TCP transmission

Server side

package TCPUDP;

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

public class TcpServerDemo01 {
    
    public static void main(String[] args) throws Exception {
    
        //1, Create a port 
        ServerSocket serverSocket = new ServerSocket(9000);
        //2, Listen for client connections 
        Socket socket = serverSocket.accept();// Blocking monitoring , First class client connection 

        //3, Get input stream 
        InputStream is = socket.getInputStream();

        //4, file move 
        FileOutputStream fos = new FileOutputStream(new File("receive"));
        byte[] buffer = new byte[1024];
        int len;
        while((len=is.read(buffer))!=-1){
    
            fos.write(buffer,0,len);
        }

        // notice · The client has received 
        OutputStream os = socket.getOutputStream();
        os.write(" I'm finished , You can disconnect ".getBytes());
        // close resource 
        fos.close();
        is.close();
        socket.close();
        serverSocket.close();
    }
}

client

Yes bug The picture has never been found , Has given up , The code is not wrong

package TCPUDP;

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

public class TcpClientDemo02 {
    
    public static void main(String[] args) throws IOException {
    
        //1, Create a Socket Connect 
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);

        //2, Create an output stream 
        OutputStream os=socket.getOutputStream();
        //3, File stream 
        FileInputStream fis = new FileInputStream(new File("fj.jpg"));

        //4, Write a document 
        byte[] buffer = new byte[1024];
        int len;
        while((len=fis.read())!=-1){
    
            os.write(buffer,0,len);
        }

        // Notification server , I've finished 
        socket.shutdownOutput();// I've already transmitted it 
        // Make sure the server has received it , To disconnect ( String pipeline flow )
        InputStream inputStream=socket.getInputStream();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer2 = new byte[1024];
        int len2;
        while((len2=inputStream.read(buffer2))!=-1){
    
            baos.write(buffer2,0,len2);
        }
        // close resource 
        baos.close();
        inputStream.close();
        fis.close();
        os.close();
        socket.close();
    }

}