通信协议：传输码率，代码结构，传输控制…..TCP面向连接，稳定三次握手，四次挥手UDP 面向无连接，不稳定客户端、服务端：没有明确的界限
客户端InetAddress serverIP = InetAddress.getByName("127.0.0.1");int port = 9999;Socket socket = new Socket(serverIP,port);创建一个socket连接OutputStream os = socket.getOutputStream();发送消息 IO流服务器建立服务的端口 ServerSocket等待用户的链接 accept接收用的消息
eg：文件上传客户端public class Demo1 { public static void main(String[] args) throws IOException { BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream("C:\\Users\\张孛\\Desktop\\1许巍 - 曾经的你.mp3")); Socket socket = new Socket("127.0.0.1",5555); OutputStream outputStream = socket.getOutputStream(); byte[] bytes = new byte[1024]; int len=0; while ((len=inputStream.read(bytes))!=-1){ outputStream.write(bytes,0,len); } socket.shutdownOutput(); System.out.println("11111111111111"); InputStream inputStream1 = socket.getInputStream(); byte[] bytes1 = new byte[1024]; inputStream1.read(bytes1); System.out.println(new String(bytes1)); socket.close(); }}服务器public class Demo2 { public static void main(String[] args) throws IOException { ServerSocket serverSocket = new ServerSocket(5555); while (true){ Socket socket = serverSocket.accept(); InputStream inputStream = socket.getInputStream(); BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(new FileOutputStream(System.currentTimeMillis()+""+new Random().nextInt(100)+".mp3")); byte[] bytes = new byte[1024]; int len=0; while ((len=inputStream.read(bytes))!=-1){ bufferedOutputStream.write(bytes,0,len); } OutputStream outputStream = socket.getOutputStream(); outputStream.write("已收到信息".getBytes()); socket.close(); }}}
UDP不需要连接服务器
public class UdpClientDemo01 { public static void main(String[] args) throws Exception { DatagramSocket socket = new DatagramSocket(); String msg = "发送给服务器"; InetAddress localhost = InetAddress.getByName("localhost"); int port = 5555; DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length, localhost, port); socket.send(packet); socket.close(); }}
接收端
public class UdpServerDemo01 { public static void main(String[] args) throws Exception { DatagramSocket socket = new DatagramSocket(5555); byte[] buffer = new byte[1024]; DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length); socket.receive(packet); System.out.println(packet.getAddress().getHostAddress()); System.out.println(new String(packet.getData(),0,packet.getLength())); socket.close(); }}