Java网络编程入门——基于TCP协议的简单C/S控制台登陆

前言

TCP和UDP的区别是开发的时候经常会遇到的问题，TCP是面向连接的协议，可靠，但是效率比UDP低，开销也大，适合文件传输、远程登录，HTTP协议也是基于TCP协议的，一切为了完整性和可靠性。UDP适合即时聊天，没有保证，但是即使出现了错误，重新传输的代价也不高。

在登陆系统中，是否登陆成功，是需要返回一个反馈的，所以采用TCP比较合适。

效果

这里设定了账号为oushile，密码为123，否则登陆失败

客户端：

服务端：

代码

Server.java:

package TCP;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket server=new ServerSocket(8888);
        Socket socket = server.accept();
        System.out.println("Connected!");
        DataInputStream dataInputStream = new DataInputStream(socket.getInputStream());
        String data=dataInputStream.readUTF();
        String[] split = data.split("&");
        for (String array:split){
            System.out.println(array);
        }
        DataOutputStream dataOutputStream = new DataOutputStream(socket.getOutputStream());

        if(split[0].equals("oushile")&&split[1].equals("123")){
            dataOutputStream.writeUTF("Successfully!");
            dataOutputStream.flush();
        }else{
            dataOutputStream.writeUTF("Failed,please check your messages");
            dataOutputStream.flush();
        }

        dataInputStream.close();
        server.close();

    }
}

Client.java

package TCP;

import java.io.*;
import java.net.Socket;

public class Client {
    public static void main(String[] args) throws IOException {
        Socket client=new Socket("localhost",8888);
        DataOutputStream dataOutputStream = new DataOutputStream(client.getOutputStream());
        System.out.println("请输入用户名");
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        String username=bufferedReader.readLine();
        System.out.println("Please input password");
        bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        String password = bufferedReader.readLine();

        dataOutputStream.writeUTF(username+"&"+password);
        dataOutputStream.flush();

        DataInputStream dataInputStream = new DataInputStream(client.getInputStream());
        System.out.println(dataInputStream.readUTF());

        dataOutputStream.close();
        client.close();


    }
}