即TCP协议下阻塞式传输
客户端：
@SuppressWarnings("resource")
Socket socket = new Socket("127.0.0.1", 8989);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter out = new PrintWriter(socket.getOutputStream(),true);
out.println("hello");
服务端：
ServerSocket ss = new ServerSocket(8989);
ss.setSoTimeout(10000);
Socket socket = ss.accept();
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String info = br.readLine();
System.out.println("Server receive info: " + info);
代码缺点：
服务端不能同时接收多个连接请求。
