java开发文件传输

Java中可以使用Socket进行文件传输。下面是一个简单的示例代码：

服务端代码：

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

public class FileServer {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = null;
        try {
            serverSocket = new ServerSocket(8888); // 创建ServerSocket对象，监听端口8888
        } catch (IOException e) {
            System.err.println("Could not listen on port: 8888.");
            System.exit(1);
        }

        Socket clientSocket = null;
        try {
            System.out.println("Waiting for client...");
            clientSocket = serverSocket.accept(); // 等待客户端连接
            System.out.println("Client connected: " + clientSocket.getInetAddress().getHostName());
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

        // 接收文件
        InputStream in = clientSocket.getInputStream();
        OutputStream out = new FileOutputStream("received_file.txt");
        byte[] buffer = new byte[1024];
        int length;
        while ((length = in.read(buffer)) > 0) {
            out.write(buffer, 0, length);
        }
        in.close();
        out.close();

        clientSocket.close();
        serverSocket.close();
    }
}

客户端代码：

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

public class FileClient {
    public static void main(String[] args) throws IOException {
        String serverName = "localhost";
        int port = 8888;

        try {
            System.out.println("Connecting to " + serverName + " on port " + port);
            Socket clientSocket = new Socket(serverName, port); // 连接服务器
            System.out.println("Connected.");

            // 发送文件
            OutputStream out = clientSocket.getOutputStream();
            InputStream in = new FileInputStream("file_to_send.txt");
            byte[] buffer = new byte[1024];
            int length;
            while ((length = in.read(buffer)) > 0) {
                out.write(buffer, 0, length);
            }
            in.close();
            out.close();

            clientSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

这个示例代码中，服务端监听端口8888，客户端连接服务器后发送文件，服务端接收文件并保存为"received_file.txt"。你可以根据实际情况修改代码，比如修改文件名、路径、端口等。