" >
- <uses-permission android:name="android.permission.INTERNET" />
- <uses-sdk
- android:minSdkVersion="8"
- android:targetSdkVersion="17" />
- <application
- android:allowBackup="true"
- android:icon="@drawable/ic_launcher"
- android:label="@string/app_name"
- android:theme="@style/AppTheme" >
- <activity
- android:name="com.example.multicastsocketreceiver.MainActivity"
- android:label="@string/app_name" >
- <intent-filter>
- <action android:name="android.intent.action.MAIN" />
- <category android:name="android.intent.category.LAUNCHER" />
- </intent-filter>
- </activity>
- <service android:name=".MultiSocketB" />
- </application>
- </manifest>
- package com.example.multicastsocketreceiver;
- import android.os.Bundle;
- import android.app.Activity;
- import android.content.Intent;
- public class MainActivity extends Activity {
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- Intent intent = new Intent();
- intent.setClass(this, MultiSocketB.class);
- this.startService(intent);
- }
- }
- package com.example.multicastsocketreceiver;
- import java.io.IOException;
- import java.net.DatagramPacket;
- import java.net.InetAddress;
- import java.net.MulticastSocket;
- import android.app.Service;
- import android.content.Intent;
- import android.os.Handler;
- import android.os.HandlerThread;
- import android.os.IBinder;
- import android.util.Log;
- public class MultiSocketB extends Service {
- protected static final String TAG = "MultiSocketB";
- private Handler mHandler;
- @Override
- public IBinder onBind(Intent intent) {
- return null;
- }
- @Override
- public void onCreate() {
- super.onCreate();
- Log.v(TAG, "onCreate");
- // 通过Handler启动线程
- HandlerThread handlerThread = new HandlerThread("MultiSocketB");
- handlerThread.start();
- mHandler = new Handler(handlerThread.getLooper());
- mHandler.post(mRunnable);
- }
- private Runnable mRunnable = new Runnable() {
- public void run() {
- Log.v(TAG, "run...");
- try {
- receiveMultiBroadcast();
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- };
- protected void receiveMultiBroadcast() throws IOException {
- Log.v(TAG, "receiveMultiBroadcast...");
- MulticastSocket socket = new MulticastSocket(8601);
- InetAddress address = InetAddress.getByName("224.0.0.1");
- socket.joinGroup(address);
- DatagramPacket packet;
- // 接收数据
- Log.v(TAG, "receiver packet");
- byte[] rev = new byte[512];
- packet = new DatagramPacket(rev, rev.length);
- socket.receive(packet);
- String receiver = new String(packet.getData()).trim(); //不加trim,则会打印出512个byte,后面是乱码
- Log.v(TAG, "get data = " + receiver);
- //发送数据包
- Log.v(TAG, "send packet");
- String process_receiver = "I am MultiSocketB, I got " + receiver;
- byte[] buf = process_receiver.getBytes();
- packet = new DatagramPacket(buf, buf.length, address, 8600);
- socket.send(packet);
- //退出组播
- socket.leaveGroup(address);
- socket.close();
- }
- }