用Java模拟TCP网络编程

package com.stream;

import org.junit.Test;

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

public class Network2 {

    //客户端发送信息给服务端，服务端将数据显示在控制台上

    @Test
    public void client() {
        Socket socket = null;
        OutputStream outputStream = null;
        try {
            //对方的IP
            InetAddress ip = InetAddress.getByName("172.20.10.6");
            socket = new Socket(ip, 8187);

            outputStream = socket.getOutputStream();
            outputStream.write("你好我是客户端".getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
//            //关闭资源
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    @Test
    public void server() {
        ServerSocket serverSocket = null;
        Socket socket = null;
        InputStream inputStream = null;
        ByteArrayOutputStream byteArrayOutputStream = null;
        try {
            //1、创建服务器端的ServerSocket，指明自己的端口号
            serverSocket = new ServerSocket(8187);
            //2、接收来自客户端的socket
            socket = serverSocket.accept();
            //3、获取输入流
            inputStream = socket.getInputStream();

            //4、读取输入流中的数据
            byteArrayOutputStream = new ByteArrayOutputStream();
            byte[] buffer = new byte[20];
            int len;
            while ((len = inputStream.read(buffer)) != -1) {
                //将字节存储在数组中
                byteArrayOutputStream.write(buffer, 0, len);
            }
            //调用toString()
            System.out.println(byteArrayOutputStream.toString());
            System.out.println("收到了"+socket.getInetAddress().getHostAddress());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (byteArrayOutputStream != null) {
                try {
                    byteArrayOutputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (serverSocket != null) {
                try {
                    serverSocket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}