TCP基本步骤

分析：
1.TCP协议基于请求-响应模式
2.在网络通讯中，第一次主动发起通讯的程序被称作客户端程序
3.第一次通讯中等待连接的程序被称作服务器端程序
4.利用IO流实现数据的传输

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

public class LoginServer {
    public static void main(String[] args) throws IOException {
        ServerSocket server = new ServerSocket(8888);
        Socket accept = server.accept();
        String uname = "";
        String upwd = "";
        DataInputStream dis = new DataInputStream(accept.getInputStream());
        String s = dis.readUTF();
        String[] dataArray = s.split("&");
        for (String data : dataArray) {
            String[] userInfo = data.split("=");
            if (userInfo[0].equals("uname")) {
                uname = userInfo[1];
            }
            if (userInfo[0].equals("upwd")) {
                upwd = userInfo[1];
            }
        }
        DataOutputStream dos = new DataOutputStream(accept.getOutputStream());
        if (uname.equals("katsuna") && upwd.equals("kotonoha")) {
            dos.writeUTF("成功");
        } else {
            dos.writeUTF("失败");
        }
        dos.flush();
        dos.close();
        dis.close();
        accept.close();
        server.close();
    }
}

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

/**
 * 模拟登陆
 */
public class LoginClient {
    public static void main(String[] args) throws IOException {
        BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("请输入用户名");
        String uname = console.readLine();
        System.out.println("请输入密码");
        String upwd = console.readLine();
        Socket client = new Socket("127.0.0.1", 8888);
        DataOutputStream dos = new DataOutputStream(client.getOutputStream());
        dos.writeUTF("uanme=" + uname + "&upwd=" + upwd);
        dos.flush();
        DataInputStream dis = new DataInputStream(client.getInputStream());
        String s = dis.readUTF();
        System.out.println(s);
        dis.close();
        dos.close();
        client.close();
    }
}