服务器端

package top.ltyzqhh.Net;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class TCPServiceDemo02 {
    public static void main(String[] args) throws Exception {
        //1.创建一个端口
        ServerSocket serverSocket = new ServerSocket(9000);
        //2.监听客户端的连接
        Socket socket = serverSocket.accept();//阻塞式监听,会一直等待客户端连接
        //3.获取输入流
        InputStream is = socket.getInputStream();
        //4.文件输出
        FileOutputStream fos = new FileOutputStream(new File("receive.png"));

        byte[] buffer = new byte[1024];
        int len;
        while((len=is.read(buffer))!=-1)
        {
            fos.write(buffer,0,len);
        }

        //通知客户端接收完毕了
        OutputStream os = socket.getOutputStream();
        os.write("我接受完毕了,你可以断开了".getBytes());

        //5.关闭资源
        fos.close();
        is.close();
        socket.close();
        serverSocket.close();

    }
}

客户端

package top.ltyzqhh.Net;

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

public class TCPCilentDemo02 {
    public static void main(String[] args) throws Exception {
        //创建一个soket连接
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
        //2.创建一个输出流
        OutputStream os = socket.getOutputStream();
        //3.文件流
        FileInputStream fileis = new FileInputStream(new File("readdead.png"));
        //4.写出文件
        byte[] buffer = new byte[1024];
        int len;
        while ((len=fileis.read(buffer))!=-1)
        {
            os.write(buffer,0,len);
        }
        //通知服务器, 我已经结束了
        socket.shutdownOutput();//我已经传完了

        //确定服务器接收完毕,才能够断开连接
        InputStream inputStream = socket.getInputStream();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        byte[] buffer2 = new byte[2014];
        int len2;
        while ((len2=inputStream.read(buffer2))!=-1)
        {
            baos.write(buffer2,0,len2);
        }
        System.out.println(baos.toString());

        //5.关闭资源
        baos.close();
        inputStream.close();
        fileis.close();
        os.close();
        socket.close();

    }
}