客户端:

package inet;

import java.io.File;
import java.io.FileInputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class TcpClientDemo2 {

    public static void main(String[] args) throws Exception {
        //1.创建一个socket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.读取文件
        FileInputStream fis=new FileInputStream(new File("1.jpg"));
        //4.写出文件
        byte[] bytes=new byte[1024];
        int len=0;
        while((len=fis.read(bytes))!=-1){
            os.write(bytes,0,len);
        }

        //5.关闭资源
        fis.close();
        os.close();
        socket.close();


    }
}

服务端:

package inet;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class TcpServerDemo2 {
    public static void main(String[] args) throws IOException {
        //创建服务
        ServerSocket serverSocket=new ServerSocket(9000);
        //监听客户端连接
        Socket socket=serverSocket.accept();//阻塞式监听,会一直等待客户端连接
        //获取输入流
        InputStream is=socket.getInputStream();
        //文件输出
        FileOutputStream os=new FileOutputStream("E:\\2021.jpg");
        byte[] bytes=new byte[1024];
        int len=0;
        while((len=is.read(bytes))!=-1){
            os.write(bytes,0,len);
        }

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


    }
}

加上消息的传输后:

客户端:

package inet;

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

public class TcpClientDemo2 {

    public static void main(String[] args) throws Exception {
        //1.创建一个socket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.读取文件
        FileInputStream fis=new FileInputStream(new File("1.jpg"));
        //4.写出文件
        byte[] bytes=new byte[1024];
        int len=0;
        while((len=fis.read(bytes))!=-1){
            os.write(bytes,0,len);
        }

        //通知服务器我已经传输完毕
        socket.shutdownOutput();//我已经传输完了

        //确定服务器接收到了,才能断开连接
        InputStream inputStream=socket.getInputStream();
        ByteArrayOutputStream baos=new ByteArrayOutputStream();

        byte[] bytes2=new byte[1024];
        int len2=0;
        while((len2=inputStream.read(bytes2))!=-1){
            baos.write(bytes2,0,len2);
        }
        System.out.println(baos.toString());

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


    }
}

服务端:

package inet;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.StandardCharsets;

public class TcpServerDemo2 {
    public static void main(String[] args) throws IOException {
        //创建服务
        ServerSocket serverSocket=new ServerSocket(9000);
        //监听客户端连接
        Socket socket=serverSocket.accept();//阻塞式监听,会一直等待客户端连接
        //获取输入流
        InputStream is=socket.getInputStream();
        //文件输出
        FileOutputStream os=new FileOutputStream("E:\\2021.jpg");
        byte[] bytes=new byte[1024];
        int len=0;
        while((len=is.read(bytes))!=-1){
            os.write(bytes,0,len);
        }

        //通知客户端已接收完毕
        OutputStream outputStream=socket.getOutputStream();
        outputStream.write("我接收完毕了,你可以断开了".getBytes());

        //关闭资源
        outputStream.close();
        os.close();
        is.close();
        socket.close();
        serverSocket.close();


    }
}