Java实现TCP/IP协议的收发数据（服务端）代码实例

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
  //监听端口
  private static final int PORT = 60020;

  public static void main(String[] args) throws IOException {
    ServerSocket serverSocket = null;
    Socket socket = null;
    try {
      //建立服务器的Socket，并设定一个监听的端口PORT
      serverSocket = new ServerSocket(PORT);
      //由于需要进行循环监听，因此获取消息的操作应放在一个while大循环中
      while(true){
         try {
          //建立跟客户端的连接
          socket = serverSocket.accept();
         } catch (Exception e) {
           System.out.println("建立与客户端的连接出现异常");
           e.printStackTrace();
         }
         ServerThread thread = new ServerThread(socket);
         thread.start();
      }
    } catch (Exception e) {
      System.out.println("端口被占用");
      e.printStackTrace();
    }    
    finally {
      serverSocket.close();
    }
  }
}

//服务端线程类
//继承Thread类的话，必须重写run方法，在run方法中定义需要执行的任务。
class ServerThread extends Thread {
  private Socket socket ;
  InputStream inputStream;
  OutputStream outputStream;
  
  public ServerThread(Socket socket){
    this.socket=socket;
  }
  public void run(){
    try {
      while (true){
        //接收客户端的消息并打印
        System.out.println(socket);
        inputStream=socket.getInputStream();
        byte[] bytes = new byte[1024];
        inputStream.read(bytes);
        String string = new String(bytes);
        System.out.println(string);  
        
        //向客户端发送消息
        outputStream = socket.getOutputStream();
        outputStream.write("OK".getBytes());
        System.out.println("OK");
        
      }
    } catch (Exception e) {
      System.out.println("客户端主动断开连接了");
      //e.printStackTrace();
    }
    //操作结束，关闭socket
    try{
      socket.close(); 
    }catch(IOException e){
      System.out.println("关闭连接出现异常");  
      e.printStackTrace();
    }
  }
}