udp，单播组播广播的讲解，很细致，可以学习一下
https://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;
@Override
protected 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() {
@Override
public 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() {
@Override
public 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() {
@Override
public 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() {
@Override
public 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() {
@Override
public 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() {
@Override
public 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() {
@Override
public 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() {
@Override
public 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() {
@Override
public 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">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onBroadcastSend"
android:text="广播发送" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onMulticastSend"
android:text="组播发送" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onUnicastSend"
android:text="单播发送" />
</LinearLayout>