Java网络编程：Socket 通信：文件上传

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

/**
 * @program: FirstDemo
 * @description: javaScoket网络编程：文件上传下载
 * @author: GuoTong
 * @create: 2020-08-25 18:05
 **/
public class ImageSocketServer {
    //服务端
    public static void main(String[] args) {
        System.out.println("文件上传服务端.....");
        //服务端
        ServerSocket serverSocket = null;
        Socket socket = null;
        BufferedInputStream inputStream = null;
        BufferedOutputStream outputStream = null;
        try {
            //1.创建服务端
            serverSocket = new ServerSocket(6666);
            //2.建立连接
            socket = serverSocket.accept();
            //通过接收客户端数据，输入流的方式
            inputStream = new BufferedInputStream(socket.getInputStream());
            //创建输出流保存到本地
            outputStream = new BufferedOutputStream(new FileOutputStream("copy.jpg"));
            //读数据
            byte[] bytes = new byte[1024 * 8];
            int len;
            while ((len = inputStream.read(bytes)) != -1) {
                outputStream.write(bytes, 0, len);
            }
            System.out.println("文件上传复制完毕");


        } catch (IOException e) {

            e.printStackTrace();

        } finally {
            try {
                if (outputStream != null) {
                    outputStream.close();
                }
                if (inputStream != null) {
                    inputStream.close();
                }
                if (socket != null) {
                    socket.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }
}
class ImageSocketClient{
    //客户端
    public static void main(String[] args) {
        Socket socket=null;
        BufferedInputStream inputStream = null;
        BufferedOutputStream outputStream = null;
        try {
            socket=new Socket(InetAddress.getByName("127.0.0.1"),6666);
            // 创建输入流,读取本地文件
            inputStream = new BufferedInputStream(new FileInputStream("./src/a123.jpg"));
            //传递文件给服务器
            outputStream = new BufferedOutputStream(socket.getOutputStream());
            //.写数据
            byte[] bytes = new byte[1024 * 8];
            int len;
            while ((len=inputStream.read(bytes))!=-1){
                outputStream.write(bytes,0,len);
                outputStream.flush();//清空
            }
            System.out.println("文件发送完毕。。。");

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (outputStream!=null)
                    outputStream.close();
                if (inputStream!=null)
                    inputStream.close();
                if (socket!=null)
                    socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

优化：回写实现，循环接收的问题

public class FileUpload_Server {
    public static void main(String[] args) throws IOException {
        System.out.println("服务器 启动.....  ");
        // 1. 创建服务端ServerSocket
        ServerSocket serverSocket = new ServerSocket(6666);
        // 2. 循环接收,建立连接
        while (true) {
            Socket accept = serverSocket.accept();
              /*
              3. socket对象交给子线程处理,进行读写操作
               Runnable接口中,只有一个run方法,使用lambda表达式简化格式
            */
            new Thread(new Runnable {
                try (
                    //3.1 获取输入流对象
                    BufferedInputStream bis = new BufferedInputStream(accept.getInputStream());
                    //3.2 创建输出流对象, 保存到本地 .
                    FileOutputStream fis = new FileOutputStream(System.currentTimeMillis() + ".jpg");
                    BufferedOutputStream bos = new BufferedOutputStream(fis);
                ) {
                    // 3.3 读写数据
                    byte[] b = new byte[1024 * 8];
                    int len;
                    while ((len = bis.read(b)) != -1) {
                        bos.write(b, 0, len);
                    }

                    // 4.=======信息回写===========================
                    System.out.println("back ........");
                    OutputStream out = accept.getOutputStream();
                    out.write("上传成功".getBytes());
                    out.close();
                    //================================

                    //5. 关闭 资源
                    bos.close();
                    bis.close();
                    accept.close();
                    System.out.println("文件上传已保存");
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }).start();
        }
    }
}

public class FileUpload_Client {
    public static void main(String[] args) throws IOException {
        // 1.创建流对象
        // 1.1 创建输入流,读取本地文件
        BufferedInputStream bis = new BufferedInputStream(new FileInputStream("test.jpg"));
        // 1.2 创建输出流,写到服务端
        Socket socket = new Socket("localhost", 6666);
        BufferedOutputStream bos = new BufferedOutputStream(socket.getOutputStream());

        //2.写出数据.
        byte[] b  = new byte[1024 * 8 ];
        int len ;
        while (( len  = bis.read(b))!=-1) {
            bos.write(b, 0, len);
        }
          // 关闭输出流,通知服务端,写出数据完毕
        socket.shutdownOutput();
        System.out.println("文件发送完毕");
        // 3. =====解析回写============
        InputStream in = socket.getInputStream();
        byte[] back = new byte[20];
        in.read(back);
        System.out.println(new String(back));
        in.close();
        // ============================

        // 4.释放资源
        socket.close();
        bis.close();
    }
}