网络编程传输文件的java源代码

我可以回答这个问题。以下是一个简单的网络编程传输文件的 Java 源代码：

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

public class FileTransferClient {
public static void main(String[] args) {
String serverName = "localhost";
int port = 808;
String fileName = "test.txt";
try {
Socket clientSocket = new Socket(serverName, port);
OutputStream outToServer = clientSocket.getOutputStream();
DataOutputStream out = new DataOutputStream(outToServer);
out.writeUTF(fileName);
InputStream inFromServer = clientSocket.getInputStream();
DataInputStream in = new DataInputStream(inFromServer);
int fileSize = in.readInt();
byte[] fileBytes = new byte[fileSize];
in.readFully(fileBytes, , fileSize);
FileOutputStream fileOut = new FileOutputStream(fileName);
fileOut.write(fileBytes, , fileSize);
fileOut.close();
clientSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

请注意，这只是一个简单的示例，实际应用中可能需要更多的错误处理和安全性措施。