java实现ftp下载上传

Java可以通过FTPClient类来实现FTP的上传和下载。下面是一个简单的示例代码：

上传文件：

FTPClient ftpClient = new FTPClient();
try {
    ftpClient.connect(server, port);
    ftpClient.login(user, password);
    ftpClient.enterLocalPassiveMode();

    File file = new File(localFilePath);
    String remoteFilePath = "/remote/path/file.txt";
    InputStream inputStream = new FileInputStream(file);

    ftpClient.storeFile(remoteFilePath, inputStream);
    inputStream.close();
} catch (IOException ex) {
    ex.printStackTrace();
} finally {
    try {
        if (ftpClient.isConnected()) {
            ftpClient.logout();
            ftpClient.disconnect();
        }
    } catch (IOException ex) {
        ex.printStackTrace();
    }
}

下载文件：

FTPClient ftpClient = new FTPClient();
try {
    ftpClient.connect(server, port);
    ftpClient.login(user, password);
    ftpClient.enterLocalPassiveMode();

    String remoteFilePath = "/remote/path/file.txt";
    File downloadFile = new File(localFilePath);
    OutputStream outputStream = new BufferedOutputStream(new FileOutputStream(downloadFile));

    ftpClient.retrieveFile(remoteFilePath, outputStream);
    outputStream.close();
} catch (IOException ex) {
    ex.printStackTrace();
} finally {
    try {
        if (ftpClient.isConnected()) {
            ftpClient.logout();
            ftpClient.disconnect();
        }
    } catch (IOException ex) {
        ex.printStackTrace();
    }
}