UDP：
无连接协议
udp协议发送数据，用的是数据报包的形式。(64KB以内)
发送端：
1.定义发送的datagramsocket对象，发送端可以不用定义端口
2.定义封装数据包datagrampacket
3.发送数据包
4.关闭资源
//InetAddress.getByName("192.168.3.255")必须是统一的网段
public class UdpSendThread implements Runnable {
DatagramSocket ds;
byte[] buf;
public UdpSendThread(DatagramSocket ds) {
this.ds = ds;
}
public UdpSendThread(DatagramSocket ds, String str) {
this.ds = ds;
this.buf = str.getBytes();
}
@Override
public void run() {
String brStr;
try {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in, "utf-8"));
while ((brStr = br.readLine()) != null) {
if(brStr.startsWith("@")){
}
DatagramPacket dp = new DatagramPacket(brStr.getBytes(), brStr.getBytes().length,
InetAddress.getByName("192.168.3.255"), 9000);
ds.send(dp);
if (brStr.equals("over")) {
break;
}
}
//br.close();
ds.close();
} catch (UnknownHostException | UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
接收端：
1、建立DatagramSocket对象
2、定义一个空的数据包
3、接受数据包
4、解析数据包
5、关闭资源
public class UdpRececiveThread extends Thread {
DatagramSocket ds;
public UdpRececiveThread(DatagramSocket ds) {
this.ds = ds;
}
@Override
public void run() {
while(true){
byte[] buf = new byte[1024*1024];
DatagramPacket dp = new DatagramPacket(buf, buf.length);
try {
ds.receive(dp);
String ip = dp.getAddress().getHostAddress();
String content = new String(dp.getData(),0,dp.getLength());
if(content.equals("over")){
System.out.println(ip+"退出");
}
System.out.println(ip+":"+content);
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
测试类：
public static void main(String[] args) throws SocketException {
DatagramSocket sendDs = new DatagramSocket();
DatagramSocket reDs = new DatagramSocket(9000);
new Thread(new UdpSendThread(sendDs)).start();;
new UdpRececiveThread(reDs).start();
}