使用TCP套接字编程

编程要求：

1. 一个客户机从其标准输入(键盘)读取一行字符，并通过其套接字将该行发送给服务器。
2. 服务器从其连接套接字读取一行字符。
3. 服务器将该行 转换成大写。
4. 服务器将修改后的行通过其连接套接字再回发给客户机。
5. 客户机从其套接字中读取修改后的行，然后将该行在其标准输出(监视器)上打印出来。

java代码：

package com.rjxy.socket;
import java.net.ServerSocket;
import java.net.Socket;
public class TCPServer {
	public static void main(String[] args)throws Exception {
		// TODO Auto-generated method stub
		ServerSocket welcomeSocket = new ServerSocket(8888);//服务器端开了一个应用进程，这个进程的端口号是8888
		while(true){
			Socket s = welcomeSocket.accept();
			//接收客户端发来的连接请求，如果没有客户端请求，则一直处于阻塞状态
			System.out.println("a client connected!");
			Client c = new Client(s);
			c.start();
		}
	}
}

package com.rjxy.socket;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
public class Client extends Thread{
	Socket s;
	DataInputStream dis;//输入流，用来读入数据
	DataOutputStream dos;//输出流，用来输出数据
	public Client(Socket s){
		this.s = s;
		try {
			dis = new DataInputStream(s.getInputStream());
			dos = new DataOutputStream(s.getOutputStream());
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	@Override
	public void run() {
		// TODO Auto-generated method stub
		while(true){
			String clientSentence;
			try {
				clientSentence = dis.readUTF();//读取字符串
				String capitalizadSentence = clientSentence.toUpperCase();//将小写字母转化为大写
				dos.writeUTF(capitalizadSentence);//
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
				System.out.println("a client disconnected");
			}
		}
	}
}

package com.rjxy.socket;

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.Socket;
public class TCPClient {
	public static void main(String[] args)throws Exception {
		// TODO Auto-generated method stub
		Socket s = new Socket("127.0.0.1",8888);
		//向服务端发出请求
		System.out.println("success");
		//System.out.println(sentence);
		DataOutputStream outToServer = new DataOutputStream(s.getOutputStream());
		DataInputStream inFromServer = new DataInputStream(s.getInputStream());
		BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
		while(true){
			String sentence = inFromUser.readLine();//从控制台读入数据
			outToServer.writeUTF(sentence);//将该字符串发送到服务端的输入流
			System.out.println("From Server:"+inFromServer.readUTF());
		}
	}
}