Java简单实现UDP和TCP的示例

//服务端public class TcpServer { public static void main(String[] args) throws IOException {  ServerSocket serverSocket = new ServerSocket(8886); // 建立服务端，ip为本机ip,端口为8886  Socket accept = serverSocket.accept(); // 监听客户端的连接，一旦有客户端连接，则会返回客户端对应的accept    InputStream in = accept.getInputStream(); //获取到客户端的输出流  byte b[] = new byte[1024];  int len = in.read(b);  System.out.println("接受到客户端数据,返回数据"+new String(b,0,len));     OutputStream out = accept.getOutputStream(); // 给客户端发送消息  out.write("服务端已经接受".getBytes());    serverSocket.close(); }}// 客户端public class TcpClient { public static void main(String[] args) throws IOException {  Socket socket = new Socket("127.0.0.1", 8886); // 通过Socket来建立和服务端的连接  OutputStream out = socket.getOutputStream(); // 获取输出流（客户端输出流即向服务端输出信息）  out.write("hello tcp Server".getBytes()); // 输出信息    InputStream in = socket.getInputStream(); // 接受服务端的消息  byte b[] = new byte[1024];  int len = in.read(b);  System.out.println("接受到服务器消息 ： "+new String(b,0,len)); // 输出  out.write("返回的的数据已经收到 ".getBytes()); // 向服务器返回消息  socket.close(); }}

// server public static void main(String[] args) throws IOException {  ServerSocket serverSocket = new ServerSocket(8886); // 建立服务端，ip为本机ip,端口为8886  int i=4;  while(i>2){   Socket accept = serverSocket.accept(); // 监听客户端的连接，一旦有客户端连接，则会返回客户端对应的accept      ServerThread st = new ServerThread(accept); // 启动线程   Thread th = new Thread(st);   th.start();  }  serverSocket.close(); }// threadpublic class ServerThread implements Runnable { private Socket accept; public ServerThread(Socket s) {  this.accept = s; } public void run(){  InputStream in;  try {   in = accept.getInputStream();   byte b[] = new byte[1024];   int len = in.read(b);   System.out.println("接受到客户端数据,返回数据" + new String(b, 0, len));   OutputStream out = accept.getOutputStream(); // 给客户端发送消息   out.write("服务端已经接受".getBytes());  } catch (IOException e) {   e.printStackTrace();  }  }}

// 服务端public class Server { public static void main(String[] args) throws IOException {  ServerSocket serverSocket = new ServerSocket(5555);  Socket ss = serverSocket.accept();    BufferedInputStream br = new BufferedInputStream(ss.getInputStream());  BufferedOutputStream bw = new BufferedOutputStream(new FileOutputStream("copy.jpg")); // 写出文件流    byte b[] = new byte[1024];  int len = 0;   while ((len = br.read(b)) != -1) { // 写出文件   bw.write(b, 0, len);   bw.flush(); // 别忘了刷新，要不然最后一块缓冲区字符串会缺失  }  BufferedWriter bw2 = new BufferedWriter(new OutputStreamWriter(ss.getOutputStream())); // 输出  bw2.write("图片传输成功");  bw2.flush();    bw.close();  ss.close(); }}// 客户端public class Client { public static void main(String[] args) throws UnknownHostException, IOException {  Socket socket = new Socket("127.0.0.1", 5555);  BufferedInputStream in = new BufferedInputStream(new FileInputStream("c.jpg"));  BufferedOutputStream out = new BufferedOutputStream(socket.getOutputStream());  byte b[] = new byte[1024];  int len = 0;  while ((len = in.read(b)) != -1) {   out.write(b, 0, len);   out.flush(); // 刷新缓冲区 要不然最后一块缓冲区字符串会缺失  }    socket.shutdownOutput(); // 关闭流以后Server段才会接收道结束字符结束接受  BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));  String line;  while ((line = br.readLine()) != null) {   System.out.println(line);  }    in.close();  socket.close(); }}

// 发送端public class SendDemo { public static void main(String[] args) throws IOException {  DatagramSocket ds = new DatagramSocket(); // 此类表示用来发送和接收数据报包的套接字。  BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); // 键盘输入  String line = null;  while ((line = br.readLine()) != null) {   byte[] bytes = line.getBytes();   DatagramPacket dp = new DatagramPacket(bytes, bytes.length, InetAddress.getByName("127.0.0.1"), 10005); // 数据包对象   ds.send(dp);   if ("886".equals(line)) { // 当输入886时结束发送    break;   }  }  ds.close(); }}// 接收端public class ReciveDemo { public static void main(String[] args) throws IOException {  DatagramSocket ds = new DatagramSocket(10005); // 建立服务端  byte bytes[] = new byte[1024];  DatagramPacket dp = new DatagramPacket(bytes, bytes.length); // 建立数据包对象  while (true) {   ds.receive(dp); // 接受数据包   byte[] data = dp.getData(); // 获取数据   String str = new String(data, 0, dp.getLength());   if ("886".equals(str)) {    break;   }   System.out.println(str);  }  ds.close(); }}