Java FTP按关键字批量下载文件

╰半夏微凉° 2023-10-15 21:14 52阅读 0赞

## 一、所需jar ##

<dependency>
                <groupId>commons-net</groupId>
                <artifactId>commons-net</artifactId>
                <version>3.8.0</version>
            </dependency>

## 二、工具类 ##

import java.io.*;
    import java.net.URLConnection;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.apache.commons.net.ftp.FTP;
    import org.apache.commons.net.ftp.FTPClient;
    import org.apache.commons.net.ftp.FTPFile;
    public class FTPBulkFileDownloader {
    
        public static void downloadFiles(String server, int port, String user, String pass, String remoteDir, String saveDir, String keyword) throws IOException {
            FTPClient ftpClient = new FTPClient();
            try {
                ftpClient.connect(server, port);
                ftpClient.login(user, pass);
                ftpClient.enterLocalPassiveMode();
                ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
    
                List<String> filesToDownload = getFilesToDownload(ftpClient, remoteDir, keyword);
                for (String file : filesToDownload) {
                    String remoteFilePath = remoteDir + "/" + file;
                    String saveFilePath = saveDir + File.separator + file;
                    downloadFile(ftpClient, remoteFilePath, saveFilePath);
                }
            } finally {
                if (ftpClient.isConnected()) {
                    ftpClient.logout();
                    ftpClient.disconnect();
                }
            }
        }
    
        private static List<String> getFilesToDownload(FTPClient ftpClient, String remoteDir, String keyword) throws IOException {
            List<String> filesToDownload = new ArrayList<>();
            FTPFile[] files = ftpClient.listFiles(remoteDir);
            for (FTPFile file : files) {
                if (file.isFile() && file.getName().contains(keyword)) {
                    filesToDownload.add(file.getName());
                }
            }
            return filesToDownload;
        }
    
        private static void downloadFile(FTPClient ftpClient, String remoteFilePath, String saveFilePath) throws IOException {
            InputStream inputStream = ftpClient.retrieveFileStream(remoteFilePath);
            BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);
            FileOutputStream fileOutputStream = null;
            try {
                fileOutputStream = new FileOutputStream(saveFilePath);
                int bytesRead;
                byte[] buffer = new byte[1024];
                while ((bytesRead = bufferedInputStream.read(buffer)) != -1) {
                    fileOutputStream.write(buffer, 0, bytesRead);
                }
                System.out.println("File downloaded: " + saveFilePath);
            } finally {
                if (bufferedInputStream != null) {
                    bufferedInputStream.close();
                }
                if (fileOutputStream != null) {
                    fileOutputStream.close();
                }
                ftpClient.completePendingCommand();
            }
        }
        public static void main(String[] args) {
            String server = "FTPIP";
            //FTP端口
            int port = 21;
            //用户名
            String user = "";
            //密码
            String pass = "";
            //FTP文件目录
            String remoteDir = "/FTP";
            //本地文件存放目录
            String saveDir = "/local";
            //关键字
            String keyword = "222";
    
            try {
                downloadFiles(server, port, user, pass, remoteDir, saveDir, keyword);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }