Socket实现简单的上传下载

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

//客户端
public class Client {
  public static void main(String[] args) throws Exception, IOException {
    System.out.println("================客户端==============");
    Socket socket = new Socket(InetAddress.getLocalHost(), 8888);
    //获取读取文件的输入流
    BufferedInputStream bis = new BufferedInputStream(new FileInputStream("D:\\q.txt"));
    //输出信息到服务端的输出流
    BufferedOutputStream bos = new BufferedOutputStream(socket.getOutputStream());
    byte [] b = new byte[1024];
    int len = 0;
    //边读边写
    while((len=bis.read(b))!=-1){
      bos.write(b, 0, len);
      bos.flush();
    }
    //在不关闭socket的条件下关闭输出流
    socket.shutdownOutput();
    //获取服务端反馈消息的输入流
    DataInputStream dis = new DataInputStream(socket.getInputStream());
    String mess = dis.readUTF();
    System.out.println(mess);
  }
}

服务端

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
  public static void main(String[] args) throws Exception {
    System.out.println("================服务端==============");
    ServerSocket ss = new ServerSocket(8888);
    Socket socket = ss.accept();
    //读取客户端发送的数据
    BufferedInputStream buf = new BufferedInputStream(socket.getInputStream());
    //将客户端发送的数据读取到本地
    BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("D:\\a.txt"));
    byte[] b = new byte[1024];
    int len = 0;
    //边读边写
    while ((len = buf.read(b)) != -1) {
      bos.write(b,0,len);
      bos.flush();
    }
    System.out.println("写出完毕");
    //发送消息到客户端
    DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
    dos.writeUTF("上传成功");
    dos.flush();
    dos.close();
    bos.close();
    buf.close();
  }
}