Java Socket Tcp

package com.apesblog.day_27;

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;
import java.net.UnknownHostException;

import org.junit.jupiter.api.Test;

public class TcpTest {
    @Test
    public void client() {
        Socket socket = null;
        OutputStream outputStream = null;
        try {
            socket = new Socket(InetAddress.getByName("127.0.0.1"), 4399);
            outputStream = socket.getOutputStream();
            outputStream.write("您好，tcp".getBytes());
        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                if (outputStream == null)
                    outputStream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                if (socket == null)
                    socket.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }

    @Test
    public void server() {
        ServerSocket serverSocket = null;
        Socket accept = null;
        InputStream inputStream = null;
        ByteArrayOutputStream byteArrayOutputStream = null;
        try {
            serverSocket = new ServerSocket(4399);
            accept = serverSocket.accept();
            inputStream = accept.getInputStream();
            byteArrayOutputStream = new ByteArrayOutputStream();
            byte[] buffer = new byte[5];
            int len;
            while ((len = inputStream.read(buffer)) != -1) {
                byteArrayOutputStream.write(buffer, 0, len);
            }
            System.out.println(byteArrayOutputStream.toString());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            byteArrayOutputStream.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                if (byteArrayOutputStream == null)
                    byteArrayOutputStream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();

            }
            try {
                if (inputStream == null)
                    inputStream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                if (accept == null)
                    accept.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                if (serverSocket == null)
                    serverSocket.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }
}