在JAVA程序中，经常需要和FTP打交道，比如向FTP服务器上传文件、下载文件，本文简单介绍如何利用jakarta commons中的FTPClient（在commons-net包中）实现上传下载文件。
public static String ftpUpload(String url, String port, String
username,
String password, String remotePath, String fileNamePath,
String fileName) {
FTPClient ftpClient = new FTPClient();
FileInputStream fis = null;
String returnMessage = "0";
try {
ftpClient.connect(url, Integer.parseInt(port));
boolean loginResult = ftpClient.login(username,
password);
int returnCode = ftpClient.getReplyCode();
if (loginResult &&
FTPReply.isPositiveCompletion(returnCode)) {// 如果登录成功
ftpClient.makeDirectory(remotePath);
// 设置上传目录
ftpClient.changeWorkingDirectory(remotePath);
ftpClient.setBufferSize(1024);
ftpClient.setControlEncoding("UTF-8");
ftpClient.enterLocalPassiveMode();
fis = new FileInputStream(fileNamePath + fileName);
ftpClient.storeFile(fileName, fis);
returnMessage = "1"; // 上传成功
} else {// 如果登录失败
returnMessage = "0";
}
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException("FTP客户端出错！", e);
} finally {
// IOUtils.closeQuietly(fis);
try {
ftpClient.disconnect();
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException("关闭FTP连接发生异常！", e);
}
}
return returnMessage;
}