linux FTP傳輸文件無響應

本地Windows開發環境下，FTP傳輸文件正常，但將服務部署到Linux環境時，會出現無響應的狀態。

1 在FTP服務中，涉及到客戶端和服務器端的連接，連接就會涉及到端口的打開問題；

2 而端口的打開中，又涉及到主動模式和被動模式。主動模式：客戶端開放端口給服務端用；被動模式：服務端開放端口給客戶端用。

由於很多客戶端在防火牆內，開放端口給服務器端用比較困難。所以用被動模式的時候比較多。

所以在storeFile(),listFiles()時之前需要調用  ftpClient.enterLocalPassiveMode();

這個方法的意思就是每次數據連接之前，ftpClient告訴ftp server開通一個端口來傳輸數據。

FTP傳輸文件

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;
import org.apache.commons.net.ftp.FTPReply;
import org.springframework.web.multipart.MultipartFile;

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

@Slf4j
public class FTPUtil {

    //ftp服務器地址
    private static String HOST_NAME = PropertiesUtil.getProperty("ftp.server.ip");

    //ftp服務器端口號默認爲21
    private static Integer PORT = Integer.valueOf(PropertiesUtil.getProperty("ftp.port"));

    //ftp登錄賬號
    private static String USERNAME = PropertiesUtil.getProperty("ftp.user");

    //ftp登錄密碼
    private static String PASSWORD = PropertiesUtil.getProperty("ftp.pass");

    private static FTPClient ftpClient = null;

    /**
     * 初始化ftp服務器
     */
    private static void initFtpClient() {
        ftpClient = new FTPClient();
        ftpClient.setControlEncoding("utf-8");
        try {
            log.info("connecting...ftp服務器:" + HOST_NAME + ":" + PORT);
            //連接ftp服務器
            ftpClient.connect(HOST_NAME, PORT);
            //登錄ftp服務器
            ftpClient.login(USERNAME, PASSWORD);

            ftpClient.sendCommand("OPTS UTF8", "ON");

            //是否成功登錄服務器
            int replyCode = ftpClient.getReplyCode();
            if (!FTPReply.isPositiveCompletion(replyCode)) {
                log.info("connect failed...ftp服務器:" + HOST_NAME + ":" + PORT);
            } else {
                log.info("connect successful...ftp服務器:" + HOST_NAME + ":" + PORT);
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 上傳文件
     *
     * @param pathname       ftp服務保存地址
     * @param fileName       上傳到ftp的文件名
     * @param originfilename 待上傳文件的名稱（絕對地址） *
     * @return
     */
    public static boolean uploadFile(String pathname, String fileName, String originfilename) {
        boolean flag = false;
        InputStream inputStream = null;
        try {
            log.info("開始上傳文件");
            inputStream = new FileInputStream(new File(originfilename));
            initFtpClient();
            ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
            CreateDirecroty(pathname);
            ftpClient.makeDirectory(pathname);
            ftpClient.changeWorkingDirectory(pathname);
            ftpClient.enterLocalPassiveMode();
            ftpClient.storeFile(fileName, inputStream);
            inputStream.close();
            ftpClient.logout();
            flag = true;
            log.info("上傳文件成功");
        } catch (Exception e) {
            log.info("上傳文件失敗");
            e.printStackTrace();
        } finally {
            if (ftpClient.isConnected()) {
                try {
                    ftpClient.disconnect();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (null != inputStream) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return true;
    }

    /**
     * 上傳文件
     * @param pathname ftp服務保存地址
     * @param file  文件
     * @param fileName  上傳到ftp的文件名
     * @return
     */
    public static boolean uploadFile(String pathname, MultipartFile file, String fileName) {
        boolean flag = false;
        try {
            initFtpClient();
            ftpClient.setFileType(FTPClient.BINARY_FILE_TYPE);
            CreateDirecroty(pathname);
            ftpClient.makeDirectory(pathname);
            ftpClient.changeWorkingDirectory(pathname);
            ftpClient.enterLocalPassiveMode();
            ftpClient.storeFile(fileName, file.getInputStream());
            ftpClient.logout();
            flag = true;
            log.info("上傳文件成功");
        } catch (Exception e) {
            log.info("上傳文件失敗");
            e.printStackTrace();
        } finally {
            if (ftpClient.isConnected()) {
                try {
                    ftpClient.disconnect();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return flag;
    }

    /**
     * 下載文件
     *
     * @param pathName
     * @param filename
     * @param out
     * @return
     */
    public static boolean downloadFile(String pathName, String filename, OutputStream out) {
        try {
            log.info("開始下載文件");
            initFtpClient();
            //切換FTP目錄
            ftpClient.changeWorkingDirectory(pathName);
            ftpClient.enterLocalPassiveMode();
            FTPFile[] ftpFiles = ftpClient.listFiles();
            for (FTPFile file : ftpFiles) {
                if (filename.equalsIgnoreCase(file.getName())) {
                    InputStream inputStream = ftpClient.retrieveFileStream(filename);
                    byte[] buffer = new byte[1024 * 4];
                    int n = 0;
                    while ((n = inputStream.read(buffer)) != -1) {
                        out.write(buffer, 0, n);
                    }
                    out.flush();
                }
            }
            ftpClient.logout();
            log.info("下載文件成功");
            return true;
        } catch (Exception e) {
            log.info("下載文件失敗");
            e.printStackTrace();
            return false;
        } finally {
            try {
                out.close();
                if (ftpClient.isConnected()) {
                    ftpClient.disconnect();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 刪除文件 *
     *
     * @param pathname FTP服務器保存目錄 *
     * @param filename 要刪除的文件名稱 *
     * @return
     */
    public static boolean deleteFile(String pathname, String filename) {
        boolean flag = false;
        try {
            log.info("開始刪除文件");
            initFtpClient();
            //切換FTP目錄
            ftpClient.changeWorkingDirectory(pathname);
            ftpClient.dele(filename);
            ftpClient.logout();
            flag = true;
            log.info("刪除文件成功");
        } catch (Exception e) {
            log.info("刪除文件失敗");
            e.printStackTrace();
        } finally {
            if (ftpClient.isConnected()) {
                try {
                    ftpClient.disconnect();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return flag;
    }

    /**
     * 改變目錄路徑
     */
    public static boolean changeWorkingDirectory(String directory) {
        boolean flag = true;
        try {
            flag = ftpClient.changeWorkingDirectory(directory);
            if (flag) {
                log.info("進入文件夾" + directory + " 成功！");

            } else {
                log.info("進入文件夾" + directory + " 失敗！開始創建文件夾");
            }
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
        return flag;
    }

    /**
     * 創建多層目錄文件，如果有ftp服務器已存在該文件，則不創建，如果無，則創建
     *
     * @param remote
     * @return
     * @throws IOException
     */
    public static boolean CreateDirecroty(String remote) throws IOException {
        boolean success = true;
        String directory = remote + "/";
        // 如果遠程目錄不存在，則遞歸創建遠程服務器目錄
        if (!directory.equalsIgnoreCase("/") && !changeWorkingDirectory(new String(directory))) {
            int start = 0;
            int end = 0;
            if (directory.startsWith("/")) {
                start = 1;
            } else {
                start = 0;
            }
            end = directory.indexOf("/", start);
            String path = "";
            String paths = "";
            while (true) {
                String subDirectory = remote.substring(start, end);
                path = path + "/" + subDirectory;
                if (!existFile(path)) {
                    if (makeDirectory(subDirectory)) {
                        changeWorkingDirectory(subDirectory);
                    } else {
                        log.info("創建目錄[" + subDirectory + "]失敗");
                        changeWorkingDirectory(subDirectory);
                    }
                } else {
                    changeWorkingDirectory(subDirectory);
                }

                paths = paths + "/" + subDirectory;
                start = end + 1;
                end = directory.indexOf("/", start);
                // 檢查所有目錄是否創建完畢
                if (end <= start) {
                    break;
                }
            }
        }
        return success;
    }

    /**
     * 判斷ftp服務器文件是否存在
     *
     * @param path
     * @return
     * @throws IOException
     */
    public static boolean existFile(String path) throws IOException {
        boolean flag = false;
        FTPFile[] ftpFileArr = ftpClient.listFiles(path);
        if (ftpFileArr.length > 0) {
            flag = true;
        }
        return flag;
    }

    /**
     * 創建目錄
     */
    public static boolean makeDirectory(String dir) {
        boolean flag = true;
        try {
            flag = ftpClient.makeDirectory(dir);
            if (flag) {
                log.info("創建文件夾" + dir + " 成功！");

            } else {
                log.info("創建文件夾" + dir + " 失敗！");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return flag;
    }

}

此外，保持連接的同時，需要對多個FTP文件進行操作，一定要調用completePendingCommand（）釋放，否則FTP會斷開連接

//操作多文件時候，必須調用completePendingCommand釋放,否則FTP會斷開連接
ftpClient.completePendingCommand();