socket编程

通过socket在本机上通信：

TCPClient.java

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;
import java.net.UnknownHostException;




public class TCPClient {

    public static void main(String[] args) throws UnknownHostException, IOException {
        String sentence;            //存储用户输入的字符串
        String modifiedsentence;    //存储经过服务器修改的字符串
        BufferedReader inFromUser=new BufferedReader(new InputStreamReader(System.in));//创建一个从标准输入流输入的对象
        Socket clientSocket=new Socket("127.0.0.1",9999);//建立一个socket对象.127..0.0.1表示本机
        DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());//创建一个经由tcp的输出对象
        BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));//创建一个经由tcp的输入对象
        sentence=inFromUser.readLine();//读取用户的输入
        outToServer.writeBytes(sentence+'\n');//将用户数据传入到服务器
        modifiedsentence=inFromServer.readLine();//将修改后的数据接收回来
        System.out.println(modifiedsentence);//在标准输出上输出字符串
        clientSocket.close();
    }

}

TCPServer.java

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;


public class TCPServer {

    public static void main(String[] args) throws IOException {
    String clientSentence;
    String capitalizedSentence;
    @SuppressWarnings("resource")
    ServerSocket welcomeSocket=new ServerSocket(9999);
    while(true){
        Socket connectionSocket=welcomeSocket.accept();
        BufferedReader inFromClient=new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
        DataOutputStream outToClient=new DataOutputStream(connectionSocket.getOutputStream());
        clientSentence=inFromClient.readLine();
        capitalizedSentence=clientSentence.toUpperCase()+'\n';
        outToClient.writeBytes(capitalizedSentence);
  
        
    }
    }

}