java - 文件传输——Java套接字编程

Question

我有以下服务器和客户端代码。客户端尝试将大小为 2000B 的文件(例如“testprgm.txt”)传输到服务器，并将其保存为“Test.txt”。问题是我可以在服务器和客户端上看到字节传输，但是当我在运行这些代码后看到 Test.txt 文件的大小时，它是零。

服务器程序:

import java.io.*;
import java.net.*;

public class ServerTest {

    public static void main(String[] args) {
        System.out.println("**********Server Program**************");
        int byteRead = 0;
        try {
            ServerSocket serverSocket = new ServerSocket(9999);
            if (!serverSocket.isBound())
                System.out.println("Sever Socket not Bounded...");
            else
                System.out.println("Server Socket bounded to Port : " + serverSocket.getLocalPort());

            Socket clientSocket = serverSocket.accept();
            if (!clientSocket.isConnected())
                System.out.println("Client Socket not Connected...");
            else
                System.out.println("Client Socket Connected : " + clientSocket.getInetAddress());

            while (true) {
                InputStream in = clientSocket.getInputStream();

                OutputStream os = new FileOutputStream("<DESTINATION PATH>/Test.txt");
                byte[] byteArray = new byte[100];

                while ((byteRead = in .read(byteArray, 0, byteArray.length)) != -1) {
                    os.write(byteArray, 0, byteRead);
                    System.out.println("No. of Bytes Received : " + byteRead);
                }
                synchronized(os) {
                    os.wait(100);
                }
                os.close();
                serverSocket.close();
                //System.out.println("File Received...");
            }

        } catch (Exception e) {
            System.out.println("Server Exception : " + e.getMessage());
            e.printStackTrace();
        }
    }

}

客户端程序:

import java.io.*;
import java.net.*;

public class Clientprgm {

public static void main(String[] args)
{
    Socket socket;
    try
    {
        socket = new Socket("SERVER IP ADDRESS>", 9999);            
        if(!socket.isConnected())
            System.out.println("Socket Connection Not established");
        else
            System.out.println("Socket Connection established : "+socket.getInetAddress());

        File myfile = new File("<SOURCE PATH>/testprgm.txt");       //local file path.


        if(!myfile.exists())
            System.out.println("File Not Existing.");
        else
            System.out.println("File Existing.");

        byte[] byteArray = new byte[1024];

        FileInputStream fis = new FileInputStream(myfile);
        BufferedInputStream bis = new BufferedInputStream(fis);
        OutputStream os = socket.getOutputStream();
        int trxBytes =0;
        while((trxBytes = bis.read(byteArray, 0, byteArray.length)) !=-1)
        {           
        os.write(byteArray, 0, byteArray.length);
        System.out.println("Transfering bytes : "+trxBytes );
        }
        os.flush();
        bis.close();
        socket.close();

        System.out.println("File Transfered...");
    }
    catch(Exception e)
    {
        System.out.println("Client Exception : "+e.getMessage());
    }       
}
}

Answer 1

我会使用 NIO 进行文件传输，它更短、更高效。这是客户端:

    try (SocketChannel sc = SocketChannel.open(new InetSocketAddress(
            hostaddress, 9999));
            FileChannel fc = new FileInputStream("test").getChannel()) {
        fc.transferTo(0, fc.size(), sc);
    }
    System.out.println("File Transfered...");

服务器端:

    ServerSocketChannel ss = ServerSocketChannel.open();
    ss.bind(new InetSocketAddress("localhost", 9999));
    try (SocketChannel sc = ss.accept();
            FileChannel fc = new FileOutputStream("test").getChannel()) {
        fc.transferFrom(sc, 0, Long.MAX_VALUE);
    }