由于实际工作中UDP使用得比较少，所以这里只给出了BIO中UDP的使用。不过也基本满足了UDP的使用入门了，可以实现局域网搜索（起码对我目前的工作来说是够用了）。至于UDP用于音视频数据传输，得读者自己寻找，或者等我了解之后，更新。
BIO_UDP_Searcher package self; import java.io.IOException; import java.net.*; /** * @Description： * @Author: jarry */ public class UDPSearcher { public static void main(String[] args) throws IOException { System.out.println("UDPSearcher started."); // 构建UDP的Socket（由于是searcher，即数据的率先发送者，所以可以不用指定port，用于监听） DatagramSocket datagramSocket = new DatagramSocket(); // 构建请求消息的实体（包含目标ip及port） String requestMsg = "just a joke."; byte[] requestBytes = requestMsg.getBytes(); DatagramPacket requestPacket = new DatagramPacket(requestBytes, requestBytes.length); requestPacket.setAddress(Inet4Address.getLocalHost()); requestPacket.setPort(20000); // 发送请求数据 System.out.println("UDPSearcher has send msg."); datagramSocket.send(requestPacket); // 接收回送数据 byte[] buf = new byte[512]; DatagramPacket receivePacket = new DatagramPacket(buf,buf.length); datagramSocket.receive(receivePacket); String sourceIp = receivePacket.getAddress().getHostAddress(); int sourcePort = receivePacket.getPort(); int dataLength = receivePacket.getLength(); String receiveData = new String(receivePacket.getData(),0,receivePacket.getData().length); // 显示接收到的数据 System.out.println("UDPSearcher has received data with source:"+sourceIp+":"+sourcePort+" with length "+dataLength+". data:"+receiveData); // 由于是demo，所以不用循环，就此结束 System.out.println("UDPSearcher finished."); datagramSocket.close(); } } BIO_UDP_Provider package self; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException; /** * @Description： * @Author: jarry */ public class UDPProvider { public static void main(String[] args) throws IOException { System.out.println("UDPProvider started."); // 新建DatagramSocekt，并设定在本机20000端口监听，并接收消息 DatagramSocket datagramSocket = new DatagramSocket(20000); // 新建DatagramPacket实体 byte[] buf = new byte[512]; DatagramPacket datagramPacket = new DatagramPacket(buf,buf.length); // 接收数据 datagramSocket.receive(datagramPacket); // 处理接受到的数据 String sourceIp = datagramPacket.getAddress().getHostAddress(); int sourcePort = datagramPacket.getPort(); String data = new String(datagramPacket.getData(),0,datagramPacket.getLength()); // 显示接收到的数据 System.out.println("UDPProvider has received data with source:"+sourceIp+":"+sourcePort+" with length "+data.length()+". data:"+data); // 准备发送回送数据 String responseData = "UDPProvider has received data with length:"+data.length(); byte[] responseBytes = responseData.getBytes(); // 构建回送数据实体（别玩了，设置目标ip与port） DatagramPacket responsePacket = new DatagramPacket(responseBytes, responseBytes.length ,datagramPacket.getAddress(),datagramPacket.getPort()); // 发送回送数据 System.out.println("UDPProvider has sended data."); datagramSocket.send(responsePacket); // 由于是demo，所以不用循环，就此结束 System.out.println("UDPProvider finished."); datagramSocket.close(); } }