安卓 ftp服务器 源码

以下是一个基于 Java 的 Android FTP 服务器的示例代码：

import android.os.Environment;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class FtpServer implements Runnable {

    private int port;
    private boolean running;
    private ServerSocket serverSocket;
    private String rootDir;

    public FtpServer(int port) {
        this.port = port;
        this.running = false;
        this.rootDir = Environment.getExternalStorageDirectory().getAbsolutePath();
    }

    @Override
    public void run() {
        try {
            serverSocket = new ServerSocket(port);
            running = true;
            System.out.println("FTP Server started on port " + port);

            while (running) {
                Socket clientSocket = serverSocket.accept();
                System.out.println("Client connected: " + clientSocket.getInetAddress().getHostAddress());

                FtpClientHandler clientHandler = new FtpClientHandler(clientSocket, rootDir);
                new Thread(clientHandler).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void stop() {
        running = false;
        try {
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private class FtpClientHandler implements Runnable {

        private Socket clientSocket;
        private String rootDir;

        public FtpClientHandler(Socket clientSocket, String rootDir) {
            this.clientSocket = clientSocket;
            this.rootDir = rootDir;
        }

        @Override
        public void run() {
            try {
                BufferedInputStream in = new BufferedInputStream(clientSocket.getInputStream());
                BufferedOutputStream out = new BufferedOutputStream(clientSocket.getOutputStream());

                out.write("220 Service ready for new user.\r\n".getBytes());
                out.flush();

                byte[] buffer = new byte[1024];
                int bytesRead;
                String command = "";
                while ((bytesRead = in.read(buffer)) != -1) {
                    String request = new String(buffer, 0, bytesRead);
                    System.out.print(request);

                    if (request.trim().equals("QUIT")) {
                        out.write("221 Goodbye.\r\n".getBytes());
                        out.flush();
                        break;
                    } else if (request.startsWith("USER ")) {
                        out.write("331 User name okay, need password.\r\n".getBytes());
                        out.flush();
                    } else if (request.startsWith("PASS ")) {
                        out.write("230 User logged in, proceed.\r\n".getBytes());
                        out.flush();
                    } else if (request.startsWith("PWD")) {
                        out.write(("257 \"" + rootDir + "\" is the current directory.\r\n").getBytes());
                        out.flush();
                    } else if (request.startsWith("CWD ")) {
                        String[] tokens = request.split(" ");
                        String dir = tokens[1];
                        File newDir = new File(rootDir + "/" + dir);
                        if (newDir.exists() && newDir.isDirectory()) {
                            rootDir = newDir.getAbsolutePath();
                            out.write(("250 Changed to directory \"" + rootDir + "\"\r\n").getBytes());
                            out.flush();
                        } else {
                            out.write("550 Failed to change directory.\r\n".getBytes());
                            out.flush();
                        }
                    } else if (request.startsWith("LIST")) {
                        File dir = new File(rootDir);
                        File[] files = dir.listFiles();
                        StringBuilder response = new StringBuilder();
                        for (File file : files) {
                            String name = file.getName();
                            String type = file.isDirectory() ? "d" : "-";
                            String size = String.valueOf(file.length());
                            response.append(type).append("rw-r--r-- 1 owner group ").append(size).append(" Jan 01 00:00 ").append(name).append("\r\n");
                        }
                        out.write(("150 Opening data connection for directory list\r\n").getBytes());
                        out.flush();
                        Socket dataSocket = new Socket(clientSocket.getInetAddress(), 20);
                        BufferedOutputStream dataOut = new BufferedOutputStream(dataSocket.getOutputStream());
                        dataOut.write(response.toString().getBytes());
                        dataOut.flush();
                        dataOut.close();
                        dataSocket.close();
                        out.write("226 Directory send OK.\r\n".getBytes());
                        out.flush();
                    } else if (request.startsWith("RETR ")) {
                        String[] tokens = request.split(" ");
                        String fileName = tokens[1];
                        File file = new File(rootDir + "/" + fileName);
                        if (file.exists() && file.isFile()) {
                            out.write(("150 Opening data connection for " + fileName + "\r\n").getBytes());
                            out.flush();
                            Socket dataSocket = new Socket(clientSocket.getInetAddress(), 20);
                            BufferedOutputStream dataOut = new BufferedOutputStream(dataSocket.getOutputStream());
                            BufferedInputStream fileIn = new BufferedInputStream(new FileInputStream(file));
                            byte[] fileBuffer = new byte[1024];
                            int fileBytesRead;
                            while ((fileBytesRead = fileIn.read(fileBuffer)) != -1) {
                                dataOut.write(fileBuffer, 0, fileBytesRead);
                                dataOut.flush();
                            }
                            fileIn.close();
                            dataOut.close();
                            dataSocket.close();
                            out.write("226 Transfer complete.\r\n".getBytes());
                            out.flush();
                        } else {
                            out.write(("550 Failed to open file " + fileName + "\r\n").getBytes());
                            out.flush();
                        }
                    } else {
                        out.write("502 Command not implemented.\r\n".getBytes());
                        out.flush();
                    }

                    buffer = new byte[1024];
                }

                clientSocket.close();
                System.out.println("Client disconnected.");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

此代码实现了一个简单的 FTP 服务器，支持用户登录、切换目录、列出文件列表、下载文件等基本功能。请注意，此代码仅供参考，实际使用时需要进行适当修改和优化。