android：Udp广播/单播/组播的实现

udp，单播组播广播的讲解，很细致，可以学习一下

单播，组播(多播)，广播以及任播单播(unicast): 是指封包在计算机网络的传输中，目的地址为单一目标的一种传输方式。它是现今网络应用最为广泛，通常所使用的网络协议或服务大多采用单播传输，例如一切基于TCP的协议。组播(multicast): 也叫多播， 多点广播或群播。 指把信息同时传递给一组目的地址。它使用策略是最高效的，因为消息在每条网络链路上只需传递一次，而且只有在链路分叉的时候，消息才会被复制。广播(broadcahttps://colobu.com/2014/10/21/udp-and-unicast-multicast-broadcast-anycast/

package cn.titansys.xview_pptv;import androidx.appcompat.app.AppCompatActivity;import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;import com.yunze.udp.jh601a_message;import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.MulticastSocket;public class Main3Activity extends AppCompatActivity {//组播地址组播端口private static String MULTICAST_IP = "238.1.238.1";private static int MULTICAST_PORT = 5001;//广播地址，广播端口private static String BROADCAST_IP = "255.255.255.255";private static int BROADCAST_PORT = 8887;//单播端口，单播地址private String serverHost = "192.168.200.211";private static int UNICAST_PORT = 8888;private boolean isRuning = true;String mip = "238.1.238.1";int mport = 5001;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main3);onBroadcastReceive();onUnicastReceive();onMulticastSendReceive();}/*** 广播发送*/public void onBroadcastSend(View view) {new Thread(new Runnable() {@Overridepublic void run() {try {InetAddress inetAddress = InetAddress.getByName(BROADCAST_IP);DatagramSocket datagramSocketSend = new DatagramSocket();byte[] data = jh601a_message.message(mip,mport,"01","0000","8899aabb","ccdd");DatagramPacket datagramPacket = new DatagramPacket(data, data.length, inetAddress, BROADCAST_PORT);datagramSocketSend.send(datagramPacket);
// 发送设置为广播datagramSocketSend.setBroadcast(true);datagramSocketSend.close();} catch (Exception e) {e.printStackTrace();}}}).start();}/*** 广播接受*/public void onBroadcastReceive() {new Thread(new Runnable() {@Overridepublic void run() {try {
// 创建接收数据报套接字并将其绑定到本地主机上的指定端口DatagramSocket datagramSocket = new DatagramSocket(BROADCAST_PORT);while (isRuning) {byte[] buf = new byte[1024];final DatagramPacket datagramPacket = new DatagramPacket(buf, buf.length);datagramSocket.receive(datagramPacket);runOnUiThread(new Runnable() {@Overridepublic void run() {serverHost = datagramPacket.getAddress().getHostAddress();final String message = new String(datagramPacket.getData(), 0, datagramPacket.getLength())+ " from " + datagramPacket.getAddress().getHostAddress() + ":" + datagramPacket.getPort();Toast.makeText(Main3Activity.this, "广播接受=" + message, Toast.LENGTH_SHORT).show();}});Thread.sleep(1000);}} catch (Exception e) {e.printStackTrace();}}}).start();}/*** 单播发送*/public void onUnicastSend(View view) {new Thread(new Runnable() {@Overridepublic void run() {try {InetAddress inetAddress = InetAddress.getByName(serverHost);byte[] message = jh601a_message.message(mip,mport,"01","0000","8899aabb","ccdd");DatagramPacket datagramPacket = new DatagramPacket(message, message.length,inetAddress, UNICAST_PORT);DatagramSocket datagramSocket = new DatagramSocket();datagramSocket.send(datagramPacket);datagramSocket.close();} catch (Exception e) {e.printStackTrace();}}}).start();}/*** 单播接受*/public void onUnicastReceive() {new Thread(new Runnable() {@Overridepublic void run() {try {DatagramSocket server = new DatagramSocket(UNICAST_PORT);while (isRuning) {byte[] buf = new byte[1024];final DatagramPacket datagramPacket = new DatagramPacket(buf, buf.length);server.receive(datagramPacket);runOnUiThread(new Runnable() {@Overridepublic void run() {String receiveMsg = new String(datagramPacket.getData(), 0, datagramPacket.getLength())+ " from " + datagramPacket.getAddress().getHostAddress() + ":" + datagramPacket.getPort();Toast.makeText(Main3Activity.this, "单播接受=" + receiveMsg, Toast.LENGTH_SHORT).show();}});Thread.sleep(1000);}} catch (Exception e) {e.printStackTrace();}}}).start();}/*** 组播发送*/public void onMulticastSend(View view) {new Thread(new Runnable() {@Overridepublic void run() {try {
//IP组InetAddress inetAddress = InetAddress.getByName(MULTICAST_IP);
//组播监听端口MulticastSocket multicastSocket = new MulticastSocket(MULTICAST_PORT);multicastSocket.setTimeToLive(1);
//加入该组multicastSocket.joinGroup(inetAddress);
//将本机的IP（这里可以写动态获取的IP）地址放到数据包里，其实server端接收到数据包后也能获取到发包方的IP的byte[] data = jh601a_message.message(mip,mport,"01","0000","8899aabb","ccdd");DatagramPacket dataPacket = new DatagramPacket(data, data.length, inetAddress, MULTICAST_PORT);multicastSocket.send(dataPacket);multicastSocket.close();} catch (IOException e) {e.printStackTrace();}}}).start();}/*** 组播接受*/private void onMulticastSendReceive() {new Thread(new Runnable() {@Overridepublic void run() {try {InetAddress inetAddress = InetAddress.getByName(MULTICAST_IP);MulticastSocket multicastSocket = new MulticastSocket(MULTICAST_PORT);multicastSocket.joinGroup(inetAddress);byte buf[] = new byte[1024];DatagramPacket datagramPacket = new DatagramPacket(buf, buf.length, inetAddress, MULTICAST_PORT);while (isRuning) {multicastSocket.receive(datagramPacket);final String message = new String(buf, 0, datagramPacket.getLength());runOnUiThread(new Runnable() {@Overridepublic void run() {Toast.makeText(Main3Activity.this, "组播接受=" + message, Toast.LENGTH_SHORT).show();}});Thread.sleep(1000);}} catch (Exception e) {e.printStackTrace();}}}).start();}}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"tools:context=".Main3Activity"><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:onClick="onBroadcastSend"android:text="广播发送" /><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:onClick="onMulticastSend"android:text="组播发送" /><Buttonandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:onClick="onUnicastSend"android:text="单播发送" /></LinearLayout>