java实现Socket通信之单线程服务

import java.net.*;
import java.io.*;
 
public class EchoServer {
  public static void main(String[] args)throws IOException {
    if (args.length != 1) {
      System.out.println("用法：EchoServer <端口号>");
      return ;
    }
 
    // 监听客户程序的连接请求
    ServerSocket listenSocket = new ServerSocket(Integer.parseInt(args[0]));
    System.out.println("服务程序正在监听端口" + args[0]);
    Socket socket = listenSocket.accept();
    // 从与客户程序的新建连接获取输入流和输出流
    PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
    BufferedReader in = new BufferedReader(new InputStreamReader
      (socket.getInputStream()));
    // 从客户端读取数据，并写回数据的加工结果
    String message;
    while ((message = in.readLine()) != null) {
      System.out.println("收到请求：" + message);
      out.println(message.toUpperCase());
    }
 
    // 关闭连接
    out.close();
    in.close();
    socket.close();
    listenSocket.close();
  }
}

import java.net.*;
import java.io.*;
 
public class EchoClient {
  public static void main(String[] args)throws Exception {
    if (args.length != 2) {
      System.out.println("用法：EchoClient <主机名> <端口号>");
      return ;
    }
 
    // 建立连接并打开相关联的输入流和输出流
    Socket socket = new Socket(args[0], Integer.parseInt(args[1]));
    System.out.println("当前socket信息：" + socket);
    PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
    BufferedReader in = new BufferedReader(new InputStreamReader
      (socket.getInputStream()));
 
    // 将控制台输入的字符串发送给服务端，并显示从服务端获取的处理结果
    BufferedReader stdIn = new BufferedReader(new InputStreamReader
      (System.in));
    String userInput;
    while ((userInput = stdIn.readLine()) != null) {
      out.println(userInput);
      System.out.println("返回：" + in.readLine());
    }
    stdIn.close();
    // 关闭连接
    out.close();
    in.close();
    socket.close();
  }
}